From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Dirk Brandewie , "Rafael J. Wysocki" Subject: [ 085/102] cpufreq / intel_pstate: fix ffmpeg regression Date: Fri, 17 May 2013 14:36:40 -0700 Message-Id: <20130517213253.223861866@linuxfoundation.org> In-Reply-To: <20130517213244.277411019@linuxfoundation.org> References: <20130517213244.277411019@linuxfoundation.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Dirk Brandewie commit ca182aee389f8026401510f4c63841cb02c820e8 upstream. The ffmpeg benchmark in the phoronix test suite has threads on multiple cores that rely on the progress on of threads on other cores and ping pong back and forth fast enough to make the core appear less busy than it "should" be. If the core has been at minimum p-state for a while bump the pstate up to kick the core to see if it is in this ping pong state. If the core is truly idle the p-state will be reduced at the next sample time. If the core makes more progress it will send more work to the thread bringing both threads out of the ping pong scenario and the p-state will be selected normally. This fixes a performance regression of approximately 30% Signed-off-by: Dirk Brandewie Signed-off-by: Rafael J. Wysocki Signed-off-by: Greg Kroah-Hartman --- drivers/cpufreq/intel_pstate.c | 10 ++-------- 1 file changed, 2 insertions(+), 8 deletions(-) --- a/drivers/cpufreq/intel_pstate.c +++ b/drivers/cpufreq/intel_pstate.c @@ -551,22 +551,16 @@ static void intel_pstate_timer_func(unsi struct cpudata *cpu = (struct cpudata *) __data; intel_pstate_sample(cpu); + intel_pstate_adjust_busy_pstate(cpu); - if (!cpu->idle_mode) - intel_pstate_adjust_busy_pstate(cpu); - else - intel_pstate_adjust_idle_pstate(cpu); - -#if defined(XPERF_FIX) if (cpu->pstate.current_pstate == cpu->pstate.min_pstate) { cpu->min_pstate_count++; if (!(cpu->min_pstate_count % 5)) { intel_pstate_set_pstate(cpu, cpu->pstate.max_pstate); - intel_pstate_idle_mode(cpu); } } else cpu->min_pstate_count = 0; -#endif + intel_pstate_set_sample_time(cpu); }