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 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 9CD0CC43381 for ; Tue, 19 Feb 2019 10:26:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 582912177E for ; Tue, 19 Feb 2019 10:26:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728235AbfBSK0C (ORCPT ); Tue, 19 Feb 2019 05:26:02 -0500 Received: from cloudserver094114.home.pl ([79.96.170.134]:58333 "EHLO cloudserver094114.home.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727023AbfBSK0C (ORCPT ); Tue, 19 Feb 2019 05:26:02 -0500 Received: from 79.184.254.15.ipv4.supernova.orange.pl (79.184.254.15) (HELO aspire.rjw.lan) by serwer1319399.home.pl (79.96.170.134) with SMTP (IdeaSmtpServer 0.83.183) id afe34b449a1f16d5; Tue, 19 Feb 2019 11:26:00 +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 v3] PM / suspend: measure the time of filesystem syncing Date: Tue, 19 Feb 2019 11:24:36 +0100 Message-ID: <2819109.DzhZvocLkm@aspire.rjw.lan> In-Reply-To: <20190214111543.22137-1-harry.pan@intel.com> References: <20190206154214.576-1-harry.pan@intel.com> <20190214111543.22137-1-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 Thursday, February 14, 2019 12:15:43 PM 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. > > v2: simplify the variables, apply the simplest form of ktime API. > v3: reduce conditional compilation, rectify profiling in better syntax > > Signed-off-by: Harry Pan > --- > kernel/power/suspend.c | 21 ++++++++++++++------- > 1 file changed, 14 insertions(+), 7 deletions(-) > > diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c > index 0bd595a0b610..4844fc6a796d 100644 > --- a/kernel/power/suspend.c > +++ b/kernel/power/suspend.c > @@ -568,13 +568,20 @@ static int enter_state(suspend_state_t state) > if (state == PM_SUSPEND_TO_IDLE) > s2idle_begin(); > > -#ifndef CONFIG_SUSPEND_SKIP_SYNC > - trace_suspend_resume(TPS("sync_filesystems"), 0, true); > - pr_info("Syncing filesystems ... "); > - ksys_sync(); > - pr_cont("done.\n"); > - trace_suspend_resume(TPS("sync_filesystems"), 0, false); > -#endif > + if (!IS_ENABLED(CONFIG_SUSPEND_SKIP_SYNC)) { > + ktime_t start; > + unsigned int elapsed_msecs; > + > + trace_suspend_resume(TPS("sync_filesystems"), 0, true); > + pr_info("Syncing filesystems ... "); > + start = ktime_get(); > + ksys_sync(); > + elapsed_msecs = ktime_to_ms(ktime_sub(ktime_get(), start)); > + pr_cont("(elapsed %d.%03d seconds) done.\n", > + elapsed_msecs / MSEC_PER_SEC, > + elapsed_msecs % MSEC_PER_SEC); One more nit. Since you are printing the sync time anyway, there is a little sense to split the message using pr_cont() that may be messed up with by any intervening messages, so why don't you just print a one-line pr_info("Filesystems sync: %d.%03d seconds\n", ...) message? Also, if you change it here, I guess it would be consistent to make an analogous change for hibernation. > + trace_suspend_resume(TPS("sync_filesystems"), 0, false); > + } > > pm_pr_dbg("Preparing system for sleep (%s)\n", mem_sleep_labels[state]); > pm_suspend_clear_flags(); >