linux-kernel - Re: [RFC PATCH v8] sched: Fix performance regression introduced by mm

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <40689cd1-af60-542d-2245-c6362c73a365@efficios.com>
Date:   Tue, 18 Apr 2023 12:01:09 -0400
From:   Mathieu Desnoyers <mathieu.desnoyers@...icios.com>
To:     Aaron Lu <aaron.lu@...el.com>
Cc:     Peter Zijlstra <peterz@...radead.org>,
        linux-kernel@...r.kernel.org, Olivier Dion <odion@...icios.com>,
        michael.christie@...cle.com
Subject: Re: [RFC PATCH v8] sched: Fix performance regression introduced by
 mm_cid

On 2023-04-18 07:21, Aaron Lu wrote:
> On Mon, Apr 17, 2023 at 11:08:31AM -0400, Mathieu Desnoyers wrote:
>> Introduce per-mm/cpu current concurrency id (mm_cid) to fix a PostgreSQL
>> sysbench regression reported by Aaron Lu.
> 
> For postgres_sysbench on SPR:
> sched_mm_cid_migrate_to() is in the range of 0.1x% - 0.4x%, mm_cid_get()
> is in the range of 0.1x% - 0.3x%. Other cid functions are pretty minor.
> 
> For hackbench on SPR:
> ched_mm_cid_migrate_to() is about 3%-4%, mm_cid_get() is about 7%-8%,
> other cid functions are pretty minor.

It's a bit higher than I would have expected for hackbench.

Can you run with the attached schedstats patch applied and boot
with schedstats=enable ? Let me know how the counters behave please,
because I cannot reproduce anything unexpected on my machine.

Thanks,

Mathieu

-- 
Mathieu Desnoyers
EfficiOS Inc.
https://www.efficios.com

View attachment "schedstat-mm-cid.patch" of type "text/x-patch" (5059 bytes)