From: Andrew Morton <akpm@linux-foundation.org>
To: David Rientjes <rientjes@google.com>
Cc: "David Hildenbrand (Arm)" <david@kernel.org>,
Christoph Lameter <cl@gentwo.org>,
Vlastimil Babka <vbabka@kernel.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Sarthak Sharma <sarthak.sharma@arm.com>
Subject: Re: [patch v4] mm: vmstat_kunit: add synthetic benchmark for vm stats
Date: Sat, 26 Sep 2026 15:38:07 -0700 [thread overview]
Message-ID: <20260926153807.ec8a4ea8cb362e4f583cc9b4@linux-foundation.org> (raw)
In-Reply-To: <cfc1edae-8aaa-8fd0-95de-af3d4774c6dd@google.com>
On Fri, 18 Sep 2026 13:39:52 -0700 (PDT) David Rientjes <rientjes@google.com> wrote:
> From: Christoph Lameter <cl@gentwo.org>
>
> Add a synthetic benchmark that can be used to measure performance of VM
> statistics. This is used to analyze any improvements or regressions in
> functions that are frequently used in hot code paths.
>
> The test is run by KUnit or doing modprobe vmstat_kunit directly.
>
> Sample output:
> KTAP version 1
> 1..1
> KTAP version 1
> # Subtest: vmstat
> # module: vmstat_kunit
> 1..3
> # vmstat_test_inc_dec_zone_page_state: 10000 ops: inc_zone_page_state -> 8 cycles (4 ns/op), dec_zone_page_state -> 9 cycles (4 ns/op)
> ok 1 vmstat_test_inc_dec_zone_page_state
> # vmstat_test_interleaved_zone_page_state: 10000 ops: inc/dec pair -> 17 cycles (8 ns/op)
> ok 2 vmstat_test_interleaved_zone_page_state
> # vmstat_test_count_vm_event: 10000 ops: count_vm_event -> 4 cycles (2 ns/op)
> ok 3 vmstat_test_count_vm_event
> # vmstat: pass:3 fail:0 skip:0 total:3
> # Totals: pass:3 fail:0 skip:0 total:3
> ok 1 vmstat
This hasn't generated a lot of interest.
Can you better explain the value? How do you anticipate that people
use this? What value does it offer? Sell it to us!
People could use it across kernel versions to detect performance
regressions/improvements. "kernel test robot" appears to already be
set up to track this (eg,
https://lore.kernel.org/202609230824.7a9189aa-lkp@intel.com). Do you
anticipate that this module will be wired into such projects?
Other than that, it seems it's mainly a developer-centric thing? An
individual developer could use it to verify that a proposed vmstat
change doesn't slow things down, or that it does speed things up, if
that was the intent.
Will google use this internally, or will they do so? If so, how?
prev parent reply other threads:[~2026-09-26 22:38 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-18 20:39 David Rientjes
2026-09-26 21:48 ` David Rientjes
2026-09-26 22:38 ` Andrew Morton [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20260926153807.ec8a4ea8cb362e4f583cc9b4@linux-foundation.org \
--to=akpm@linux-foundation.org \
--cc=cl@gentwo.org \
--cc=david@kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mathieu.desnoyers@efficios.com \
--cc=rientjes@google.com \
--cc=sarthak.sharma@arm.com \
--cc=vbabka@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
all inboxes | Powered by JetHome®