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| author |  Mikulas Patocka <mpatocka@redhat.com>
| 2018-12-06 11:41:19 -0500 |
|---|---|---|
| committer |  Jens Axboe <axboe@kernel.dk>
| 2018-12-10 08:30:37 -0700 |
| commit | 5b18b5a737600fd20ba2045f320d5926ebbf341a (patch) | |
| tree | fe35e150bf36785dfe3ed8c845e3b043e56f9f90 /sound | |
| parent | block: stop passing 'cpu' to all percpu stats methods (diff) | |
| download | linux-5b18b5a73760.tar.gz linux-5b18b5a73760.tar.bz2 linux-5b18b5a73760.zip | |
block: delete part_round_stats and switch to less precise counting
We want to convert to per-cpu in_flight counters.
The function part_round_stats needs the in_flight counter every jiffy, it
would be too costly to sum all the percpu variables every jiffy, so it
must be deleted. part_round_stats is used to calculate two counters -
time_in_queue and io_ticks.
time_in_queue can be calculated without part_round_stats, by adding the
duration of the I/O when the I/O ends (the value is almost as exact as the
previously calculated value, except that time for in-progress I/Os is not
counted).
io_ticks can be approximated by increasing the value when I/O is started
or ended and the jiffies value has changed. If the I/Os take less than a
jiffy, the value is as exact as the previously calculated value. If the
I/Os take more than a jiffy, io_ticks can drift behind the previously
calculated value.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'sound')
0 files changed, 0 insertions, 0 deletions