diff options
| 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 /drivers/block/brd.c | |
| parent | 6ded703c56c21bfb259725d4f1831a5feb563e9b (diff) | |
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 'drivers/block/brd.c')
| -rw-r--r-- | drivers/block/brd.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/block/brd.c b/drivers/block/brd.c index 00f3c5b51a01..740631dcdd0e 100644 --- a/drivers/block/brd.c +++ b/drivers/block/brd.c @@ -418,6 +418,7 @@ static int brd_alloc(int i) /* Tell the block layer that this is not a rotational device */ blk_queue_flag_set(QUEUE_FLAG_NONROT, disk->queue); blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, disk->queue); + blk_queue_flag_set(QUEUE_FLAG_NOWAIT, disk->queue); err = add_disk(disk); if (err) goto out_cleanup_disk; |