> Il giorno 9 apr 2020, alle ore 19:09, Jan Kara <jack@xxxxxxx> ha scritto:
>
> Currently queues that have average think time shorter than slice_idle
> cannot have waker. However this requirement is too strict. E.g. dbench
> process always submits a one or two IOs (which is enough to pull its
> average think time below slice_idle) and then blocks waiting for jbd2
> thread to commit a transaction. Due to idling logic jbd2 thread is
> often forced to wait for dbench's idle timer to trigger to be able to
> submit its IO and this severely delays the overall benchmark progress.
>
> E.g. on my test machine current dbench single-thread throughput is ~80
> MB/s, with this patch it is ~200 MB/s.
>
Hi Jan,
I've modified this logic a little bit (in patches that I'm going to
submit). And I don't see your boost in my tests. So it's difficult
for me to validate this change. If ok for you, you could test it on
top of the patches that I'll submit. If you see a boost, and (as I
expect) I won't see any regression, this improvement is very welcome
for me.
Thanks,
Paolo
> Signed-off-by: Jan Kara <jack@xxxxxxx>
> ---
> block/bfq-iosched.c | 1 -
> 1 file changed, 1 deletion(-)
>
> diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c
> index 18f85d474c9c..416473ba80c8 100644
> --- a/block/bfq-iosched.c
> +++ b/block/bfq-iosched.c
> @@ -1928,7 +1928,6 @@ static void bfq_add_request(struct request *rq)
> * I/O-plugging interval for bfqq.
> */
> if (bfqd->last_completed_rq_bfqq &&
> - !bfq_bfqq_has_short_ttime(bfqq) &&
> ktime_get_ns() - bfqd->last_completion <
> 200 * NSEC_PER_USEC) {
> if (bfqd->last_completed_rq_bfqq != bfqq &&
> --
> 2.16.4
>
