ptf-threads on mm-unstable seems to regressed from 6.2-rc3

ptf-threads on mm-unstable seems to regressed from 6.2-rc3

[Suren Baghdasaryan]

Hi Andrew and Mel,
While testing per-vma locks on mm-unstable branch I noticed a sizable
regression when running pft-threads test from Mel's mmtests suite:


BASE             MM_UNSTABLE
Hmean     faults/sec-1    469201.7282 (   0.00%)   305002.3892 * -35.00%*
Hmean     faults/sec-4   1754465.6221 (   0.00%)  1183736.3124 * -32.53%*
Hmean     faults/sec-7   2808141.6711 (   0.00%)  1964469.4590 * -30.04%*
Hmean     faults/sec-12  3750307.7553 (   0.00%)  2811359.5393 * -25.04%*
Hmean     faults/sec-21  4145672.4677 (   0.00%)  3082305.9582 * -25.65%*
Hmean     faults/sec-30  3775722.5726 (   0.00%)  2918088.2083 * -22.71%*
Hmean     faults/sec-48  4152563.5864 (   0.00%)  3219418.0414 * -22.47%*
Hmean     faults/sec-56  4163868.7111 (   0.00%)  3124612.3198 * -24.96%*

This is comparing mm-unstable ToT (c04e06325f11 "mm: multi-gen LRU:
simplify lru_gen_look_around()") with 6.2-rc3, which was my previous
baseline (both are tested without my patchset). Not sure if this is
expected, so sending a warning. If this is unexpected, it would also
be great if someone can confirm this is not a fluke on my side.

The test machine I use is a NUMA 2-socket Intel Xeon E5-2690-v4
(Broadwell microarchitecture).
Command I used to reproduce is:
run-mmtests.sh --no-monitor --config configs/config-workload-pft-threads <name>
Thanks,
Suren.

Re: ptf-threads on mm-unstable seems to regressed from 6.2-rc3

[T.J. Alumbaugh]

Hi Suren,

On Sun, Jan 22, 2023 at 12:28 AM Suren Baghdasaryan <surenb@google.com> wrote:

> This is comparing mm-unstable ToT (c04e06325f11 "mm: multi-gen LRU:
> simplify lru_gen_look_around()") with 6.2-rc3, which was my previous
> baseline (both are tested without my patchset). Not sure if this is
> expected, so sending a warning. If this is unexpected, it would also
> be great if someone can confirm this is not a fluke on my side.

I don't believe this is caused by MGLRU, but I think knowing that
would help bisect the regression. Can you confirm that MGLRU is not
enabled for those results?

Thanks,
-T.J.

Re: ptf-threads on mm-unstable seems to regressed from 6.2-rc3

[Suren Baghdasaryan]

On Sun, Jan 22, 2023 at 10:53 AM T.J. Alumbaugh <talumbau@google.com> wrote:
>
> Hi Suren,
>
> On Sun, Jan 22, 2023 at 12:28 AM Suren Baghdasaryan <surenb@google.com> wrote:
>
> > This is comparing mm-unstable ToT (c04e06325f11 "mm: multi-gen LRU:
> > simplify lru_gen_look_around()") with 6.2-rc3, which was my previous
> > baseline (both are tested without my patchset). Not sure if this is
> > expected, so sending a warning. If this is unexpected, it would also
> > be great if someone can confirm this is not a fluke on my side.

Sorry, false alert. I found the reason for regression is the
CONFIG_KASAN which was enabled in one case and disabled in the other.

>
> I don't believe this is caused by MGLRU, but I think knowing that
> would help bisect the regression. Can you confirm that MGLRU is not
> enabled for those results?

CONFIG_LRU_GEN was not set in both cases.

Sorry for the noise.
Thanks,
Suren.

>
> Thanks,
> -T.J.