linux-kernel - Re: [linus:master] [sched/mmcid] 77d7dc8bef: will-it-scale.per_thread

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Message-ID: <2db4150b-2608-409c-8d15-ced64964c2c5@efficios.com>
Date: Tue, 6 Jan 2026 08:39:43 -0500
From: Mathieu Desnoyers <mathieu.desnoyers@...icios.com>
To: kernel test robot <oliver.sang@...el.com>,
 Thomas Gleixner <tglx@...utronix.de>
Cc: oe-lkp@...ts.linux.dev, lkp@...el.com, linux-kernel@...r.kernel.org,
 Peter Zijlstra <peterz@...radead.org>, linux-mm@...ck.org,
 aubrey.li@...ux.intel.com, yu.c.chen@...el.com
Subject: Re: [linus:master] [sched/mmcid] 77d7dc8bef:
 will-it-scale.per_thread_ops 10.4% regression

On 2026-01-05 21:15, kernel test robot wrote:
[...]
> now we found a regression in will-it-scale tests. report again FYI the
> performance impact of this change in our tests.
> 
> 
> kernel test robot noticed a 10.4% regression of will-it-scale.per_thread_ops on:
> 
> 
> commit: 77d7dc8bef482e987036bc204136bbda552d95cd ("sched/mmcid: Revert the complex CID management")
> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git master

This is expected for this preparation patch (revert of complex mm_cid
management) from Thomas. He then builds his new implementation on top
to reduce overhead, but in a different way.

Thanks,

Mathieu

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