From: Juri Lelli <juri.lelli@redhat.com>
To: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Cc: tglx@linutronix.de, mingo@redhat.com, peterz@infradead.org,
bp@suse.de, lenb@kernel.org, rjw@rjwysocki.net,
mgorman@techsingularity.net, x86@kernel.org,
linux-pm@vger.kernel.org, viresh.kumar@linaro.org,
linux-kernel@vger.kernel.org
Subject: Re: [RFC/RFT] [PATCH 02/10] cpufreq: intel_pstate: Conditional frequency invariant accounting
Date: Wed, 16 May 2018 17:19:25 +0200 [thread overview]
Message-ID: <20180516151925.GO28366@localhost.localdomain> (raw)
In-Reply-To: <20180516044911.28797-3-srinivas.pandruvada@linux.intel.com>
On 15/05/18 21:49, Srinivas Pandruvada wrote:
> 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 <srinivas.pandruvada@linux.intel.com>
> ---
> [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();
This will unconditionally trigger the reading/calculation at each tick
even though information is not actually consumed (e.g., running
performance or any other governor), right? Do we want that?
Anyway, FWIW I started testing this on a E5-2609 v3 and I'm not seeing
hackbench regressions so far (running with schedutil governor).
Best,
- Juri
next prev parent reply other threads:[~2018-05-16 15:19 UTC|newest]
Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-16 4:49 [RFC/RFT] [PATCH 00/10] Intel_pstate: HWP Dynamic performance boost Srinivas Pandruvada
2018-05-16 4:49 ` [RFC/RFT] [PATCH 01/10] x86,sched: Add support for frequency invariance Srinivas Pandruvada
2018-05-16 9:56 ` Peter Zijlstra
2018-05-16 4:49 ` [RFC/RFT] [PATCH 02/10] cpufreq: intel_pstate: Conditional frequency invariant accounting Srinivas Pandruvada
2018-05-16 7:16 ` Peter Zijlstra
2018-05-16 7:29 ` Peter Zijlstra
2018-05-16 9:07 ` Rafael J. Wysocki
2018-05-16 17:32 ` Srinivas Pandruvada
2018-05-16 15:19 ` Juri Lelli [this message]
2018-05-16 15:47 ` Peter Zijlstra
2018-05-16 16:31 ` Juri Lelli
2018-05-17 10:59 ` Juri Lelli
2018-05-17 15:04 ` Juri Lelli
2018-05-17 15:41 ` Srinivas Pandruvada
2018-05-17 16:16 ` Peter Zijlstra
2018-05-17 16:42 ` Srinivas Pandruvada
2018-05-17 16:56 ` Rafael J. Wysocki
2018-05-17 18:28 ` Peter Zijlstra
2018-05-18 7:36 ` Rafael J. Wysocki
2018-05-18 10:57 ` Patrick Bellasi
2018-05-18 11:29 ` Peter Zijlstra
2018-05-18 13:33 ` Patrick Bellasi
2018-05-30 16:57 ` Patrick Bellasi
2018-05-18 14:09 ` Valentin Schneider
2018-05-16 15:58 ` Srinivas Pandruvada
2018-05-16 4:49 ` [RFC/RFT] [PATCH 03/10] cpufreq: intel_pstate: Utility functions to boost HWP performance limits Srinivas Pandruvada
2018-05-16 7:22 ` Peter Zijlstra
2018-05-16 9:15 ` Rafael J. Wysocki
2018-05-16 10:43 ` Peter Zijlstra
2018-05-16 15:39 ` Srinivas Pandruvada
2018-05-16 15:41 ` Srinivas Pandruvada
2018-05-16 4:49 ` [RFC/RFT] [PATCH 04/10] cpufreq: intel_pstate: Add update_util_hook for HWP Srinivas Pandruvada
2018-05-16 4:49 ` [RFC/RFT] [PATCH 05/10] cpufreq: intel_pstate: HWP boost performance on IO Wake Srinivas Pandruvada
2018-05-16 7:37 ` Peter Zijlstra
2018-05-16 17:55 ` Srinivas Pandruvada
2018-05-17 8:19 ` Peter Zijlstra
2018-05-16 9:45 ` Rafael J. Wysocki
2018-05-16 19:28 ` Srinivas Pandruvada
2018-05-16 4:49 ` [RFC/RFT] [PATCH 06/10] cpufreq / sched: Add interface to get utilization values Srinivas Pandruvada
2018-05-16 6:40 ` Viresh Kumar
2018-05-16 22:25 ` Srinivas Pandruvada
2018-05-16 8:11 ` Peter Zijlstra
2018-05-16 22:40 ` Srinivas Pandruvada
2018-05-17 7:50 ` Peter Zijlstra
2018-05-16 4:49 ` [RFC/RFT] [PATCH 07/10] cpufreq: intel_pstate: HWP boost performance on busy task migrate Srinivas Pandruvada
2018-05-16 9:49 ` Rafael J. Wysocki
2018-05-16 20:59 ` Srinivas Pandruvada
2018-05-16 4:49 ` [RFC/RFT] [PATCH 08/10] cpufreq: intel_pstate: Dyanmically update busy pct Srinivas Pandruvada
2018-05-16 7:43 ` Peter Zijlstra
2018-05-16 7:47 ` Peter Zijlstra
2018-05-16 4:49 ` [RFC/RFT] [PATCH 09/10] cpufreq: intel_pstate: New sysfs entry to control HWP boost Srinivas Pandruvada
2018-05-16 4:49 ` [RFC/RFT] [PATCH 10/10] cpufreq: intel_pstate: enable boost for SKX Srinivas Pandruvada
2018-05-16 7:49 ` Peter Zijlstra
2018-05-16 15:46 ` Srinivas Pandruvada
2018-05-16 15:54 ` Peter Zijlstra
2018-05-17 0:52 ` Srinivas Pandruvada
2018-05-16 6:49 ` [RFC/RFT] [PATCH 00/10] Intel_pstate: HWP Dynamic performance boost Juri Lelli
2018-05-16 15:43 ` Srinivas Pandruvada
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