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Date: Sun, 12 Apr 2015 20:02:35 -0700 From: Davidlohr Bueso <dave@...olabs.net> To: Sebastian Andrzej Siewior <bigeasy@...utronix.de> Cc: Thomas Gleixner <tglx@...utronix.de>, linux-kernel@...r.kernel.org, Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...hat.com>, Darren Hart <darren@...art.com>, Steven Rostedt <rostedt@...dmis.org>, fredrik.markstrom@...driver.com, Manfred Spraul <manfred@...orfullife.com> Subject: Re: [PATCH 2/3 v2] futex: avoid double wake up in futex_wake() on -RT On Fri, 2015-04-10 at 18:11 +0200, Sebastian Andrzej Siewior wrote: > This patch delays the wakeup of the process untill ^^^ until > the hb->lock is > dropped to avoid boosting + context switch to obtain the lock. Doing the wakeups while holding the lock is also a general performance issue for futex_wake. The problem being dealing with spurious wakeups (wacky drivers), which makes no difference wrt nr_wake. Thanks, Davidlohr -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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