| From: |
| Ingo Molnar <mingo-AT-kernel.org> |
| To: |
| Ankur Arora <ankur.a.arora-AT-oracle.com> |
| Subject: |
| Re: [PATCH v3 0/4] mm/folio_zero_user: add multi-page clearing |
| Date: |
| Mon, 14 Apr 2025 08:36:18 +0200 |
| Message-ID: |
| <Z_ys4jJ8MQ4-kW8P@gmail.com> |
| Cc: |
| linux-kernel-AT-vger.kernel.org, linux-mm-AT-kvack.org, x86-AT-kernel.org, torvalds-AT-linux-foundation.org, akpm-AT-linux-foundation.org, bp-AT-alien8.de, dave.hansen-AT-linux.intel.com, hpa-AT-zytor.com, mingo-AT-redhat.com, luto-AT-kernel.org, peterz-AT-infradead.org, paulmck-AT-kernel.org, rostedt-AT-goodmis.org, tglx-AT-linutronix.de, willy-AT-infradead.org, jon.grimm-AT-amd.com, bharata-AT-amd.com, raghavendra.kt-AT-amd.com, boris.ostrovsky-AT-oracle.com, konrad.wilk-AT-oracle.com |
| Archive-link: |
| Article |
* Ankur Arora <ankur.a.arora@oracle.com> wrote:
> We also see performance improvement for cases where this optimization is
> unavailable (pg-sz=2MB on AMD, and pg-sz=2MB|1GB on Intel) because
> REP; STOS is typically microcoded which can now be amortized over
> larger regions and the hint allows the hardware prefetcher to do a
> better job.
>
> Milan (EPYC 7J13, boost=0, preempt=full|lazy):
>
> mm/folio_zero_user x86/folio_zero_user change
> (GB/s +- stddev) (GB/s +- stddev)
>
> pg-sz=1GB 16.51 +- 0.54% 42.80 +- 3.48% + 159.2%
> pg-sz=2MB 11.89 +- 0.78% 16.12 +- 0.12% + 35.5%
>
> Icelakex (Platinum 8358, no_turbo=1, preempt=full|lazy):
>
> mm/folio_zero_user x86/folio_zero_user change
> (GB/s +- stddev) (GB/s +- stddev)
>
> pg-sz=1GB 8.01 +- 0.24% 11.26 +- 0.48% + 40.57%
> pg-sz=2MB 7.95 +- 0.30% 10.90 +- 0.26% + 37.10%
How was this measured? Could you integrate this measurement as a new
tools/perf/bench/ subcommand so that people can try it on different
systems, etc.? There's already a 'perf bench mem' subcommand space
where this feature could be added to.
Thanks,
Ingo
