From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2AC57C282CB for ; Tue, 5 Feb 2019 11:56:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E21342080F for ; Tue, 5 Feb 2019 11:56:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728542AbfBEL4Q (ORCPT ); Tue, 5 Feb 2019 06:56:16 -0500 Received: from cloudserver094114.home.pl ([79.96.170.134]:56404 "EHLO cloudserver094114.home.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725947AbfBEL4P (ORCPT ); Tue, 5 Feb 2019 06:56:15 -0500 Received: from 79.184.254.36.ipv4.supernova.orange.pl (79.184.254.36) (HELO aspire.rjw.lan) by serwer1319399.home.pl (79.96.170.134) with SMTP (IdeaSmtpServer 0.83.183) id 591d23d00c9b99f8; Tue, 5 Feb 2019 12:56:13 +0100 From: "Rafael J. Wysocki" To: Harry Pan Cc: LKML , gs0622@gmail.com, pavel@ucw.cz, len.brown@intel.com, linux-pm@vger.kernel.org Subject: Re: [PATCH] PM / suspend: measure the time of filesystem syncing Date: Tue, 05 Feb 2019 12:55:01 +0100 Message-ID: <1702604.tyfAVjpQ0o@aspire.rjw.lan> In-Reply-To: <20190203052007.27392-1-harry.pan@intel.com> References: <20190203052007.27392-1-harry.pan@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sunday, February 3, 2019 6:20:07 AM CET Harry Pan wrote: > This patch gives the reader an intuitive metric of the time cost by > the kernel issuing a filesystem sync during suspend; although developer > can guess by the timestamp of next log or enable the ftrace power event > for manual calculation, this manner is easier to read and benefits the > automatic script. > > Signed-off-by: Harry Pan > --- > kernel/power/suspend.c | 9 ++++++++- > 1 file changed, 8 insertions(+), 1 deletion(-) > > diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c > index 0bd595a0b610..f3b7c64f2242 100644 > --- a/kernel/power/suspend.c > +++ b/kernel/power/suspend.c > @@ -550,6 +550,8 @@ static void suspend_finish(void) > static int enter_state(suspend_state_t state) > { > int error; > + ktime_t start, end, elapsed; Why do you need three vars here? One should be sufficient. > + unsigned int elapsed_msecs; > > trace_suspend_resume(TPS("suspend_enter"), state, true); > if (state == PM_SUSPEND_TO_IDLE) { > @@ -570,9 +572,14 @@ static int enter_state(suspend_state_t state) > > #ifndef CONFIG_SUSPEND_SKIP_SYNC > trace_suspend_resume(TPS("sync_filesystems"), 0, true); > + start = ktime_get_boottime(); Why _boottime()? > pr_info("Syncing filesystems ... "); > ksys_sync(); > - pr_cont("done.\n"); > + end = ktime_get_boottime(); > + elapsed = ktime_sub(end, start); > + elapsed_msecs = ktime_to_ms(elapsed); > + pr_cont("(elapsed %d.%03d seconds) done.\n", elapsed_msecs / 1000, > + elapsed_msecs % 1000); > trace_suspend_resume(TPS("sync_filesystems"), 0, false); > #endif > >