Re: [PATCH v9 rebase on mm-unstable 0/8] Reduce tlb and interrupt numbers over 90% by improving folio migration

From: Andrew Morton
Date: Thu Apr 18 2024 - 16:18:05 EST


On Thu, 18 Apr 2024 15:15:28 +0900 Byungchul Park <byungchul@xxxxxx> wrote:

> $ time XSBench -t 16 -p 50000000
>
> BEFORE
> ------
> Threads: 16
> Runtime: 968.783 seconds
> Lookups: 1,700,000,000
> Lookups/s: 1,754,778
>
> 15208.91s user 141.44s system 1564% cpu 16:20.98 total
>
> AFTER
> -----
> Threads: 16
> Runtime: 913.210 seconds
> Lookups: 1,700,000,000
> Lookups/s: 1,861,565
>
> 14351.69s user 138.23s system 1565% cpu 15:25.47 total

Well that's nice. What exactly is XSBench doing in this situation?
What sort of improvements can we expect to see in useful workloads?

I see it no longer consumes an additional page flag, good.

The patches show no evidence of review activity and I'm not seeing much
on the mailing list (patchset title was changed. Previous title
"Reduce TLB flushes under some specific conditions"). Perhaps a better
description of the overall benefit to our users would help to motivate
reviewers.