From: Dmitry Ilvokhin <d@ilvokhin.com>
To: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>
Cc: linux-kernel@vger.kernel.org, kernel-team@meta.com
Subject: Re: [PATCH v2] x86/irq: Optimize interrupts decimals printing
Date: Wed, 25 Feb 2026 17:22:06 +0000 [thread overview]
Message-ID: <aZ8vvlwRbkzzpHqo@shell.ilvokhin.com> (raw)
In-Reply-To: <aQj5mGZ6_BBlAm3B@shell.ilvokhin.com>
I would like to follow up on this patch with additional data from production
deployment.
We have rolled out this change to a subset of the Meta fleet. On each machine,
dynolog [1] periodically reads /proc/interrupts to collect per-CPU interrupt
statistics, so this path executes frequently across the fleet.
After deploying the patch, we measured the reduction in CPU cycles
spent in the /proc/interrupts read path on machines with different
virtual core counts.
vCores Cycle reduction
------ ---------------
36 -18.9%
72 -25.5%
252 -34.7%
As expected, the benefit increases with higher core counts, since the
formatting work scales with the number of CPUs.
We have not observed any functional regressions or changes in the output
format. Existing userspace parsers continue to work without
modification.
Please let me know if there are any concerns or if additional data would be
helpful.
[1]: https://github.com/facebookincubator/dynolog
next prev parent reply other threads:[~2026-02-25 17:22 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-11-03 18:51 [PATCH v2] x86/irq: Optimize interrupts decimals printing Dmitry Ilvokhin
2026-02-25 17:22 ` Dmitry Ilvokhin [this message]
2026-02-27 13:20 ` Thomas Gleixner
2026-02-27 14:04 ` Dmitry Ilvokhin
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