From: Valentin Schneider <valentin.schneider@arm.com>
To: Thorsten Leemhuis <regressions@leemhuis.info>,
Josef Bacik <josef@toxicpanda.com>
Cc: peterz@infradead.org, vincent.guittot@linaro.org,
torvalds@linux-foundation.org, linux-kernel@vger.kernel.org,
linux-btrfs@vger.kernel.org, guro@fb.com, clm@fb.com
Subject: Re: [REGRESSION] 5-10% increase in IO latencies with nohz balance patch
Date: Wed, 22 Dec 2021 16:07:35 +0000 [thread overview]
Message-ID: <87tuf07hdk.mognet@arm.com> (raw)
In-Reply-To: <99452126-661e-9a0c-6b51-d345ed0f76ee@leemhuis.info>
Hi,
On 22/12/21 13:42, Thorsten Leemhuis wrote:
> What's the status here? Just wondering, because there hasn't been any
> activity in this thread since 11 days and the festive season is upon us.
>
> Was the discussion moved elsewhere? Or is this still a mystery? And if
> it is: how bad is it, does it need to be fixed before Linus releases 5.16?
>
I got to the end of bisect #3 yesterday, the incriminated commit doesn't
seem to make much sense but I've just re-tested it and there is a clear
regression between that commit and its parent (unlike bisect #1 and #2):
2127d22509aec3a83dffb2a3c736df7ba747a7ce mm, slub: fix two bugs in slab_debug_trace_open()
write_clat_ns_p99 195395.92 199638.20 4797.01 2.17%
write_iops 17305.79 17188.24 250.66 -0.68%
write_clat_ns_p99 195543.84 199996.70 5122.88 2.28%
write_iops 17300.61 17241.86 251.56 -0.34%
write_clat_ns_p99 195543.84 200724.48 5122.88 2.65%
write_iops 17300.61 17246.63 251.56 -0.31%
write_clat_ns_p99 195543.84 200445.41 5122.88 2.51%
write_iops 17300.61 17215.47 251.56 -0.49%
6d2aec9e123bb9c49cb5c7fc654f25f81e688e8c mm/mempolicy: do not allow illegal MPOL_F_NUMA_BALANCING | MPOL_LOCAL in mbind()
write_clat_ns_p99 195395.92 197942.30 4797.01 1.30%
write_iops 17305.79 17246.56 250.66 -0.34%
write_clat_ns_p99 195543.84 196183.92 5122.88 0.33%
write_iops 17300.61 17310.33 251.56 0.06%
write_clat_ns_p99 195543.84 196990.71 5122.88 0.74%
write_iops 17300.61 17346.32 251.56 0.26%
write_clat_ns_p99 195543.84 196362.24 5122.88 0.42%
write_iops 17300.61 17315.71 251.56 0.09%
It's pure debug stuff and AFAICT is a correct fix...
@Josef, could you test that on your side?
> Ciao, Thorsten
>
next prev parent reply other threads:[~2021-12-22 16:07 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-29 17:03 [REGRESSION] 5-10% increase in IO latencies with nohz balance patch Josef Bacik
2021-11-29 18:03 ` Valentin Schneider
2021-11-29 18:15 ` Josef Bacik
2021-11-29 18:31 ` Valentin Schneider
2021-11-29 19:49 ` Josef Bacik
2021-11-30 0:26 ` Valentin Schneider
2021-12-03 12:03 ` Valentin Schneider
2021-12-03 19:00 ` Josef Bacik
2021-12-06 9:48 ` Valentin Schneider
2021-12-09 17:22 ` Valentin Schneider
2021-12-09 19:16 ` Josef Bacik
2021-12-22 12:42 ` Thorsten Leemhuis
2021-12-22 16:07 ` Valentin Schneider [this message]
2022-01-03 16:16 ` Josef Bacik
2022-01-13 16:41 ` Valentin Schneider
2022-01-13 16:57 ` Roman Gushchin
2022-02-18 11:00 ` Thorsten Leemhuis
2022-02-18 15:34 ` Josef Bacik
2021-11-30 7:16 ` Thorsten Leemhuis
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