linux-kernel - Re: [PATCH v3 0/2] pipe: don't update {a,c,m}time for anonymous pipes

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Message-ID: <28ed3e72-d219-4a02-aa8a-5b3ab413bc65@amd.com>
Date: Thu, 6 Feb 2025 08:42:12 +0530
From: K Prateek Nayak <kprateek.nayak@....com>
To: Oleg Nesterov <oleg@...hat.com>
CC: David Howells <dhowells@...hat.com>, "Gautham R. Shenoy"
	<gautham.shenoy@....com>, Mateusz Guzik <mjguzik@...il.com>, Neeraj Upadhyay
	<Neeraj.Upadhyay@....com>, Christian Brauner <brauner@...nel.org>, "Jeff
 Layton" <jlayton@...nel.org>, Oliver Sang <oliver.sang@...el.com>, "Swapnil
 Sapkal" <swapnil.sapkal@....com>, WangYuli <wangyuli@...ontech.com>,
	<linux-fsdevel@...r.kernel.org>, <linux-kernel@...r.kernel.org>, "Linus
 Torvalds" <torvalds@...ux-foundation.org>
Subject: Re: [PATCH v3 0/2] pipe: don't update {a,c,m}time for anonymous pipes

Hello Oleg,

On 2/5/2025 11:47 PM, Oleg Nesterov wrote:
> OK, let me send v3 right now...

Tested this series with sched-messaging on my 3rd Generation EPYC
system (2 x64c/128T, boost on, C2 disabled) and I see slight
improvements:

   ==================================================================
   Test          : sched-messaging
   Units         : Normalized time in seconds
   Interpretation: Lower is better
   Statistic     : AMean
   ==================================================================
   Case:      upstream[pct imp](CV)    skip_{a,c,m}_time[pct imp](CV)
    1-groups     1.00 [ -0.00]( 9.88)     1.05 [ -5.16]( 7.19) *
    2-groups     1.00 [ -0.00]( 3.49)     0.97 [  2.70]( 3.54)
    4-groups     1.00 [ -0.00]( 1.22)     0.97 [  2.70]( 2.78)
    8-groups     1.00 [ -0.00]( 0.80)     0.99 [  0.94]( 1.04)
   16-groups     1.00 [ -0.00]( 1.40)     0.98 [  2.43]( 1.02)
   
   * Disregard these data points due to large run to run variation

Feel free to add:

Tested-by: K Prateek Nayak <kprateek.nayak@....com>

I'll go test the pipe_{read,write}() cleanup you had posted on the
other thread.

-- 
Thanks and Regards,
Prateek

> 
> Changes: make pipeanon_fops static.
> 
> Link to v1: https://lore.kernel.org/all/20250204132153.GA20921@redhat.com/
> Link to v2: https://lore.kernel.org/all/20250205161636.GA1001@redhat.com/
> 
> Oleg.
> ---
> 
>   fs/pipe.c | 62 +++++++++++++++++++++++++++++++++++++++++++++++---------------
>   1 file changed, 47 insertions(+), 15 deletions(-)
>