From: Mike Snitzer <snitzer@redhat.com>
To: Jens Axboe <axboe@kernel.dk>, Omar Sandoval <osandov@fb.com>
Cc: linux-block@vger.kernel.org, dm-devel@redhat.com,
Mikulas Patocka <mpatocka@redhat.com>
Subject: Re: [PATCH v4 0/7] per-cpu in_flight counters for bio-based drivers
Date: Thu, 6 Dec 2018 14:04:45 -0500 [thread overview]
Message-ID: <20181206190444.GA15753@redhat.com> (raw)
In-Reply-To: <20181206180025.GA15514@redhat.com>
On Thu, Dec 06 2018 at 1:00pm -0500,
Mike Snitzer <snitzer@redhat.com> wrote:
> On Thu, Dec 06 2018 at 11:41am -0500,
> Mike Snitzer <snitzer@redhat.com> wrote:
>
> > Hey,
> >
> > This v4 addresses the compile issues on various archs when CONFIG_SMP
> > isn't set (by introducing appropriate wrappers in genhd.h)
> >
> > Testing with this v4 I was unable to reproduce the issue you reported
> > where iostat always reports 0 for avgqu-sz -- but please let me know
> > if you still see problems like that.
>
> I ran blktests and both block/017 and block/018 fail due to this
> patchset's changes, I'm still trying to grok what the test result is
> _saying_ but I'll hopefully get there soon:
>
> block/017 (do I/O and check the inflight counter) [failed]
> runtime ... 77.675s
> --- tests/block/017.out 2018-12-06 12:31:21.457936217 -0500
> +++ /home/git/blktests/results/nodev/block/017.out.bad 2018-12-06 12:36:15.735053586 -0500
> @@ -1,14 +1,14 @@
> Running block/017
> -sysfs inflight reads 1
> +sysfs inflight reads 2
> sysfs inflight writes 0
> -sysfs stat 1
> -diskstats 1
> -sysfs inflight reads 1
> ...
> (Run 'diff -u tests/block/017.out /home/git/blktests/results/nodev/block/017.out.bad' to see the entire diff)
>
> # diff -u tests/block/017.out /home/git/blktests/results/nodev/block/017.out.bad
> --- tests/block/017.out 2018-12-06 12:31:21.457936217 -0500
> +++ /home/git/blktests/results/nodev/block/017.out.bad 2018-12-06 12:51:36.695542332 -0500
> @@ -1,14 +1,14 @@
> Running block/017
> -sysfs inflight reads 1
> +sysfs inflight reads 2
> sysfs inflight writes 0
> -sysfs stat 1
> -diskstats 1
> -sysfs inflight reads 1
> -sysfs inflight writes 1
> sysfs stat 2
> diskstats 2
> -sysfs inflight reads 0
> +sysfs inflight reads 2
> +sysfs inflight writes 1
> +sysfs stat 3
> +diskstats 3
> +sysfs inflight reads 1
> sysfs inflight writes 0
> -sysfs stat 0
> -diskstats 0
> +sysfs stat 1
> +diskstats 1
> Test complete
>
Interestingly the 017 test is only testing blk-mq (using null_blk's
queue_mode=2). This patchset's changes are specific to bio-based.
If I revert this patchset I still get the failures.
So it would seem something regressed in latest block for-next (I've been
testing up through linux-block commit c754a9bf7ee8 ("blk-mq: remove
QUEUE_FLAG_POLL from default MQ flags").
> block/018 (do I/O and check iostats times) [failed]
> runtime ... 156.073s
> --- tests/block/018.out 2018-12-06 12:31:21.458936217 -0500
> +++ /home/git/blktests/results/nodev/block/018.out.bad 2018-12-06 12:38:51.831116369 -0500
> @@ -1,10 +1,10 @@
> Running block/018
> read 0 s
> write 0 s
> -read 1 s
> +read 2 s
> write 0 s
> -read 1 s
> ...
> (Run 'diff -u tests/block/018.out /home/git/blktests/results/nodev/block/018.out.bad' to see the entire diff)
>
> # diff -u tests/block/018.out /home/git/blktests/results/nodev/block/018.out.bad
> --- tests/block/018.out 2018-12-06 12:31:21.458936217 -0500
> +++ /home/git/blktests/results/nodev/block/018.out.bad 2018-12-06 12:38:51.831116369 -0500
> @@ -1,10 +1,10 @@
> Running block/018
> read 0 s
> write 0 s
> -read 1 s
> +read 2 s
> write 0 s
> -read 1 s
> -write 1 s
> read 2 s
> +write 1 s
> +read 6 s
> write 3 s
> Test complete
Same goes for this block/018 test.
Mike
next prev parent reply other threads:[~2018-12-06 19:04 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-12-06 16:41 [PATCH v4 0/7] per-cpu in_flight counters for bio-based drivers Mike Snitzer
2018-12-06 16:41 ` [PATCH v4 1/7] dm: dont rewrite dm_disk(md)->part0.in_flight Mike Snitzer
2018-12-06 16:41 ` [PATCH v4 2/7] dm rq: leverage blk_mq_queue_busy() to check for outstanding IO Mike Snitzer
2018-12-06 16:41 ` [PATCH v4 3/7] block: stop passing 'cpu' to all percpu stats methods Mike Snitzer
2018-12-06 16:41 ` [PATCH v4 4/7] block: delete part_round_stats and switch to less precise counting Mike Snitzer
2018-12-06 16:41 ` [PATCH v4 5/7] block: switch to per-cpu in-flight counters Mike Snitzer
2018-12-06 16:41 ` [PATCH v4 6/7] block: return just one value from part_in_flight Mike Snitzer
2018-12-06 16:41 ` [PATCH v4 7/7] dm: remove the pending IO accounting Mike Snitzer
2018-12-06 18:00 ` [PATCH v4 0/7] per-cpu in_flight counters for bio-based drivers Mike Snitzer
2018-12-06 19:04 ` Mike Snitzer [this message]
2018-12-10 15:35 ` Jens Axboe
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