From f70ced09170761acb69840cafaace4abc72cba4b Mon Sep 17 00:00:00 2001 From: Ming Lei Date: Thu, 25 Sep 2014 23:23:47 +0800 Subject: blk-mq: support per-distpatch_queue flush machinery This patch supports to run one single flush machinery for each blk-mq dispatch queue, so that: - current init_request and exit_request callbacks can cover flush request too, then the buggy copying way of initializing flush request's pdu can be fixed - flushing performance gets improved in case of multi hw-queue In fio sync write test over virtio-blk(4 hw queues, ioengine=sync, iodepth=64, numjobs=4, bs=4K), it is observed that througput gets increased a lot over my test environment: - throughput: +70% in case of virtio-blk over null_blk - throughput: +30% in case of virtio-blk over SSD image The multi virtqueue feature isn't merged to QEMU yet, and patches for the feature can be found in below tree: git://kernel.ubuntu.com/ming/qemu.git v2.1.0-mq.4 And simply passing 'num_queues=4 vectors=5' should be enough to enable multi queue(quad queue) feature for QEMU virtio-blk. Suggested-by: Christoph Hellwig Signed-off-by: Ming Lei Signed-off-by: Jens Axboe --- block/blk-core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'block/blk-core.c') diff --git a/block/blk-core.c b/block/blk-core.c index b1dd4e086740..e1c2775c7597 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -704,7 +704,7 @@ blk_init_allocated_queue(struct request_queue *q, request_fn_proc *rfn, if (!q) return NULL; - q->fq = blk_alloc_flush_queue(q); + q->fq = blk_alloc_flush_queue(q, NUMA_NO_NODE, 0); if (!q->fq) return NULL; -- cgit v1.2.3