From: Peter Zijlstra <peterz@infradead.org>
To: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Hogan <james.hogan@imgtec.com>,
"mingo@kernel.org" <mingo@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
"luto@amacapital.net" <luto@amacapital.net>,
"nicolas.pitre@linaro.org" <nicolas.pitre@linaro.org>,
"daniel.lezcano@linaro.org" <daniel.lezcano@linaro.org>,
"umgwanakikbuti@gmail.com" <umgwanakikbuti@gmail.com>,
LKML <linux-kernel@vger.kernel.org>,
Will Deacon <Will.Deacon@arm.com>,
ARM Kernel List <linux-arm-kernel@lists.infradead.org>
Subject: Re: [RFC][PATCH 6/8] sched,idle: Avoid spurious wakeup IPIs
Date: Fri, 9 May 2014 19:02:34 +0200 [thread overview]
Message-ID: <20140509170234.GZ30445@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <20140509145745.GI7950@arm.com>
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On Fri, May 09, 2014 at 03:57:45PM +0100, Catalin Marinas wrote:
> On Fri, May 09, 2014 at 03:50:02PM +0100, Peter Zijlstra wrote:
> > On Fri, May 09, 2014 at 03:40:34PM +0100, Catalin Marinas wrote:
> >
> > > I wonder why we still need TIF_POLLING_NRFLAG for arm64. It was on arm
> > > until commit 16a8016372c42c7628eb (sanitize tsk_is_polling()). On arm64
> > > we use wfi for idle or a firmware call but in both cases the assumption
> > > is that we need an interrupt for waking up.
> > >
> > > So I think we should remove this macro for arm64.
> >
> > Does ARM64 support idle=poll? If so, you could keep it for that,
> > otherwise it does indeed appear to be pointless.
>
> We don't support idle=poll either.
>
> > As to 32bit ARM, are there SMP chips which do not have WFI?
>
> No. WFI is even used for the secondary booting protocol (we need to send
> an IPI to get them going).
OK, so I'll queue a patch removing TIF_POLLING_NRFLAG for arm64.
Thanks!
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next prev parent reply other threads:[~2014-05-09 17:02 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-04-11 13:42 [RFC][PATCH 0/8] sched,idle: need resched polling rework Peter Zijlstra
2014-04-11 13:42 ` [RFC][PATCH 1/8] sched,idle,alpha: Switch from TS_POLLING to TIF_POLLING_NRFLAG Peter Zijlstra
2014-04-11 14:38 ` Richard Henderson
2014-04-11 13:42 ` [RFC][PATCH 2/8] sched,idle,tile: " Peter Zijlstra
2014-04-11 15:15 ` Chris Metcalf
2014-04-11 15:30 ` Peter Zijlstra
2014-04-11 13:42 ` [RFC][PATCH 3/8] sched,idle,ia64: " Peter Zijlstra
2014-04-11 13:42 ` [RFC][PATCH 4/8] sched,idle,x86: " Peter Zijlstra
2014-04-11 13:42 ` [RFC][PATCH 5/8] sched,idle: Remove TS_POLLING support Peter Zijlstra
2014-04-11 13:42 ` [RFC][PATCH 6/8] sched,idle: Avoid spurious wakeup IPIs Peter Zijlstra
2014-04-13 21:41 ` Nicolas Pitre
2014-05-09 13:37 ` James Hogan
2014-05-09 14:15 ` Peter Zijlstra
2014-05-09 14:40 ` Catalin Marinas
2014-05-09 14:50 ` Peter Zijlstra
2014-05-09 14:57 ` Catalin Marinas
2014-05-09 17:02 ` Peter Zijlstra [this message]
2014-05-09 17:06 ` Peter Zijlstra
2014-05-09 17:09 ` Catalin Marinas
2014-05-09 17:20 ` Peter Zijlstra
2014-05-19 12:54 ` [tip:sched/arch] arm64: Remove TIF_POLLING_NRFLAG tip-bot for Peter Zijlstra
2014-05-22 12:26 ` [tip:sched/core] " tip-bot for Peter Zijlstra
2014-05-09 14:51 ` [RFC][PATCH 6/8] sched,idle: Avoid spurious wakeup IPIs James Hogan
2014-05-15 9:17 ` James Hogan
2014-05-19 12:54 ` [tip:sched/arch] metag: Remove TIF_POLLING_NRFLAG tip-bot for James Hogan
2014-05-22 12:26 ` [tip:sched/core] " tip-bot for James Hogan
2014-04-11 13:42 ` [RFC][PATCH 7/8] sched,idle: Delay clearing the polling bit Peter Zijlstra
2014-04-13 21:51 ` Nicolas Pitre
2014-04-11 13:42 ` [RFC][PATCH 8/8] sched,idle: Reflow cpuidle_idle_call() Peter Zijlstra
2014-04-13 21:36 ` Nicolas Pitre
2014-04-14 8:59 ` Peter Zijlstra
2014-04-14 9:25 ` Peter Zijlstra
2014-04-14 13:55 ` Nicolas Pitre
2014-04-11 15:00 ` [RFC][PATCH 0/8] sched,idle: need resched polling rework Andy Lutomirski
2014-04-11 15:14 ` Peter Zijlstra
2014-05-22 12:58 ` Peter Zijlstra
2014-05-22 13:09 ` Peter Zijlstra
2014-05-29 0:01 ` Andy Lutomirski
2014-05-29 6:48 ` Peter Zijlstra
2014-06-03 6:40 ` Andy Lutomirski
2014-06-03 6:51 ` Peter Zijlstra
2014-06-03 10:43 ` Peter Zijlstra
2014-06-03 14:02 ` Peter Zijlstra
2014-06-03 16:05 ` Andy Lutomirski
2014-06-03 16:19 ` Peter Zijlstra
2014-06-03 16:52 ` Andy Lutomirski
2014-06-03 17:00 ` Peter Zijlstra
2014-06-03 18:28 ` Peter Zijlstra
2014-06-03 18:44 ` Andy Lutomirski
2014-06-03 20:07 ` Andy Lutomirski
2014-04-12 8:35 ` Mike Galbraith
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