diff options
| author | Xue He <xue01.he@samsung.com> | 2025-11-18 07:32:30 +0000 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2025-11-18 14:59:41 -0700 |
| commit | 152c331bcd805eddd520979c51cea46582e260fc (patch) | |
| tree | ccb5a1dd26e6174d51ca03d3b3b7c4b4b3ea428a /block | |
| parent | f43fdeb9a368a5ff56b088b46edc245bd4b52cde (diff) | |
block: plug attempts to batch allocate tags multiple times
This patch aims to enable batch allocation of sufficient tags after
batch IO submission with plug mechanism, thereby avoiding the need for
frequent individual requests when the initial allocation is
insufficient.
-----------------------------------------------------------
HW:
16 CPUs/16 poll queues
Disk: Samsung PM9A3 Gen4 3.84T
CMD:
[global]
ioengine=io_uring
group_reporting=1
time_based=1
runtime=1m
refill_buffers=1
norandommap=1
randrepeat=0
fixedbufs=1
registerfiles=1
rw=randread
iodepth=128
iodepth_batch_submit=32
iodepth_batch_complete_min=32
iodepth_batch_complete_max=128
iodepth_low=32
bs=4k
numjobs=1
direct=1
hipri=1
[job1]
filename=/dev/nvme0n1
name=batch_test
------------------------------------------------------------
Perf:
base code: __blk_mq_alloc_requests() 1.47%
patch: __blk_mq_alloc_requests() 0.75%
------------------------------------------------------------
Signed-off-by: hexue <xue01.he@samsung.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block')
| -rw-r--r-- | block/blk-mq.c | 33 |
1 files changed, 19 insertions, 14 deletions
diff --git a/block/blk-mq.c b/block/blk-mq.c index 0d38daaa4705..f2650c97a75e 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -468,21 +468,26 @@ __blk_mq_alloc_requests_batch(struct blk_mq_alloc_data *data) unsigned long tag_mask; int i, nr = 0; - tag_mask = blk_mq_get_tags(data, data->nr_tags, &tag_offset); - if (unlikely(!tag_mask)) - return NULL; + do { + tag_mask = blk_mq_get_tags(data, data->nr_tags - nr, &tag_offset); + if (unlikely(!tag_mask)) { + if (nr == 0) + return NULL; + break; + } + tags = blk_mq_tags_from_data(data); + for (i = 0; tag_mask; i++) { + if (!(tag_mask & (1UL << i))) + continue; + tag = tag_offset + i; + prefetch(tags->static_rqs[tag]); + tag_mask &= ~(1UL << i); + rq = blk_mq_rq_ctx_init(data, tags, tag); + rq_list_add_head(data->cached_rqs, rq); + nr++; + } + } while (data->nr_tags > nr); - tags = blk_mq_tags_from_data(data); - for (i = 0; tag_mask; i++) { - if (!(tag_mask & (1UL << i))) - continue; - tag = tag_offset + i; - prefetch(tags->static_rqs[tag]); - tag_mask &= ~(1UL << i); - rq = blk_mq_rq_ctx_init(data, tags, tag); - rq_list_add_head(data->cached_rqs, rq); - nr++; - } if (!(data->rq_flags & RQF_SCHED_TAGS)) blk_mq_add_active_requests(data->hctx, nr); /* caller already holds a reference, add for remainder */ |