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| author |  Jens Axboe <axboe@kernel.dk>
| 2023-02-15 16:43:47 -0700 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk>
| 2023-02-16 10:02:55 -0700 |
| commit | 67205f80be9910207481406c47f7d85e703fb2e9 (patch) | |
| tree | e7b53cfc2ba0eca7b6a7326814484529414e3b85 /block/blk-core.c | |
| parent | brd: check for REQ_NOWAIT and set correct page allocation mask (diff) | |
| download | linux-67205f80be9910207481406c47f7d85e703fb2e9.tar.gz linux-67205f80be9910207481406c47f7d85e703fb2e9.tar.bz2 linux-67205f80be9910207481406c47f7d85e703fb2e9.zip | |
brd: mark as nowait compatible
By default, non-mq drivers do not support nowait. This causes io_uring
to use a slower path as the driver cannot be trust not to block. brd
can safely set the nowait flag, as worst case all it does is a NOIO
allocation.
For io_uring, this makes a substantial difference. Before:
submitter=0, tid=453, file=/dev/ram0, node=-1
polled=0, fixedbufs=1/0, register_files=1, buffered=0, QD=128
Engine=io_uring, sq_ring=128, cq_ring=128
IOPS=440.03K, BW=1718MiB/s, IOS/call=32/31
IOPS=428.96K, BW=1675MiB/s, IOS/call=32/32
IOPS=442.59K, BW=1728MiB/s, IOS/call=32/31
IOPS=419.65K, BW=1639MiB/s, IOS/call=32/32
IOPS=426.82K, BW=1667MiB/s, IOS/call=32/31
and after:
submitter=0, tid=354, file=/dev/ram0, node=-1
polled=0, fixedbufs=1/0, register_files=1, buffered=0, QD=128
Engine=io_uring, sq_ring=128, cq_ring=128
IOPS=3.37M, BW=13.15GiB/s, IOS/call=32/31
IOPS=3.45M, BW=13.46GiB/s, IOS/call=32/31
IOPS=3.43M, BW=13.42GiB/s, IOS/call=32/32
IOPS=3.43M, BW=13.39GiB/s, IOS/call=32/31
IOPS=3.43M, BW=13.38GiB/s, IOS/call=32/31
or about an 8x in difference. Now that brd is prepared to deal with
REQ_NOWAIT reads/writes, mark it as supporting that.
Cc: stable@vger.kernel.org # 5.10+
Link: https://lore.kernel.org/linux-block/20230203103005.31290-1-p.raghav@samsung.com/
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block/blk-core.c')
0 files changed, 0 insertions, 0 deletions