From: Andrea Righi <arighi@nvidia.com>
To: Joel Fernandes <joelagnelf@nvidia.com>
Cc: Qais Yousef <qyousef@layalina.io>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Vincent Guittot <vincent.guittot@linaro.org>,
Juri Lelli <juri.lelli@redhat.com>,
Steven Rostedt <rostedt@goodmis.org>,
John Stultz <jstultz@google.com>,
Saravana Kannan <saravanak@google.com>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Frederic Weisbecker <frederic@kernel.org>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] Kconfig.hz: Change default HZ to 1000
Date: Sun, 23 Feb 2025 08:50:15 +0100 [thread overview]
Message-ID: <Z7rTNxHcXWizV3lq@gpd3> (raw)
In-Reply-To: <20250212145054.GA1965539@joelnvbox>
On Wed, Feb 12, 2025 at 09:50:54AM -0500, Joel Fernandes wrote:
> On Mon, Feb 10, 2025 at 12:19:15AM +0000, Qais Yousef wrote:
...
> > I believe HZ_250 was the default as a trade-off for battery power
> > devices that might not be happy with frequent TICKS potentially draining
> > the battery unnecessarily. But to my understanding the current state of
>
> Actually, on x86, me and Steve did some debug on Chromebooks and we found
> that HZ_250 actually increased power versus higher HZ. This was because
> cpuidle governor changes C states on the tick, and by making it less
> frequent, the CPU could be in a shallow C state for longer.
FWIW, I found the same about power consumption when we decided to switch to
CONFIG_HZ=1000 in the Ubuntu kernel:
https://discourse.ubuntu.com/t/enable-low-latency-features-in-the-generic-ubuntu-kernel-for-24-04/42255
-Andrea
next prev parent reply other threads:[~2025-02-23 7:50 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-02-10 0:19 [PATCH] Kconfig.hz: Change default HZ to 1000 Qais Yousef
2025-02-12 14:50 ` Joel Fernandes
2025-02-16 16:11 ` Qais Yousef
2025-02-23 7:50 ` Andrea Righi [this message]
2025-02-23 10:00 ` Ingo Molnar
2025-02-23 23:21 ` Qais Yousef
2025-02-24 13:16 ` Vincent Guittot
2025-02-24 23:23 ` Sean Christopherson
2025-02-13 8:24 ` Saravana Kannan
2025-02-16 16:29 ` Qais Yousef
2025-02-16 19:05 ` David Laight
2025-02-22 23:47 ` Qais Yousef
2025-02-28 10:33 ` Attila Fazekas
2025-03-02 12:05 ` David Laight
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