From mboxrd@z Thu Jan 1 00:00:00 1970 From: Viresh Kumar Subject: Re: [PATCH v2] cpufreq: schedutil: Trace frequency only if it has changed Date: Thu, 23 Mar 2017 10:02:13 +0530 Message-ID: <20170323043213.GC12094@vireshk-i7> References: <10655562.4O9KtquB0A@aspire.rjw.lan> <2563394.lUgF3b60iC@aspire.rjw.lan> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mail-pf0-f179.google.com ([209.85.192.179]:32875 "EHLO mail-pf0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751271AbdCWEcS (ORCPT ); Thu, 23 Mar 2017 00:32:18 -0400 Received: by mail-pf0-f179.google.com with SMTP id o190so18378545pfo.0 for ; Wed, 22 Mar 2017 21:32:17 -0700 (PDT) Content-Disposition: inline In-Reply-To: <2563394.lUgF3b60iC@aspire.rjw.lan> Sender: linux-pm-owner@vger.kernel.org List-Id: linux-pm@vger.kernel.org To: "Rafael J. Wysocki" Cc: Linux PM , Peter Zijlstra , LKML , Patrick Bellasi , Vincent Guittot On 22-03-17, 18:32, Rafael J. Wysocki wrote: > From: Rafael J. Wysocki > > sugov_update_commit() calls trace_cpu_frequency() to record the > current CPU frequency if it has not changed in the fast switch case > to prevent utilities from getting confused (they may report that the > CPU is idle if the frequency has not been recorded for too long, for > example). > > However, that may cause the tracepoint to be triggered quite often > for no real reason (if the frequency doesn't change, we will not > modify the last update time stamp and governor computations may > run again shortly when that happens), so don't do that (arguably, it > is done to work around a utilities bug anyway). > > That allows code duplication in sugov_update_commit() to be reduced > somewhat too. > > Signed-off-by: Rafael J. Wysocki > --- > > -> v2: > Drop the trace_cpu_frequency() call in the sg_policy->next_freq == next_freq case. > > --- > kernel/sched/cpufreq_schedutil.c | 16 +++++++--------- > 1 file changed, 7 insertions(+), 9 deletions(-) Acked-by: Viresh Kumar -- viresh