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From: Peter Zijlstra <peterz@infradead.org>
To: Frederic Weisbecker <frederic@kernel.org>
Cc: Huacai Chen <chenhuacai@kernel.org>,
	WANG Xuerui <kernel@xen0n.name>,
	Thomas Gleixner <tglx@linutronix.de>,
	"Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
	Anna-Maria Behnsen <anna-maria@linutronix.de>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: Loongson (and other $ARCHs?) idle VS timer enqueue
Date: Sat, 22 Apr 2023 10:08:14 +0200	[thread overview]
Message-ID: <20230422080814.GA1214746@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <ZEK+IeTYsauHLozy@lothringen>

On Fri, Apr 21, 2023 at 06:47:29PM +0200, Frederic Weisbecker wrote:

> > *HOWEVER*
> > 
> > intel_idle_irq() is affected -- except that we only (normally) use that
> > for very shallow idle states and it won't interact with NOHZ (because we
> > only disable the tick for deep idle states).
> 
> Well I don't know, that doesn't look comfortable... :)
> 
> Also why does it need to enable IRQs if ecx=1 ?

Supposedly this is some interrupt latency hack. See commit:

  c227233ad64c ("intel_idle: enable interrupts before C1 on Xeons")


  reply	other threads:[~2023-04-22  8:08 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-04-21 12:36 Frederic Weisbecker
2023-04-21 14:24 ` Peter Zijlstra
2023-04-21 16:47   ` Frederic Weisbecker
2023-04-22  8:08     ` Peter Zijlstra [this message]
2023-04-22 11:38       ` Peter Zijlstra
2023-04-22 14:48         ` Frederic Weisbecker
2023-04-21 15:24 ` Thomas Gleixner
2023-04-21 16:55   ` Frederic Weisbecker
2023-04-21 20:28     ` Thomas Gleixner
2023-04-22  8:17   ` Peter Zijlstra
2023-04-22  8:22     ` Peter Zijlstra
2023-04-22 14:21     ` Frederic Weisbecker
2023-04-22 15:04       ` Peter Zijlstra
2023-04-23 13:52         ` bibo, mao
2023-04-24  8:26           ` Frederic Weisbecker
2023-04-24 11:23             ` maobibo
2023-04-25 11:49           ` Peter Zijlstra
2023-04-25 13:25             ` maobibo
2023-04-25 13:28               ` WANG Xuerui
2023-04-26  0:46                 ` maobibo
2023-04-26  2:10                   ` WANG Xuerui
2023-04-26  2:23                     ` maobibo
2023-06-06 22:07             ` Frederic Weisbecker

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