From mboxrd@z Thu Jan 1 00:00:00 1970 From: Srinivas Pandruvada Subject: [RFC/RFT] [PATCH 02/10] cpufreq: intel_pstate: Conditional frequency invariant accounting Date: Tue, 15 May 2018 21:49:03 -0700 Message-ID: <20180516044911.28797-3-srinivas.pandruvada@linux.intel.com> References: <20180516044911.28797-1-srinivas.pandruvada@linux.intel.com> Return-path: In-Reply-To: <20180516044911.28797-1-srinivas.pandruvada@linux.intel.com> Sender: linux-kernel-owner@vger.kernel.org To: srinivas.pandruvada@linux.intel.com, tglx@linutronix.de, mingo@redhat.com, peterz@infradead.org, bp@suse.de, lenb@kernel.org, rjw@rjwysocki.net, mgorman@techsingularity.net Cc: x86@kernel.org, linux-pm@vger.kernel.org, viresh.kumar@linaro.org, juri.lelli@arm.com, linux-kernel@vger.kernel.org List-Id: linux-pm@vger.kernel.org intel_pstate has two operating modes: active and passive. In "active" mode, the in-built scaling governor is used and in "passive" mode, the driver can be used with any governor like "schedutil". In "active" mode the utilization values from schedutil is not used and there is a requirement from high performance computing use cases, not to read any APERF/MPERF MSRs. In this case no need to use CPU cycles for frequency invariant accounting by reading APERF/MPERF MSRs. With this change frequency invariant account is only enabled in "passive" mode. Signed-off-by: Srinivas Pandruvada --- [Note: The tick will be enabled later in the series when hwp dynamic boost is enabled] drivers/cpufreq/intel_pstate.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c index 17e566af..f686bbe 100644 --- a/drivers/cpufreq/intel_pstate.c +++ b/drivers/cpufreq/intel_pstate.c @@ -2040,6 +2040,8 @@ static int intel_pstate_register_driver(struct cpufreq_driver *driver) { int ret; + x86_arch_scale_freq_tick_disable(); + memset(&global, 0, sizeof(global)); global.max_perf_pct = 100; @@ -2052,6 +2054,9 @@ static int intel_pstate_register_driver(struct cpufreq_driver *driver) global.min_perf_pct = min_perf_pct_min(); + if (driver == &intel_cpufreq) + x86_arch_scale_freq_tick_enable(); + return 0; } -- 2.9.5