aboutsummaryrefslogtreecommitdiff
path: root/tools/tracing
AgeCommit message (Collapse)AuthorFilesLines
2024-05-23tools/latency-collector: Fix -Wformat-security compile warnsGravatar Shuah Khan 1-4/+4
Fix the following -Wformat-security compile warnings adding missing format arguments: latency-collector.c: In function ‘show_available’: latency-collector.c:938:17: warning: format not a string literal and no format arguments [-Wformat-security] 938 | warnx(no_tracer_msg); | ^~~~~ latency-collector.c:943:17: warning: format not a string literal and no format arguments [-Wformat-security] 943 | warnx(no_latency_tr_msg); | ^~~~~ latency-collector.c: In function ‘find_default_tracer’: latency-collector.c:986:25: warning: format not a string literal and no format arguments [-Wformat-security] 986 | errx(EXIT_FAILURE, no_tracer_msg); | ^~~~ latency-collector.c: In function ‘scan_arguments’: latency-collector.c:1881:33: warning: format not a string literal and no format arguments [-Wformat-security] 1881 | errx(EXIT_FAILURE, no_tracer_msg); | ^~~~ Link: https://lore.kernel.org/linux-trace-kernel/20240404011009.32945-1-skhan@linuxfoundation.org Cc: stable@vger.kernel.org Fixes: e23db805da2df ("tracing/tools: Add the latency-collector to tools directory") Signed-off-by: Shuah Khan <skhan@linuxfoundation.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-05-16rtla: Fix -t\--trace[=file]Gravatar John Kacur 4-20/+36
The -t option has an optional argument. The usual case is for a short option to be specified without an '=' and for the long version to be specified with an '=' Various forms of this do not work as expected. For example: rtla timerlat hist -T50 -tfile.txt will result in a truncated file name of "ile.txt" Another example is that the long form without the '=' will result in the default file name instead of the requested file name. This patch properly parses the optional argument with and without '=' and with and without spaces for the short form. This patch was also tested using -t and --trace without providing a file name both as the last requested option and with a following long and short option. For example: rtla timerlat hist -T50 -t -u rtla timerlat hist -T50 --trace -u This fix is applied to both timerlat top and hist and to osnoise top and hist. Here is the full testing for rtla timerlat hist. Before applying the patch rtla timerlat hist -T50 -t=file.txt Works as expected, "file.txt" rtla timerlat hist -T50 -tfile.txt Truncated file name "ile.txt" rtla timerlat hist -T50 -t file.txt Default file name instead of file.txt rtla timerlat hist -T50 --trace=file.txt Truncated file name "ile.txt" rtla timerlat hist -T50 --trace file.txt Default file name "timerlat_trace.txt" instead of "file.txt" After applying the patch: rtla timerlat hist -T50 -t=file.txt Works as expected, "file.txt" rtla timerlat hist -T50 -tfile.txt Works as expected, "file.txt" rtla timerlat hist -T50 -t file.txt Works as expected, "file.txt" rtla timerlat hist -T50 --trace=file.txt Works as expected, "file.txt" rtla timerlat hist -T50 --trace file.txt Works as expected, "file.txt" In addition the following tests were performed to make sure that the default file name worked as expected including with trailing options. rtla timerlat hist -T50 -t Works as expected "timerlat_trace.txt" rtla timerlat hist -T50 --trace Works as expected "timerlat_trace.txt" rtla timerlat hist -T50 -t -u Works as expected "timerlat_trace.txt" rtla timerlat hist -T50 --trace -u Works as expected "timerlat_trace.txt" Link: https://lkml.kernel.org/r/20240515183024.59985-1-jkacur@redhat.com Cc: Daniel Bristot de Oliveria <bristot@kernel.org> Signed-off-by: John Kacur <jkacur@redhat.com> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
2024-05-16rtla/timerlat: Fix histogram report when a cpu count is 0Gravatar John Kacur 1-18/+42
On short runs it is possible to get no samples on a cpu, like this: # rtla timerlat hist -u -T50 Index IRQ-001 Thr-001 Usr-001 IRQ-002 Thr-002 Usr-002 2 1 0 0 0 0 0 33 0 1 0 0 0 0 36 0 0 1 0 0 0 49 0 0 0 1 0 0 52 0 0 0 0 1 0 over: 0 0 0 0 0 0 count: 1 1 1 1 1 0 min: 2 33 36 49 52 18446744073709551615 avg: 2 33 36 49 52 - max: 2 33 36 49 52 0 rtla timerlat hit stop tracing IRQ handler delay: (exit from idle) 48.21 us (91.09 %) IRQ latency: 49.11 us Timerlat IRQ duration: 2.17 us (4.09 %) Blocking thread: 1.01 us (1.90 %) swapper/2:0 1.01 us ------------------------------------------------------------------------ Thread latency: 52.93 us (100%) Max timerlat IRQ latency from idle: 49.11 us in cpu 2 Note, the value 18446744073709551615 is the same as ~0. Fix this by reporting no results for the min, avg and max if the count is 0. Link: https://lkml.kernel.org/r/20240510190318.44295-1-jkacur@redhat.com Cc: stable@vger.kernel.org Fixes: 1eeb6328e8b3 ("rtla/timerlat: Add timerlat hist mode") Suggested-by: Daniel Bristot de Oliveria <bristot@kernel.org> Signed-off-by: John Kacur <jkacur@redhat.com> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
2024-05-16rtla: Add --trace-buffer-size optionGravatar Daniel Bristot de Oliveira 7-5/+68
Add the option allow the users to set a different buffer size for the trace. For example, in large systems, the user might be interested on reducing the trace buffer to avoid large tracing files. The buffer size is specified in kB, and it is only affecting the tracing instance. The function trace_set_buffer_size() appears on libtracefs v1.6, so increase the minimum required version on Makefile.config. Link: https://lkml.kernel.org/r/e7c9ca5b3865f28e131a49ec3b984fadf2d056c6.1715860611.git.bristot@kernel.org Cc: Jonathan Corbet <corbet@lwn.net> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: John Kacur <jkacur@redhat.com> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
2024-05-15rtla/timerlat: Make user-space threads the defaultGravatar Daniel Bristot de Oliveira 2-6/+56
After ther -u addition, most of the known users are setting it. And it makes sense, as it adds more information, and inherits the default setup for the threads - e.g., cgroups configs. Thus, if the user-space interface is available, enable -u. Otherwise, use the in-kernel thread. Add the -k option to allow the user to request kernel-threads. Link: https://lkml.kernel.org/r/9241d3089de4091b124f780ed832a0e6646cadaa.1713968967.git.bristot@kernel.org Cc: Jonathan Corbet <corbet@lwn.net> Cc: Juri Lelli <juri.lelli@redhat.com> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
2024-05-15rtla: Add the --warm-up optionGravatar Daniel Bristot de Oliveira 4-40/+115
On many cases, the results right after the startup are different from the rest of the execution, biasing the results. For example, on osnoise, the scheduler might take some time to adapt to the new busy-loop workload. Add the --warm-up <seconds> option, adding a warm-up phase (in seconds) where the workload is set, but the results are discarded. Link: https://lkml.kernel.org/r/e682d5ce5af90f123bd13220f63d5c3d118a92be.1713968967.git.bristot@kernel.org Cc: Jonathan Corbet <corbet@lwn.net> Cc: Juri Lelli <juri.lelli@redhat.com> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
2024-05-15rtla/timerlat: Add a summary for hist modeGravatar Daniel Bristot de Oliveira 1-1/+129
Like on rtla timerlat top, add an overall summary at the bottom of timerlat hist. For instance: # timerlat hist -c 0-1 -d 10s -E 20 # RTLA timerlat histogram # Time unit is microseconds (us) # Duration: 0 00:00:10 Index IRQ-000 Thr-000 IRQ-001 Thr-001 6 1 0 0 0 7 1 0 0 0 8 1 0 1 0 9 7 0 0 0 10 16 0 0 0 11 1 0 3 0 15 0 0 3 0 16 0 0 12 0 17 0 0 28 0 18 0 2 26 0 19 1 1 80 1 over: 9973 9998 9848 10000 count: 10001 10001 10001 10001 min: 6 18 8 19 avg: 185 204 95 113 max: 428 450 341 371 ALL: IRQ Thr count: 20002 20002 min: 6 18 avg: 140 159 max: 428 450 Link: https://lkml.kernel.org/r/a6bc06c798f72127edc57d1f99da8d57e1187cee.1713968967.git.bristot@kernel.org Cc: Jonathan Corbet <corbet@lwn.net> Suggested-by: Juri Lelli <juri.lelli@redhat.com> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
2024-05-15rtla/timerlat: Add a summary for top modeGravatar Daniel Bristot de Oliveira 1-0/+108
While the per-cpu values are the results to take into consideration, the overall system values are also useful. Add a summary at the bottom of rtla timerlat top showing the overall results. For instance: Timer Latency 0 00:00:10 | IRQ Timer Latency (us) | Thread Timer Latency (us) CPU COUNT | cur min avg max | cur min avg max 0 #10003 | 113 19 150 441 | 134 35 170 459 1 #10003 | 63 8 99 462 | 84 15 119 481 2 #10003 | 3 2 89 396 | 21 8 108 414 3 #10002 | 206 11 210 394 | 223 21 228 415 ---------------|----------------------------------------|--------------------------------------- ALL #40011 e0 | 2 137 462 | 8 156 481 Link: https://lkml.kernel.org/r/5eb510d6faeb4ce745e09395196752df75a2dd1a.1713968967.git.bristot@kernel.org Cc: Jonathan Corbet <corbet@lwn.net> Suggested-by: Juri Lelli <juri.lelli@redhat.com> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
2024-05-15rtla/timerlat: Use pretty formatting only on interactive ttyGravatar Daniel Bristot de Oliveira 1-7/+18
timerlat top does some background/font color formatting. While useful on terminal, it breaks the output on other formats. For example, when piping the output for pastebin tools, the format strings are printed as characters. For instance: [2;37;40m Timer Latency [0;0;0m 0 00:00:01 | IRQ Timer Latency (us) | Thread Timer Latency (us) [2;30;47mCPU COUNT | cur min avg max | cur min avg max[0;0;0m 0 #1013 | 1 0 1 54 | 5 2 4 57 1 #1013 | 3 0 1 10 | 6 2 4 15 To avoid this problem, do the formatting only if running on a tty, and in !quiet mode. Link: https://lkml.kernel.org/r/8288e1544ceab21557d5dda93a0f00339497c649.1713968967.git.bristot@kernel.org Cc: Jonathan Corbet <corbet@lwn.net> Cc: Juri Lelli <juri.lelli@redhat.com> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
2024-05-15rtla/auto-analysis: Replace \t with spacesGravatar Daniel Bristot de Oliveira 1-46/+63
When copying timerlat auto-analysis from a terminal to some web pages or chats, the \t are being replaced with a single ' ' or ' ', breaking the output. For example: ## CPU 3 hit stop tracing, analyzing it ## IRQ handler delay: 1.30 us (0.11 %) IRQ latency: 1.90 us Timerlat IRQ duration: 3.00 us (0.24 %) Blocking thread: 1223.16 us (99.00 %) insync:4048 1223.16 us IRQ interference 4.93 us (0.40 %) local_timer:236 4.93 us ------------------------------------------------------------------------ Thread latency: 1235.47 us (100%) Replace \t with spaces to avoid this problem. Link: https://lkml.kernel.org/r/ec7ed2b2809c22ab0dfc8eb7c805ab9cddc4254a.1713968967.git.bristot@kernel.org Cc: stable@vger.kernel.org Cc: Jonathan Corbet <corbet@lwn.net> Cc: Juri Lelli <juri.lelli@redhat.com> Fixes: 27e348b221f6 ("rtla/timerlat: Add auto-analysis core") Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
2024-05-15rtla/timerlat: Simplify "no value" printing on topGravatar Daniel Bristot de Oliveira 1-12/+5
Instead of printing three times the same output, print it only once, reducing lines and being sure that all no values have the same length. It also fixes an extra '\n' when running the with kernel threads, like here: =============== %< ============== Timer Latency 0 00:00:01 | IRQ Timer Latency (us) | Thread Timer Latency (us) CPU COUNT | cur min avg max | cur min avg max 2 #0 | - - - - | 161 161 161 161 3 #0 | - - - - | 161 161 161 161 8 #1 | 54 54 54 54 | - - - -'\n' ---------------|----------------------------------------|--------------------------------------- ALL #1 e0 | 54 54 54 | 161 161 161 =============== %< ============== This '\n' should have been removed with the user-space support that added another '\n' if not running with kernel threads. Link: https://lkml.kernel.org/r/0a4d8085e7cd706733a5dc10a81ca38b82bd4992.1713968967.git.bristot@kernel.org Cc: stable@vger.kernel.org Cc: Jonathan Corbet <corbet@lwn.net> Cc: Juri Lelli <juri.lelli@redhat.com> Fixes: cdca4f4e5e8e ("rtla/timerlat_top: Add timerlat user-space support") Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
2024-03-20tools/rtla: Add -U/--user-load option to timerlatGravatar Daniel Bristot de Oliveira 3-9/+95
The timerlat tracer provides an interface for any application to wait for the timerlat's periodic wakeup. Currently, rtla timerlat uses it to dispatch its user-space workload (-u option). But as the tracer interface is generic, rtla timerlat can also be used to monitor any workload that uses it. For example, a user might place their own workload to wait on the tracer interface, and monitor the results with rtla timerlat. Add the -U option to rtla timerlat top and hist. With this option, rtla timerlat will not dispatch its workload but only setting up the system, waiting for a user to dispatch its workload. The sample code in this patch is an example of python application that loops in the timerlat tracer fd. To use it, dispatch: # rtla timerlat -U In a terminal, then run the python program on another terminal, specifying the CPU to run it. For example, setting on CPU 1: #./timerlat_load.py 1 Then rtla timerlat will start printing the statistics of the ./timerlat_load.py app. An interesting point is that the "Ret user Timer Latency" value is the overall response time of the load. The sample load does a memory copy to exemplify that. The stop tracing options on rtla timerlat works in this setup as well, including auto analysis. Link: https://lkml.kernel.org/r/36e6bcf18fe15c7601048fd4c65aeb193c502cc8.1707229706.git.bristot@kernel.org Cc: Jonathan Corbet <corbet@lwn.net> Cc: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
2024-03-20tools/rtla: Use tools/build makefiles to build rtlaGravatar Daniel Bristot de Oliveira 7-145/+244
Use tools/build/ makefiles to build rtla, inheriting the benefits of it. For example, having a proper way to handle dependencies. rtla is built using perf infra-structure when building inside the kernel tree. At this point, rtla diverges from perf in two points: Documentation and tarball generation/build. At the documentation level, rtla is one step ahead, placing the documentation at Documentation/tools/rtla/, using the same build tools as kernel documentation. The idea is to move perf documentation to the same scheme and then share the same makefiles. rtla has a tarball target that the (old) RHEL8 uses. The tarball was kept using a simple standalone makefile for compatibility. The standalone makefile shares most of the code, e.g., flags, with regular buildings. The tarball method was set as deprecated. If necessary, we can make a rtla tarball like perf, which includes the entire tools/build. But this would also require changes in the user side (the directory structure changes, and probably the deps to build the package). Inspired on perf and objtool. Link: https://lkml.kernel.org/r/57563abf2715d22515c0c54a87cff3849eca5d52.1710519524.git.bristot@kernel.org Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Josh Poimboeuf <jpoimboe@kernel.org> Cc: John Kacur <jkacur@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Jiri Olsa <jolsa@kernel.org> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
2024-03-20tools/tracing: Use tools/build makefiles on latency-collectorGravatar Daniel Bristot de Oliveira 4-19/+122
Use tools/build/ makefiles to build latency-collector, inheriting the benefits of it. For example: Before this patch, a missing tracefs/traceevents headers will result in fail like this: ~/linux/tools/tracing/latency $ make cc -Wall -Wextra -g -O2 -o latency-collector latency-collector.c -lpthread latency-collector.c:26:10: fatal error: tracefs.h: No such file or directory 26 | #include <tracefs.h> | ^~~~~~~~~~~ compilation terminated. make: *** [Makefile:14: latency-collector] Error 1 Which is not that helpful. After this change it reports: ~/linux/tools/tracing/latency# make Auto-detecting system features: ... libtraceevent: [ OFF ] ... libtracefs: [ OFF ] libtraceevent is missing. Please install libtraceevent-dev/libtraceevent-devel libtracefs is missing. Please install libtracefs-dev/libtracefs-devel Makefile.config:29: *** Please, check the errors above.. Stop. This type of output is common across other tools in tools/ like perf and objtool. Link: https://lkml.kernel.org/r/872420b0880b11304e4ba144a0086c6478c5b469.1710519524.git.bristot@kernel.org Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Josh Poimboeuf <jpoimboe@kernel.org> Cc: John Kacur <jkacur@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Jiri Olsa <jolsa@kernel.org> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
2024-02-12tools/rtla: Exit with EXIT_SUCCESS when help is invokedGravatar John Kacur 4-4/+20
Fix rtla so that the following commands exit with 0 when help is invoked rtla osnoise top -h rtla osnoise hist -h rtla timerlat top -h rtla timerlat hist -h Link: https://lore.kernel.org/linux-trace-devel/20240203001607.69703-1-jkacur@redhat.com Cc: stable@vger.kernel.org Fixes: 1eeb6328e8b3 ("rtla/timerlat: Add timerlat hist mode") Signed-off-by: John Kacur <jkacur@redhat.com> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
2024-02-12tools/rtla: Replace setting prio with nice for SCHED_OTHERGravatar limingming3 2-3/+5
Since the sched_priority for SCHED_OTHER is always 0, it makes no sence to set it. Setting nice for SCHED_OTHER seems more meaningful. Link: https://lkml.kernel.org/r/20240207065142.1753909-1-limingming3@lixiang.com Cc: stable@vger.kernel.org Fixes: b1696371d865 ("rtla: Helper functions for rtla") Signed-off-by: limingming3 <limingming3@lixiang.com> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
2024-02-12tools/rtla: Remove unused sched_getattr() functionGravatar Daniel Bristot de Oliveira 1-6/+0
Clang is reporting: $ make HOSTCC=clang CC=clang LLVM_IAS=1 [...] clang -O -g -DVERSION=\"6.8.0-rc3\" -flto=auto -fexceptions -fstack-protector-strong -fasynchronous-unwind-tables -fstack-clash-protection -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS $(pkg-config --cflags libtracefs) -c -o src/utils.o src/utils.c src/utils.c:241:19: warning: unused function 'sched_getattr' [-Wunused-function] 241 | static inline int sched_getattr(pid_t pid, struct sched_attr *attr, | ^~~~~~~~~~~~~ 1 warning generated. Which is correct, so remove the unused function. Link: https://lkml.kernel.org/r/eaed7ba122c4ae88ce71277c824ef41cbf789385.1707217097.git.bristot@kernel.org Cc: stable@vger.kernel.org Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Nathan Chancellor <nathan@kernel.org> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: Bill Wendling <morbo@google.com> Cc: Justin Stitt <justinstitt@google.com> Cc: Donald Zickus <dzickus@redhat.com> Fixes: b1696371d865 ("rtla: Helper functions for rtla") Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
2024-02-12tools/rtla: Fix clang warning about mount_point var sizeGravatar Daniel Bristot de Oliveira 1-1/+1
clang is reporting this warning: $ make HOSTCC=clang CC=clang LLVM_IAS=1 [...] clang -O -g -DVERSION=\"6.8.0-rc3\" -flto=auto -fexceptions -fstack-protector-strong -fasynchronous-unwind-tables -fstack-clash-protection -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS $(pkg-config --cflags libtracefs) -c -o src/utils.o src/utils.c src/utils.c:548:66: warning: 'fscanf' may overflow; destination buffer in argument 3 has size 1024, but the corresponding specifier may require size 1025 [-Wfortify-source] 548 | while (fscanf(fp, "%*s %" STR(MAX_PATH) "s %99s %*s %*d %*d\n", mount_point, type) == 2) { | ^ Increase mount_point variable size to MAX_PATH+1 to avoid the overflow. Link: https://lkml.kernel.org/r/1b46712e93a2f4153909514a36016959dcc4021c.1707217097.git.bristot@kernel.org Cc: stable@vger.kernel.org Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Nathan Chancellor <nathan@kernel.org> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: Bill Wendling <morbo@google.com> Cc: Justin Stitt <justinstitt@google.com> Cc: Donald Zickus <dzickus@redhat.com> Fixes: a957cbc02531 ("rtla: Add -C cgroup support") Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
2024-02-12tools/rtla: Fix uninitialized bucket/data->bucket_size warningGravatar Daniel Bristot de Oliveira 2-4/+2
When compiling rtla with clang, I am getting the following warnings: $ make HOSTCC=clang CC=clang LLVM_IAS=1 [..] clang -O -g -DVERSION=\"6.8.0-rc3\" -flto=auto -fexceptions -fstack-protector-strong -fasynchronous-unwind-tables -fstack-clash-protection -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS $(pkg-config --cflags libtracefs) -c -o src/osnoise_hist.o src/osnoise_hist.c src/osnoise_hist.c:138:6: warning: variable 'bucket' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized] 138 | if (data->bucket_size) | ^~~~~~~~~~~~~~~~~ src/osnoise_hist.c:149:6: note: uninitialized use occurs here 149 | if (bucket < entries) | ^~~~~~ src/osnoise_hist.c:138:2: note: remove the 'if' if its condition is always true 138 | if (data->bucket_size) | ^~~~~~~~~~~~~~~~~~~~~~ 139 | bucket = duration / data->bucket_size; src/osnoise_hist.c:132:12: note: initialize the variable 'bucket' to silence this warning 132 | int bucket; | ^ | = 0 1 warning generated. [...] clang -O -g -DVERSION=\"6.8.0-rc3\" -flto=auto -fexceptions -fstack-protector-strong -fasynchronous-unwind-tables -fstack-clash-protection -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS $(pkg-config --cflags libtracefs) -c -o src/timerlat_hist.o src/timerlat_hist.c src/timerlat_hist.c:181:6: warning: variable 'bucket' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized] 181 | if (data->bucket_size) | ^~~~~~~~~~~~~~~~~ src/timerlat_hist.c:204:6: note: uninitialized use occurs here 204 | if (bucket < entries) | ^~~~~~ src/timerlat_hist.c:181:2: note: remove the 'if' if its condition is always true 181 | if (data->bucket_size) | ^~~~~~~~~~~~~~~~~~~~~~ 182 | bucket = latency / data->bucket_size; src/timerlat_hist.c:175:12: note: initialize the variable 'bucket' to silence this warning 175 | int bucket; | ^ | = 0 1 warning generated. This is a legit warning, but data->bucket_size is always > 0 (see timerlat_hist_parse_args()), so the if is not necessary. Remove the unneeded if (data->bucket_size) to avoid the warning. Link: https://lkml.kernel.org/r/6e1b1665cd99042ae705b3e0fc410858c4c42346.1707217097.git.bristot@kernel.org Cc: stable@vger.kernel.org Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Nathan Chancellor <nathan@kernel.org> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: Bill Wendling <morbo@google.com> Cc: Justin Stitt <justinstitt@google.com> Cc: Donald Zickus <dzickus@redhat.com> Fixes: 1eeb6328e8b3 ("rtla/timerlat: Add timerlat hist mode") Fixes: 829a6c0b5698 ("rtla/osnoise: Add the hist mode") Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
2024-02-12tools/rtla: Fix Makefile compiler options for clangGravatar Daniel Bristot de Oliveira 1-1/+6
The following errors are showing up when compiling rtla with clang: $ make HOSTCC=clang CC=clang LLVM_IAS=1 [...] clang -O -g -DVERSION=\"6.8.0-rc1\" -flto=auto -ffat-lto-objects -fexceptions -fstack-protector-strong -fasynchronous-unwind-tables -fstack-clash-protection -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -Wno-maybe-uninitialized $(pkg-config --cflags libtracefs) -c -o src/utils.o src/utils.c clang: warning: optimization flag '-ffat-lto-objects' is not supported [-Wignored-optimization-argument] warning: unknown warning option '-Wno-maybe-uninitialized'; did you mean '-Wno-uninitialized'? [-Wunknown-warning-option] 1 warning generated. clang -o rtla -ggdb src/osnoise.o src/osnoise_hist.o src/osnoise_top.o src/rtla.o src/timerlat_aa.o src/timerlat.o src/timerlat_hist.o src/timerlat_top.o src/timerlat_u.o src/trace.o src/utils.o $(pkg-config --libs libtracefs) src/osnoise.o: file not recognized: file format not recognized clang: error: linker command failed with exit code 1 (use -v to see invocation) make: *** [Makefile:110: rtla] Error 1 Solve these issues by: - removing -ffat-lto-objects and -Wno-maybe-uninitialized if using clang - informing the linker about -flto=auto Link: https://lore.kernel.org/linux-trace-kernel/567ac1b94effc228ce9a0225b9df7232a9b35b55.1707217097.git.bristot@kernel.org Cc: stable@vger.kernel.org Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Nathan Chancellor <nathan@kernel.org> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: Bill Wendling <morbo@google.com> Cc: Justin Stitt <justinstitt@google.com> Fixes: 1a7b22ab15eb ("tools/rtla: Build with EXTRA_{C,LD}FLAGS") Suggested-by: Donald Zickus <dzickus@redhat.com> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
2023-10-30rtla: Fix uninitialized variable foundGravatar Colin Ian King 1-1/+1
Variable found is not being initialized, in the case where the desired mount is not found the variable contains garbage. Fix this by initializing it to zero. Link: https://lore.kernel.org/all/20230727150117.627730-1-colin.i.king@gmail.com/ Fixes: a957cbc02531 ("rtla: Add -C cgroup support") Signed-off-by: Colin Ian King <colin.i.king@gmail.com> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
2023-09-22rtla/timerlat: Do not stop user-space if a cpu is offlineGravatar Daniel Bristot de Oliveira 1-2/+4
If no CPU list is passed, timerlat in user-space will dispatch one thread per sysconf(_SC_NPROCESSORS_CONF). However, not all CPU might be available, for instance, if HT is disabled. Currently, rtla timerlat is stopping the session if an user-space thread cannot set affinity to a CPU, or if a running user-space thread is killed. However, this is too restrictive. So, reduce the error to a debug message, and rtla timerlat run as long as there is at least one user-space thread alive. Link: https://lore.kernel.org/lkml/59cf2c882900ab7de91c6ee33b382ac7fa6b4ed0.1694781909.git.bristot@kernel.org Fixes: cdca4f4e5e8e ("rtla/timerlat_top: Add timerlat user-space support") Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
2023-09-12rtla/timerlat_aa: Fix previous IRQ delay for IRQs that happens after thread ↵Gravatar Daniel Bristot de Oliveira 1-5/+8
sample timerlat auto-analysis takes note of all IRQs, before or after the execution of the timerlat thread. Because we cannot go backward in the trace (we will fix it when moving to trace-cmd lib?), timerlat aa take note of the last IRQ execution in the waiting for the IRQ state, and then print it if it is executed after the expected timer IRQ starting time. After the thread sample, the timerlat starts recording the next IRQs as "previous" irq for the next occurrence. However, if an IRQ happens after the thread measurement but before the tracing stops, it is classified as a previous IRQ. That is not wrong, as it can be "previous" for the subsequent activation. What is wrong is considering it as a potential source for the last activation. Ignore the IRQ interference that happens after the IRQ starting time for now. A future improvement for timerlat can be either keeping a list of previous IRQ execution or using the trace-cmd library. Still, it requires further investigation - it is a new feature. Link: https://lore.kernel.org/lkml/a44a3f5c801dcc697bacf7325b65d4a5b0460537.1691162043.git.bristot@kernel.org Fixes: 27e348b221f6 ("rtla/timerlat: Add auto-analysis core") Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
2023-09-12rtla/timerlat_aa: Fix negative IRQ delayGravatar Daniel Bristot de Oliveira 1-1/+17
When estimating the IRQ timer delay, we are dealing with two different clock sources: the external clock source that timerlat uses as a reference and the clock used by the tracer. There are also two moments: the time reading the clock and the timer in which the event is placed in the buffer (the trace event timestamp). If the processor is slow or there is some hardware noise, the difference between the timestamp and the external clock, read can be longer than the IRQ handler delay, resulting in a negative time. If so, set IRQ to start delay as 0. In the end, it is less near-zero and relevant then the noise. Link: https://lore.kernel.org/lkml/a066fb667c7136d86dcddb3c7ccd72587db3e7c7.1691162043.git.bristot@kernel.org Fixes: 27e348b221f6 ("rtla/timerlat: Add auto-analysis core") Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
2023-09-12rtla/timerlat_aa: Zero thread sum after every sample analysisGravatar Daniel Bristot de Oliveira 1-0/+1
The thread thread_thread_sum accounts for thread interference during a single activation. It was not being zeroed, so it was accumulating thread interference over all activations. It was not that visible when timerlat was the highest priority. Link: https://lore.kernel.org/lkml/97bff55b0141f2d01b47d9450a5672fde147b89a.1691162043.git.bristot@kernel.org Fixes: 27e348b221f6 ("rtla/timerlat: Add auto-analysis core") Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
2023-06-13rtla/timerlat_hist: Add timerlat user-space supportGravatar Daniel Bristot de Oliveira 1-11/+118
Add the support for running timerlat threads in user-space. In this mode, enabled with -u/--user-threads, timerlat dispatches user-space processes that will loop in the timerlat_fd, measuring the overhead for going to user-space and then returning to the kernel - in addition to the existing measurements. Here is one example of the tool's output with -u enabled: $ sudo timerlat hist -u -c 1-3 -d 600 # RTLA timerlat histogram # Time unit is microseconds (us) # Duration: 0 00:10:01 Index IRQ-001 Thr-001 Usr-001 IRQ-002 Thr-002 Usr-002 IRQ-003 Thr-003 Usr-003 0 477555 0 0 425287 0 0 474357 0 0 1 122385 7998 0 174616 1921 0 125412 3138 0 2 47 587376 492150 89 594717 447830 147 593463 454872 3 11 2549 101930 7 2682 145580 64 2530 138680 4 3 1954 2833 1 463 4917 11 548 4656 5 0 60 1037 0 138 1117 6 179 1130 6 0 26 1837 0 38 277 1 76 339 7 0 15 143 0 28 147 2 37 156 8 0 10 23 0 11 75 0 12 80 9 0 7 17 0 0 26 0 11 42 10 0 2 11 0 0 18 0 2 20 11 0 0 7 0 1 8 0 2 12 12 0 0 6 0 1 4 0 2 8 13 0 1 3 0 0 0 0 0 1 14 0 1 0 0 0 1 0 0 2 15 0 1 0 0 0 0 0 0 2 16 0 1 2 0 0 0 0 0 0 17 0 0 1 0 0 0 0 0 0 19 0 0 1 0 0 0 0 0 0 over: 0 0 0 0 0 0 0 0 0 count: 600001 600001 600001 600000 600000 600000 600000 600000 600000 min: 0 1 2 0 1 2 0 1 2 avg: 0 1 2 0 2 2 0 2 2 max: 4 16 19 4 12 14 7 12 15 The tuning setup like -p or -C work for the user-space threads as well. Link: https://lkml.kernel.org/r/b6a042d55003c4a67ff7dce28d96044b7044f00d.1686066600.git.bristot@kernel.org Cc: William White <chwhite@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Tested-by: Juri Lelli <juri.lelli@redhat.com> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-06-13rtla/timerlat_top: Add timerlat user-space supportGravatar Daniel Bristot de Oliveira 7-6/+474
Add the support for running timerlat threads in user-space. In this mode, enabled with -u/--user-threads, timerlat dispatches user-space processes that will loop in the timerlat_fd, measuring the overhead for going to user-space and then returning to the kernel - in addition to the existing measurements. Here is one example of the tool's output with -u enabled: $ sudo timerlat top -u -d 600 -q Timer Latency 0 00:10:01 | IRQ Timer Latency (us) | Thread Timer Latency (us) | Ret user Timer Latency (us) CPU COUNT | cur min avg max | cur min avg max | cur min avg max 0 #600001 | 0 0 0 3 | 2 1 2 9 | 3 2 3 15 1 #600001 | 0 0 0 2 | 2 1 2 13 | 2 2 3 18 2 #600001 | 0 0 0 10 | 2 1 2 16 | 3 2 3 20 3 #600001 | 0 0 0 7 | 2 1 2 10 | 3 2 3 11 4 #600000 | 0 0 0 16 | 2 1 2 41 | 3 2 3 58 5 #600000 | 0 0 0 3 | 2 1 2 10 | 3 2 3 13 6 #600000 | 0 0 0 5 | 2 1 2 7 | 3 2 3 10 7 #600000 | 0 0 0 1 | 2 1 2 7 | 3 2 3 10 The tuning setup like -p or -C work for the user-space threads as well. Link: https://lkml.kernel.org/r/758ad2292a0a1d884138d08219e1a0f572d257a2.1686066600.git.bristot@kernel.org Cc: William White <chwhite@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Tested-by: Juri Lelli <juri.lelli@redhat.com> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-06-13rtla/hwnoise: Reduce runtime to 75%Gravatar Daniel Bristot de Oliveira 1-1/+7
osnoise runs 100% of time by default. It makes sense because osnoise is preemptive. hwnoise checks preemption once a second, so it reduces system progress. Reduce runtime to 75% to avoid problems by default. I added a Fixes as it might avoid problems for first time users as it lands on distros. Link: https://lkml.kernel.org/r/af0b7113ffc00031b9af4bb40ef5889a27dadf8c.1686066600.git.bristot@kernel.org Cc: William White <chwhite@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Tested-by: Juri Lelli <juri.lelli@redhat.com> Fixes: 1f428356c38d ("rtla: Add hwnoise tool") Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-06-13rtla: Start the tracers after creating all instancesGravatar Daniel Bristot de Oliveira 4-17/+46
Group all start tracing after finishing creating all instances. The tracing instance starts first for the case of hitting a stop tracing while enabling other instances. The trace instance is the one with most valuable information. Link: https://lkml.kernel.org/r/67da7a703a56f75d7cd46568525145a65501a7e8.1686066600.git.bristot@kernel.org Cc: William White <chwhite@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Tested-by: Juri Lelli <juri.lelli@redhat.com> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-06-13rtla/timerlat_hist: Add auto-analysis supportGravatar Daniel Bristot de Oliveira 1-2/+49
Add auto-analysis to timerlat hist, including the --no-aa option to reduce overhead and --dump-task. --aa-only was not added as it is already on timerlat top. Link: https://lkml.kernel.org/r/c2693f47ee83e659a7723fed8035f5d2534f528e.1686066600.git.bristot@kernel.org Cc: William White <chwhite@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Tested-by: Juri Lelli <juri.lelli@redhat.com> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-06-13rtla/timerlat: Give timerlat auto analysis its own instanceGravatar Daniel Bristot de Oliveira 3-21/+67
Currently, the auto-analysis is attached to the timerlat top instance. The idea was to avoid creating another instance just for that, so one instance could be reused. The drawback is that, by doing so, the auto-analysis run for the entire session, consuming CPU time. On my 24 box CPUs for timerlat with a 100 us period consumed 50 % with auto analysis, but only 16 % without. By creating an instance for auto-analysis, we can keep the processing stopped until a stop tracing condition is hit. Once it happens, timerlat auto-analysis can use its own trace instance to parse only the end of the trace. By doing so, auto-analysis stop consuming cpu time when it is not needed. If the --aa-only is passed, the timerlat top instance is reused for auto analysis. Link: https://lkml.kernel.org/r/346b7168c1bae552a415715ec6d23c129a43bdb7.1686066600.git.bristot@kernel.org Cc: William White <chwhite@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Tested-by: Juri Lelli <juri.lelli@redhat.com> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-06-13rtla: Automatically move rtla to a house-keeping cpuGravatar Daniel Bristot de Oliveira 6-0/+87
When the user sets -c <cpu-list> try to move rtla out of the <cpu-list>, even without an -H option. This is useful to avoid having rtla interfering with the workload. This works by removing <cpu-list> from rtla's current affinity. If rtla fails to move itself away it is not that of a problem as this is an automatic measure. Link: https://lkml.kernel.org/r/c54304d90c777310fb85a3e658d1449173759aab.1686066600.git.bristot@kernel.org Cc: William White <chwhite@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Tested-by: Juri Lelli <juri.lelli@redhat.com> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-06-13rtla: Change monitored_cpus from char * to cpu_set_tGravatar Daniel Bristot de Oliveira 5-87/+24
Use a cpumask instead of a char *, reducing memory footprint and code. No functional change, and in preparation for auto house-keeping. Link: https://lkml.kernel.org/r/54c46293261d13cb1042d0314486539eeb45fe5d.1686066600.git.bristot@kernel.org Cc: William White <chwhite@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Tested-by: Juri Lelli <juri.lelli@redhat.com> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-06-13rtla: Add --house-keeping optionGravatar Daniel Bristot de Oliveira 6-9/+162
To avoid having rtla interfering with the measurement threads, add an option for the user to set the CPUs in which rtla should run. For instance: # rtla timerlat top -H 0 -c 1-7 Will place rtla in the CPU 0, while running the measurement threads in the CPU 1-7. Link: https://lkml.kernel.org/r/6a6c78a579a96ba8b02ae67ee1e0ba2cb5e03c4a.1686066600.git.bristot@kernel.org Cc: William White <chwhite@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Tested-by: Juri Lelli <juri.lelli@redhat.com> Suggested-by: Juri Lelli <juri.lelli@redhat.com> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-06-13rtla: Add -C cgroup supportGravatar Daniel Bristot de Oliveira 6-9/+282
The -C option sets a cgroup to the tracer's threads. If the -C option is passed without arguments, the tracer's thread will inherit rtla's cgroup. Otherwise, the threads will be placed on the cgroup passed to the option. Link: https://lkml.kernel.org/r/cb051477331d292f17c08bf1d66f0e0384bbe5a5.1686066600.git.bristot@kernel.org Cc: William White <chwhite@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Tested-by: Juri Lelli <juri.lelli@redhat.com> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-04-25rtla/timerlat: Fix "Previous IRQ" auto analysis' lineGravatar Daniel Bristot de Oliveira 1-1/+1
The "Previous IRQ interference" line is misaligned and without a \n, breaking the tool's output: ## CPU 12 hit stop tracing, analyzing it ## Previous IRQ interference: up to 2.22 us IRQ handler delay: 18.06 us (0.00 %) IRQ latency: 18.52 us Timerlat IRQ duration: 4.41 us (0.00 %) Blocking thread: 216.93 us (0.03 %) Fix the output: ## CPU 7 hit stop tracing, analyzing it ## Previous IRQ interference: up to 8.93 us IRQ handler delay: 0.98 us (0.00 %) IRQ latency: 2.95 us Timerlat IRQ duration: 11.26 us (0.03 %) Link: https://lore.kernel.org/linux-trace-devel/8b5819077f15ccf24745c9bf3205451e16ee32d9.1679685525.git.bristot@kernel.org Fixes: 27e348b221f6 ("rtla/timerlat: Add auto-analysis core") Cc: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-04-25rtla/timerlat: Add auto-analysis only optionGravatar Daniel Bristot de Oliveira 1-5/+44
Parsing and formating timerlat data might consume a reasonable amount of CPU time on very large systems, or when timerlat has a too short period. Add an option to run timerlat with auto-analysis enabled while skipping the statistics parsing. In this mode, rtla timerlat periodically checks if the tracing is on, going to sleep waiting for the stop tracing condition to stop tracing, or for the tracing session to finish. If the stop tracing condition is hit, the tool prints the auto analysis. Otherwise, the tool prints the max observed latency and exit. The max observed latency is captured via tracing_max_latency. Link: https://lore.kernel.org/linux-trace-devel/4dc514d1d5dc353c537a466a9b5af44c266b6da2.1680106912.git.bristot@kernel.org Cc: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-04-25rtla: Add .gitignore fileGravatar Rong Tao 1-0/+1
Add .gitignore file to ignore the rtla binary. Link: https://lore.kernel.org/linux-trace-devel/tencent_3C22A3418CD06196C2E5A84AE3EBC2281206@qq.com Signed-off-by: Rong Tao <rongtao@cestc.cn> Acked-by: Daniel Bristot de Oliveira <bristot@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-02-23Merge tag 'trace-v6.3' of ↵Gravatar Linus Torvalds 1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull tracing updates from Steven Rostedt: - Add function names as a way to filter function addresses - Add sample module to test ftrace ops and dynamic trampolines - Allow stack traces to be passed from beginning event to end event for synthetic events. This will allow seeing the stack trace of when a task is scheduled out and recorded when it gets scheduled back in. - Add trace event helper __get_buf() to use as a temporary buffer when printing out trace event output. - Add kernel command line to create trace instances on boot up. - Add enabling of events to instances created at boot up. - Add trace_array_puts() to write into instances. - Allow boot instances to take a snapshot at the end of boot up. - Allow live patch modules to include trace events - Minor fixes and clean ups * tag 'trace-v6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (31 commits) tracing: Remove unnecessary NULL assignment tracepoint: Allow livepatch module add trace event tracing: Always use canonical ftrace path tracing/histogram: Fix stacktrace histogram Documententation tracing/histogram: Fix stacktrace key tracing/histogram: Fix a few problems with stacktrace variable printing tracing: Add BUILD_BUG() to make sure stacktrace fits in strings tracing/histogram: Don't use strlen to find length of stacktrace variables tracing: Allow boot instances to have snapshot buffers tracing: Add trace_array_puts() to write into instance tracing: Add enabling of events to boot instances tracing: Add creation of instances at boot command line tracing: Fix trace_event_raw_event_synth() if else statement samples: ftrace: Make some global variables static ftrace: sample: avoid open-coded 64-bit division samples: ftrace: Include the nospec-branch.h only for x86 tracing: Acquire buffer from temparary trace sequence tracing/histogram: Wrap remaining shell snippets in code blocks tracing/osnoise: No need for schedule_hrtimeout range bpf/tracing: Use stage6 of tracing to not duplicate macros ...
2023-02-18tracing: Always use canonical ftrace pathGravatar Ross Zwisler 1-1/+1
The canonical location for the tracefs filesystem is at /sys/kernel/tracing. But, from Documentation/trace/ftrace.rst: Before 4.1, all ftrace tracing control files were within the debugfs file system, which is typically located at /sys/kernel/debug/tracing. For backward compatibility, when mounting the debugfs file system, the tracefs file system will be automatically mounted at: /sys/kernel/debug/tracing Many comments and Kconfig help messages in the tracing code still refer to this older debugfs path, so let's update them to avoid confusion. Link: https://lore.kernel.org/linux-trace-kernel/20230215223350.2658616-2-zwisler@google.com Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Reviewed-by: Mukesh Ojha <quic_mojha@quicinc.com> Signed-off-by: Ross Zwisler <zwisler@google.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-02-13rtla: Add hwnoise toolGravatar Daniel Bristot de Oliveira 5-16/+198
The hwnoise tool is a special mode for the osnoise top tool. hwnoise dispatches the osnoise tracer and displays a summary of the noise. The difference is that it runs the tracer with the OSNOISE_IRQ_DISABLE option set, thus only allowing only hardware-related noise, resulting in a simplified output. hwnoise has the same features of osnoise. An example of the tool's output: # rtla hwnoise -c 1-11 -T 1 -d 10m -q Hardware-related Noise duration: 0 00:10:00 | time is in us CPU Period Runtime Noise % CPU Aval Max Noise Max Single HW NMI 1 #599 599000000 138 99.99997 3 3 4 74 2 #599 599000000 85 99.99998 3 3 4 75 3 #599 599000000 86 99.99998 4 3 6 75 4 #599 599000000 81 99.99998 4 4 2 75 5 #599 599000000 85 99.99998 2 2 2 75 Link: https://lkml.kernel.org/r/2d6f49a6f3a4f8b51b2c806458b1cff71ad4d014.1675805361.git.bristot@kernel.org Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org> Cc: Daniel Bristot de Oliveira <bristot@kernel.org> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Clark Williams <williams@redhat.com> Cc: Bagas Sanjaya <bagasdotme@gmail.com> Cc: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-02-02rtla/timerlat: Add auto-analysis support to timerlat topGravatar Daniel Bristot de Oliveira 1-2/+44
Currently, timerlat top displays the timerlat tracer latency results, saving the intuitive timerlat trace for the developer to analyze. This patch goes a step forward in the automaton of the scheduling latency analysis by providing a summary of the root cause of a latency higher than the passed "stop tracing" parameter if the trace stops. The output is intuitive enough for non-expert users to have a general idea of the root cause by looking at each factor's contribution percentage while keeping the technical detail in the output for more expert users to start an in dept debug or to correlate a root cause with an existing one. The terminology is in line with recent industry and academic publications to facilitate the understanding of both audiences. Here is one example of tool output: ----------------------------------------- %< ----------------------------------------------------- # taskset -c 0 timerlat -a 40 -c 1-23 -q Timer Latency 0 00:00:12 | IRQ Timer Latency (us) | Thread Timer Latency (us) CPU COUNT | cur min avg max | cur min avg max 1 #12322 | 0 0 1 15 | 10 3 9 31 2 #12322 | 3 0 1 12 | 10 3 9 23 3 #12322 | 1 0 1 21 | 8 2 8 34 4 #12322 | 1 0 1 17 | 10 2 11 33 5 #12322 | 0 0 1 12 | 8 3 8 25 6 #12322 | 1 0 1 14 | 16 3 11 35 7 #12322 | 0 0 1 14 | 9 2 8 29 8 #12322 | 1 0 1 22 | 9 3 9 34 9 #12322 | 0 0 1 14 | 8 2 8 24 10 #12322 | 1 0 0 12 | 9 3 8 24 11 #12322 | 0 0 0 15 | 6 2 7 29 12 #12321 | 1 0 0 13 | 5 3 8 23 13 #12319 | 0 0 1 14 | 9 3 9 26 14 #12321 | 1 0 0 13 | 6 2 8 24 15 #12321 | 1 0 1 15 | 12 3 11 27 16 #12318 | 0 0 1 13 | 7 3 10 24 17 #12319 | 0 0 1 13 | 11 3 9 25 18 #12318 | 0 0 0 12 | 8 2 8 20 19 #12319 | 0 0 1 18 | 10 2 9 28 20 #12317 | 0 0 0 20 | 9 3 8 34 21 #12318 | 0 0 0 13 | 8 3 8 28 22 #12319 | 0 0 1 11 | 8 3 10 22 23 #12320 | 28 0 1 28 | 41 3 11 41 rtla timerlat hit stop tracing ## CPU 23 hit stop tracing, analyzing it ## IRQ handler delay: 27.49 us (65.52 %) IRQ latency: 28.13 us Timerlat IRQ duration: 9.59 us (22.85 %) Blocking thread: 3.79 us (9.03 %) objtool:49256 3.79 us Blocking thread stacktrace -> timerlat_irq -> __hrtimer_run_queues -> hrtimer_interrupt -> __sysvec_apic_timer_interrupt -> sysvec_apic_timer_interrupt -> asm_sysvec_apic_timer_interrupt -> _raw_spin_unlock_irqrestore -> cgroup_rstat_flush_locked -> cgroup_rstat_flush_irqsafe -> mem_cgroup_flush_stats -> mem_cgroup_wb_stats -> balance_dirty_pages -> balance_dirty_pages_ratelimited_flags -> btrfs_buffered_write -> btrfs_do_write_iter -> vfs_write -> __x64_sys_pwrite64 -> do_syscall_64 -> entry_SYSCALL_64_after_hwframe ------------------------------------------------------------------------ Thread latency: 41.96 us (100%) The system has exit from idle latency! Max timerlat IRQ latency from idle: 17.48 us in cpu 4 Saving trace to timerlat_trace.txt ----------------------------------------- >% ----------------------------------------------------- In this case, the major factor was the delay suffered by the IRQ handler that handles timerlat wakeup: 65.52 %. This can be caused by the current thread masking interrupts, which can be seen in the blocking thread stacktrace: the current thread (objtool:49256) disabled interrupts via raw spin lock operations inside mem cgroup, while doing write syscall in a btrfs file system. A simple search for the function name on Google shows that this is a legit case for disabling the interrupts: cgroup: Use irqsave in cgroup_rstat_flush_locked() lore.kernel.org/linux-mm/20220301122143.1521823-2-bigeasy@linutronix.de/ The output also prints other reasons for the latency root cause, such as: - an IRQ that happened before the IRQ handler that caused delays - The interference from NMI, IRQ, Softirq, and Threads The details about how these factors affect the scheduling latency can be found here: https://bristot.me/demystifying-the-real-time-linux-latency/ Link: https://lkml.kernel.org/r/3d45f40e630317f51ac6d678e2d96d310e495729.1675179318.git.bristot@kernel.org Cc: Daniel Bristot de Oliveira <bristot@kernel.org> Cc: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-02-02rtla/timerlat: Add auto-analysis coreGravatar Daniel Bristot de Oliveira 3-0/+1005
Currently, timerlat displays a summary of the timerlat tracer results saving the trace if the system hits a stop condition. While this represented a huge step forward, the root cause was not that is accessible to non-expert users. The auto-analysis fulfill this gap by parsing the trace timerlat runs, printing an intuitive auto-analysis. Link: https://lkml.kernel.org/r/1ee073822f6a2cbb33da0c817331d0d4045e837f.1675179318.git.bristot@kernel.org Cc: Daniel Bristot de Oliveira <bristot@kernel.org> Cc: Jonathan Corbet <corbet@lwn.net> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-01-31tools/tracing/rtla: osnoise_hist: display average with two-digit precisionGravatar Andreas Ziegler 1-2/+2
Calculate average value in osnoise-hist summary with two-digit precision to avoid displaying too optimitic results. Link: https://lkml.kernel.org/r/20230103103400.275566-3-br015@umbiko.net Signed-off-by: Andreas Ziegler <br015@umbiko.net> Acked-by: Daniel Bristot de Oliveira <bristot@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-01-31tools/tracing/rtla: osnoise_hist: use total duration for average calculationGravatar Andreas Ziegler 1-1/+4
Sampled durations must be weighted by observed quantity, to arrive at a correct average duration value. Perform calculation of total duration by summing (duration * count). Link: https://lkml.kernel.org/r/20230103103400.275566-2-br015@umbiko.net Fixes: 829a6c0b5698 ("rtla/osnoise: Add the hist mode") Signed-off-by: Andreas Ziegler <br015@umbiko.net> Acked-by: Daniel Bristot de Oliveira <bristot@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-12-09rtla: Fix exit status when returning from calls to usage()Gravatar John Kacur 3-17/+13
rtla_usage(), osnoise_usage() and timerlat_usage() all exit with an error status. However when these are called from help, they should exit with a non-error status. Fix this by passing the exit status to the functions. Note, although we remove the subsequent call to exit after calling usage, we leave it in at the end of a function to suppress the compiler warning "control reaches end of a non-void function". Link: https://lkml.kernel.org/r/20221107144313.22470-1-jkacur@redhat.com Signed-off-by: John Kacur <jkacur@redhat.com> Acked-by: Daniel Bristot de Oliveira <bristot@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-08-10rtla: Consolidate and show all necessary libraries that failed for buildingGravatar Steven Rostedt (Google) 1-26/+36
When building rtla tools, if the necessary libraries are not installed (libtraceevent and libtracefs), show the ones that are missing in one consolidated output, and also show how to install them (at least for Fedora). Link: https://lore.kernel.org/all/CAHk-=wh+e1qcCnEYJ3JRDVLNCYbJ=0u+Ts5bOYZnY3mX_k-hFA@mail.gmail.com/ Link: https://lkml.kernel.org/r/20220810113918.5d19ce59@gandalf.local.home Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-08-10tools/rtla: Build with EXTRA_{C,LD}FLAGSGravatar Ben Hutchings 1-2/+2
To allow for distributions and other builders to apply hardening policy and other customisation, append EXTRA_CFLAGS and EXTRA_LDFLAGS to the corresponding variables. Link: https://lore.kernel.org/linux-trace-devel/YtLBshz0nMQ7530H@decadent.org.uk Signed-off-by: Ben Hutchings <benh@debian.org> Acked-by: Daniel Bristot de Oliveira <bristot@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-08-10tools/rtla: Fix command symlinksGravatar Ben Hutchings 1-2/+2
"ln -s" stores the next argument directly as the symlink target, so it needs to be a relative path. In this case, just "rtla". Link: https://lore.kernel.org/linux-trace-devel/YtLBXMI6Ui4HLIF1@decadent.org.uk Fixes: 0605bf009f18 ("rtla: Add osnoise tool") Fixes: a828cd18bc4a ("rtla: Add timerlat tool and timelart top mode") Signed-off-by: Ben Hutchings <benh@debian.org> Acked-by: Daniel Bristot de Oliveira <bristot@kernel.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-08-10rtla: Fix tracer nameGravatar Alexandre Vicenzi 2-2/+2
The correct tracer name is timerlat and not timelat. Link: https://lore.kernel.org/linux-trace-devel/20220808180343.22262-1-alexandre.vicenzi@suse.com Signed-off-by: Alexandre Vicenzi <alexandre.vicenzi@suse.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Copyright © 1990 – 2022 jet tsang zeon-git.
All Rights Reverse Engineered.