From: Valentin Schneider <valentin.schneider@arm.com> To: Josef Bacik <josef@toxicpanda.com> Cc: Thorsten Leemhuis <regressions@leemhuis.info>, 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: Thu, 13 Jan 2022 16:41:57 +0000 [thread overview] Message-ID: <87k0f37fl6.mognet@arm.com> (raw) In-Reply-To: <YdMhQRq1K8tW+S05@localhost.localdomain> On 03/01/22 11:16, Josef Bacik wrote: > On Wed, Dec 22, 2021 at 04:07:35PM +0000, Valentin Schneider wrote: >> >> 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? > > Sorry, holidays and all that. I see 0 difference between the two commits, and > no regression from baseline. It'll take me a few days to recover from the > holidays, but I'll put some more effort into actively debugging wtf is going on > here on my side since we're all having trouble pinning down what's going > on. Humph, that's unfortunate... I just came back from my holidays, so I'll be untangling my inbox for the next few days. Do keep us posted! > Thanks, > > Josef
next prev parent reply other threads:[~2022-01-13 16:42 UTC|newest] Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-11-29 17:03 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 2022-01-03 16:16 ` Josef Bacik 2022-01-13 16:41 ` Valentin Schneider [this message] 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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