From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752728AbbIPPPT (ORCPT ); Wed, 16 Sep 2015 11:15:19 -0400 Received: from mx0b-0016f401.pphosted.com ([67.231.156.173]:50290 "EHLO mx0b-0016f401.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751934AbbIPPPR (ORCPT ); Wed, 16 Sep 2015 11:15:17 -0400 Date: Wed, 16 Sep 2015 23:11:05 +0800 From: Jisheng Zhang To: Lorenzo Pieralisi , Catalin Marinas , Will Deacon CC: "linux-kernel@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" Subject: Re: [PATCH] arm64: add cpu_idle tracepoints to arch_cpu_idle Message-ID: <20150916231105.11a0e65e@xhacker> In-Reply-To: <20150916225312.0d4d32c5@xhacker> References: <1442413401-2955-1-git-send-email-jszhang@marvell.com> <20150916144738.GA23245@red-moon> <20150916225312.0d4d32c5@xhacker> X-Mailer: Claws Mail 3.12.0 (GTK+ 2.24.28; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2015-09-16_03:,, signatures=0 X-Proofpoint-Spam-Details: rule=inbound_notspam policy=inbound score=0 spamscore=0 suspectscore=2 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1507310000 definitions=main-1509160195 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Dear Lorenzo, On Wed, 16 Sep 2015 22:53:12 +0800 Jisheng Zhang wrote: > Dear Lorenzo, > > On Wed, 16 Sep 2015 15:47:38 +0100 > Lorenzo Pieralisi wrote: > > > On Wed, Sep 16, 2015 at 03:23:21PM +0100, Jisheng Zhang wrote: > > > Currently, if cpuidle is disabled or not supported, powertop reports > > > zero wakeups and zero events. This is due to the cpu_idle tracepoints > > > are missing. > > > > > > This patch is to make cpu_idle tracepoints always available even if > > > cpuidle is disabled or not supported. > > > > > > Signed-off-by: Jisheng Zhang > > > > Is there a reason why this code cannot be moved to the generic idle loop ? > > Do you mean the cpu_idle_loop() in kernel/sched/idle.c? To be honest, I Maybe I know now. we need to trace different idle level, for example: WFI idle: trace_cpu_idle_rcuidle(1, ...); deeper idle: trace_cpu_idle_rcuidle(2, ...); Usually, the first argument of trace_cpu_idle_rcuidle() equals to the index of the idle level. so generic idle loop is not a good candidate. > dunno. Maybe kernel experts can give some hints. > > Thanks, > Jisheng > > > > > Thanks, > > Lorenzo > > > > > --- > > > arch/arm64/kernel/process.c | 3 +++ > > > 1 file changed, 3 insertions(+) > > > > > > diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c > > > index 223b093..f75b540 100644 > > > --- a/arch/arm64/kernel/process.c > > > +++ b/arch/arm64/kernel/process.c > > > @@ -44,6 +44,7 @@ > > > #include > > > #include > > > #include > > > +#include > > > > > > #include > > > #include > > > @@ -75,8 +76,10 @@ void arch_cpu_idle(void) > > > * This should do all the clock switching and wait for interrupt > > > * tricks > > > */ > > > + trace_cpu_idle_rcuidle(1, smp_processor_id()); > > > cpu_do_idle(); > > > local_irq_enable(); > > > + trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, smp_processor_id()); > > > } > > > > > > #ifdef CONFIG_HOTPLUG_CPU > > > -- > > > 2.5.1 > > > > > > -- > > > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > > > the body of a message to majordomo@vger.kernel.org > > > More majordomo info at http://vger.kernel.org/majordomo-info.html > > > Please read the FAQ at http://www.tux.org/lkml/ > > > > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel