Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757497Ab3EQVn5 (ORCPT ); Fri, 17 May 2013 17:43:57 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:54347 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757244Ab3EQVh5 (ORCPT ); Fri, 17 May 2013 17:37:57 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Mike Lothian , Dirk Brandewie , "Rafael J. Wysocki" Subject: [ 083/102] cpufreq / intel_pstate: remove idle time and duration from sample and calculations Date: Fri, 17 May 2013 14:36:38 -0700 Message-Id: <20130517213253.040195185@linuxfoundation.org> X-Mailer: git-send-email 1.8.3.rc0.20.gb99dd2e In-Reply-To: <20130517213244.277411019@linuxfoundation.org> References: <20130517213244.277411019@linuxfoundation.org> User-Agent: quilt/0.60-5.1.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3658 Lines: 112 3.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Dirk Brandewie commit 1abc4b20b85b42e8573957e54b193385cf48b0d6 upstream. Idle time is taken into account in the APERF/MPERF ratio calculation there is no reason for the driver to track it seperately. This reduces the work in the driver and makes the code more readable. Removal of the tracking of sample duration removes the possibility of the divide by zero exception when the duration is sub 1us References: https://bugzilla.kernel.org/show_bug.cgi?id=56691 Reported-by: Mike Lothian Signed-off-by: Dirk Brandewie Signed-off-by: Rafael J. Wysocki Signed-off-by: Greg Kroah-Hartman --- drivers/cpufreq/intel_pstate.c | 43 ++++++----------------------------------- 1 file changed, 7 insertions(+), 36 deletions(-) --- a/drivers/cpufreq/intel_pstate.c +++ b/drivers/cpufreq/intel_pstate.c @@ -48,12 +48,7 @@ static inline int32_t div_fp(int32_t x, } struct sample { - ktime_t start_time; - ktime_t end_time; int core_pct_busy; - int pstate_pct_busy; - u64 duration_us; - u64 idletime_us; u64 aperf; u64 mperf; int freq; @@ -91,8 +86,6 @@ struct cpudata { int min_pstate_count; int idle_mode; - ktime_t prev_sample; - u64 prev_idle_time_us; u64 prev_aperf; u64 prev_mperf; int sample_ptr; @@ -450,48 +443,26 @@ static inline void intel_pstate_calc_bus struct sample *sample) { u64 core_pct; - sample->pstate_pct_busy = 100 - div64_u64( - sample->idletime_us * 100, - sample->duration_us); core_pct = div64_u64(sample->aperf * 100, sample->mperf); sample->freq = cpu->pstate.max_pstate * core_pct * 1000; - sample->core_pct_busy = div_s64((sample->pstate_pct_busy * core_pct), - 100); + sample->core_pct_busy = core_pct; } static inline void intel_pstate_sample(struct cpudata *cpu) { - ktime_t now; - u64 idle_time_us; u64 aperf, mperf; - now = ktime_get(); - idle_time_us = get_cpu_idle_time_us(cpu->cpu, NULL); - rdmsrl(MSR_IA32_APERF, aperf); rdmsrl(MSR_IA32_MPERF, mperf); - /* for the first sample, don't actually record a sample, just - * set the baseline */ - if (cpu->prev_idle_time_us > 0) { - cpu->sample_ptr = (cpu->sample_ptr + 1) % SAMPLE_COUNT; - cpu->samples[cpu->sample_ptr].start_time = cpu->prev_sample; - cpu->samples[cpu->sample_ptr].end_time = now; - cpu->samples[cpu->sample_ptr].duration_us = - ktime_us_delta(now, cpu->prev_sample); - cpu->samples[cpu->sample_ptr].idletime_us = - idle_time_us - cpu->prev_idle_time_us; - - cpu->samples[cpu->sample_ptr].aperf = aperf; - cpu->samples[cpu->sample_ptr].mperf = mperf; - cpu->samples[cpu->sample_ptr].aperf -= cpu->prev_aperf; - cpu->samples[cpu->sample_ptr].mperf -= cpu->prev_mperf; + cpu->sample_ptr = (cpu->sample_ptr + 1) % SAMPLE_COUNT; + cpu->samples[cpu->sample_ptr].aperf = aperf; + cpu->samples[cpu->sample_ptr].mperf = mperf; + cpu->samples[cpu->sample_ptr].aperf -= cpu->prev_aperf; + cpu->samples[cpu->sample_ptr].mperf -= cpu->prev_mperf; - intel_pstate_calc_busy(cpu, &cpu->samples[cpu->sample_ptr]); - } + intel_pstate_calc_busy(cpu, &cpu->samples[cpu->sample_ptr]); - cpu->prev_sample = now; - cpu->prev_idle_time_us = idle_time_us; cpu->prev_aperf = aperf; cpu->prev_mperf = mperf; } -- 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/