From: Peter Zijlstra <peterz@infradead.org>
To: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Steven Rostedt <rostedt@goodmis.org>,
Joel Fernandes <joel@joelfernandes.org>,
Prakash Sangappa <prakash.sangappa@oracle.com>,
linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org,
Thomas Gleixner <tglx@linutronix.de>,
Ankur Arora <ankur.a.arora@oracle.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
linux-mm@kvack.org, x86@kernel.org,
Andrew Morton <akpm@linux-foundation.org>,
luto@kernel.org, bp@alien8.de, dave.hansen@linux.intel.com,
hpa@zytor.com, juri.lelli@redhat.com, vincent.guittot@linaro.org,
willy@infradead.org, mgorman@suse.de, jon.grimm@amd.com,
bharata@amd.com, raghavendra.kt@amd.com,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Konrad Wilk <konrad.wilk@oracle.com>,
jgross@suse.com, Andrew.Cooper3@citrix.com,
Vineeth Pillai <vineethrp@google.com>,
Suleiman Souhlal <suleiman@google.com>,
Ingo Molnar <mingo@kernel.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Clark Williams <clark.williams@gmail.com>,
daniel.wagner@suse.com,
Joseph Salisbury <joseph.salisbury@oracle.com>,
broonie@gmail.com
Subject: Re: [RFC][PATCH 1/2] sched: Extended scheduler time slice
Date: Thu, 6 Feb 2025 15:27:17 +0100 [thread overview]
Message-ID: <20250206142717.GS7145@noisy.programming.kicks-ass.net> (raw)
In-Reply-To: <20250206142234.-kcSg0xr@linutronix.de>
On Thu, Feb 06, 2025 at 03:22:34PM +0100, Sebastian Andrzej Siewior wrote:
> Then this feature adds 20us on top?
The point has always been for the number to be < the observable
scheduling latency.
I'm not sure what that number is, and it is always hardware dependent. I
measured it on a random test box when I did the prototype a long while
ago, and ended up at 50us, but for all I know that machine was running a
lockdep enabled kernel at the time (won't be the first and certainly
won't be the last time I try and do a performance measurement on a debug
kernel).
That was not the important part -- but everybody fixates on the number,
instead of the intent.
I'm assuming you have a recent number around -- what's sane? 5us, less?
next prev parent reply other threads:[~2025-02-06 14:27 UTC|newest]
Thread overview: 66+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-01-31 22:58 [RFC][PATCH 0/2] sched: Extended Scheduler Time Slice revisited Steven Rostedt
2025-01-31 22:58 ` [RFC][PATCH 1/2] sched: Extended scheduler time slice Steven Rostedt
2025-02-01 11:59 ` Peter Zijlstra
2025-02-01 12:47 ` Steven Rostedt
2025-02-01 18:11 ` Peter Zijlstra
2025-02-01 23:06 ` Steven Rostedt
2025-02-03 8:43 ` Peter Zijlstra
2025-02-03 8:53 ` Peter Zijlstra
2025-02-03 16:45 ` Steven Rostedt
2025-02-04 3:28 ` Suleiman Souhlal
2025-02-04 3:57 ` Steven Rostedt
2025-02-04 9:16 ` Peter Zijlstra
2025-02-04 12:51 ` Steven Rostedt
2025-02-04 13:16 ` Steven Rostedt
2025-02-04 15:05 ` Steven Rostedt
2025-02-04 15:30 ` Peter Zijlstra
2025-02-04 16:11 ` Steven Rostedt
2025-02-05 9:07 ` Peter Zijlstra
2025-02-05 13:10 ` Steven Rostedt
2025-02-05 13:44 ` Steven Rostedt
2025-02-04 22:44 ` Prakash Sangappa
2025-02-05 0:56 ` Joel Fernandes
2025-02-05 3:04 ` Steven Rostedt
2025-02-05 5:09 ` Joel Fernandes
2025-02-05 13:16 ` Steven Rostedt
2025-02-05 13:38 ` Steven Rostedt
2025-02-05 21:08 ` Prakash Sangappa
2025-02-05 21:19 ` Steven Rostedt
2025-02-05 21:33 ` Steven Rostedt
2025-02-05 21:36 ` Prakash Sangappa
2025-02-06 3:07 ` Joel Fernandes
2025-02-06 13:30 ` Steven Rostedt
2025-02-06 13:44 ` Sebastian Andrzej Siewior
2025-02-06 13:48 ` Peter Zijlstra
2025-02-06 13:53 ` Sebastian Andrzej Siewior
2025-02-06 13:57 ` Peter Zijlstra
2025-02-06 14:20 ` Steven Rostedt
2025-02-06 14:22 ` Sebastian Andrzej Siewior
2025-02-06 14:27 ` Peter Zijlstra [this message]
2025-02-06 14:57 ` Steven Rostedt
2025-02-06 15:01 ` Sebastian Andrzej Siewior
2025-02-10 19:43 ` Steven Rostedt
2025-02-10 22:04 ` David Laight
2025-02-10 22:15 ` Steven Rostedt
2025-02-11 8:21 ` Sebastian Andrzej Siewior
2025-02-11 10:57 ` Peter Zijlstra
2025-02-11 15:28 ` Steven Rostedt
2025-02-12 12:11 ` Sebastian Andrzej Siewior
2025-02-12 15:00 ` Steven Rostedt
2025-02-12 15:18 ` Sebastian Andrzej Siewior
2025-02-10 14:07 ` Joel Fernandes
2025-02-10 19:48 ` Steven Rostedt
2025-02-10 17:20 ` David Laight
2025-02-10 17:27 ` Steven Rostedt
2025-02-10 19:44 ` Steven Rostedt
2025-02-10 21:51 ` David Laight
2025-02-10 21:58 ` Steven Rostedt
2025-02-01 14:35 ` Mathieu Desnoyers
2025-02-01 23:08 ` Steven Rostedt
2025-02-01 23:18 ` Linus Torvalds
2025-02-01 23:35 ` Linus Torvalds
2025-02-02 3:26 ` Steven Rostedt
2025-02-02 3:22 ` Steven Rostedt
2025-02-02 7:22 ` Matthew Wilcox
2025-02-02 22:29 ` Steven Rostedt
2025-01-31 22:58 ` [RFC][PATCH 2/2] sched: Shorten time that tasks can extend their time slice for Steven Rostedt
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