On 2011-04-18 20:32, Bart Van Assche wrote: > On Mon, Apr 18, 2011 at 8:28 PM, Jens Axboe <jaxboe@xxxxxxxxxxxx> wrote: >> On 2011-04-18 20:21, Bart Van Assche wrote: >>> a performance regression in the block layer not related to the md >>> issue. If I run a small block IOPS test on a block device created by >>> ib_srp (NOOP scheduler) I see about 11% less IOPS than with 2.6.38.3 >>> (155.000 IOPS with 2.6.38.3 and 140.000 IOPS with 2.6.39-rc3+). >> >> That's not good. What's the test case? > > Nothing more than a fio IOPS test: > > fio --bs=512 --ioengine=libaio --buffered=0 --rw=read --thread > --iodepth=64 --numjobs=2 --loops=10000 --group_reporting --size=1G > --gtod_reduce=1 --name=iops-test --filename=/dev/${dev} --invalidate=1 Bart, can you try the below: diff --git a/block/blk-core.c b/block/blk-core.c index 5fa3dd2..9b41da1 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -307,11 +307,7 @@ void __blk_run_queue(struct request_queue *q) * Only recurse once to avoid overrunning the stack, let the unplug * handling reinvoke the handler shortly if we already got there. */ - if (!queue_flag_test_and_set(QUEUE_FLAG_REENTER, q)) { - q->request_fn(q); - queue_flag_clear(QUEUE_FLAG_REENTER, q); - } else - queue_delayed_work(kblockd_workqueue, &q->delay_work, 0); + q->request_fn(q); } EXPORT_SYMBOL(__blk_run_queue); -- Jens Axboe -- To unsubscribe from this list: send the line "unsubscribe kernel-testers" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html