From: Peter Zijlstra <peterz@infradead.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: LKML <linux-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, akpm@linux-foundation.org,
luto@kernel.org, bp@alien8.de, dave.hansen@linux.intel.com,
hpa@zytor.com, mingo@redhat.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@oracle.com, konrad.wilk@oracle.com,
jgross@suse.com, andrew.cooper3@citrix.com,
Joel Fernandes <joel@joelfernandes.org>,
Youssef Esmat <youssefesmat@chromium.org>,
Vineeth Pillai <vineethrp@google.com>,
Suleiman Souhlal <suleiman@google.com>,
Ingo Molnar <mingo@kernel.org>,
Daniel Bristot de Oliveira <bristot@kernel.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Subject: Re: [POC][RFC][PATCH v2] sched: Extended Scheduler Time Slice
Date: Thu, 26 Oct 2023 12:59:44 +0200 [thread overview]
Message-ID: <20231026105944.GJ33965@noisy.programming.kicks-ass.net> (raw)
In-Reply-To: <20231025235413.597287e1@gandalf.local.home>
On Wed, Oct 25, 2023 at 11:54:13PM -0400, Steven Rostedt wrote:
> static void extend(void)
> {
> rseq_map.cr_flags = 1;
> }
>
> static void unextend(void)
> {
> unsigned long prev;
>
> prev = xchg(&rseq_map.cr_flags, 0);
So you complain about overhead and then you add one of the most
expensive ops possible here? xchg has an implicit LOCK prefix and you
really don't need LOCK prefix here.
> if (prev & 2) {
> tracefs_printf(NULL, "Yield!\n");
> sched_yield();
> }
> }
next prev parent reply other threads:[~2023-10-26 11:00 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-26 3:54 [POC][RFC][PATCH v2] sched: Extended Scheduler Time Slice Steven Rostedt
2023-10-26 10:59 ` Peter Zijlstra [this message]
2023-10-26 11:14 ` Steven Rostedt
2023-10-26 18:36 ` Mathieu Desnoyers
2023-10-26 18:50 ` Linus Torvalds
2023-10-26 18:59 ` Mathieu Desnoyers
2023-10-26 19:36 ` Steven Rostedt
2023-10-26 20:45 ` Steven Rostedt
[not found] ` <644da047-2f7a-4d55-a339-f2dc28d2c852@efficios.com>
[not found] ` <20231027122442.5c76dd62@gandalf.local.home>
2023-10-27 16:35 ` Mathieu Desnoyers
2023-10-27 16:49 ` Steven Rostedt
2023-10-30 12:56 ` Mathieu Desnoyers
2023-10-30 13:45 ` Steven Rostedt
2023-10-30 18:05 ` Mathieu Desnoyers
2023-10-30 18:19 ` Steven Rostedt
2023-10-30 18:27 ` Mathieu Desnoyers
2023-10-30 18:39 ` Steven Rostedt
2023-10-26 19:20 ` Steven Rostedt
2023-10-26 21:35 ` Steven Rostedt
2023-10-27 21:52 ` Steven Rostedt
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