From patchwork Fri Mar 7 19:39:34 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Rafael J. 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Wysocki" To: Linux PM Cc: LKML , Lukasz Luba , Peter Zijlstra , Srinivas Pandruvada , Dietmar Eggemann , Morten Rasmussen , Vincent Guittot , Ricardo Neri , Pierre Gondois , Christian Loehle , Viresh Kumar Subject: [RFC][PATCH v0.3 5/6] PM: EM: Introduce em_adjust_cpu_capacity() Date: Fri, 07 Mar 2025 20:39:34 +0100 Message-ID: <2446858.NG923GbCHz@rjwysocki.net> In-Reply-To: <22640172.EfDdHjke4D@rjwysocki.net> References: <22640172.EfDdHjke4D@rjwysocki.net> Precedence: bulk X-Mailing-List: linux-pm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-CLIENT-IP: 195.136.19.94 X-CLIENT-HOSTNAME: 195.136.19.94 X-VADE-SPAMSTATE: clean X-VADE-SPAMCAUSE: gggruggvucftvghtrhhoucdtuddrgeefvddrtddtgdduudduheegucetufdoteggodetrfdotffvucfrrhhofhhilhgvmecujffqoffgrffnpdggtffipffknecuuegrihhlohhuthemucduhedtnecusecvtfgvtghiphhivghnthhsucdlqddutddtmdenucfjughrpefhvfevufffkfgjfhgggfgtsehtufertddttdejnecuhfhrohhmpedftfgrfhgrvghlucflrdcuhgihshhotghkihdfuceorhhjfiesrhhjfiihshhotghkihdrnhgvtheqnecuggftrfgrthhtvghrnhepvdffueeitdfgvddtudegueejtdffteetgeefkeffvdeftddttdeuhfegfedvjefhnecukfhppeduleehrddufeeirdduledrleegnecuvehluhhsthgvrhfuihiivgeptdenucfrrghrrghmpehinhgvthepudelhedrudefiedrudelrdelgedphhgvlhhopehkrhgvrggthhgvrhdrlhhotggrlhhnvghtpdhmrghilhhfrhhomheprhhjfiesrhhjfiihshhotghkihdrnhgvthdpnhgspghrtghpthhtohepuddvpdhrtghpthhtoheplhhinhhugidqphhmsehvghgvrhdrkhgvrhhnvghlrdhorhhgpdhrtghpthhtoheplhhinhhugidqkhgvrhhnvghlsehvghgvrhdrkhgvrhhnvghlrdhorhhgpdhrtghpthhtoheplhhukhgrshiirdhluhgsrgesrghrmhdrtghomhdprhgtphhtthhopehpvghtvghriiesihhnfhhrrgguvggrugdrohhrghdprhgtphhtthhopehsrhhinhhivhgrshdrphgrnhgurhhuvhgruggrsehlihhnuhigrdh X-DCC--Metrics: v370.home.net.pl 1024; Body=12 Fuz1=12 Fuz2=12 From: Rafael J. Wysocki Add a function for updating the Energy Model for a CPU after its capacity has changed, which subsequently will be used by the intel_pstate driver. An EM_PERF_DOMAIN_ARTIFICIAL check is added to em_adjust_new_capacity() to prevent it from calling em_compute_costs() for an "artificial" perf domain with a NULL cb parameter which would cause it to crash. Signed-off-by: Rafael J. Wysocki --- Note that this function is needed because the performance level values in the EM "state" table need to be adjusted on CPU capacity changes. In the intel_pstate case the cost values associated with them don't change because they are artificial anyway, so replacing the entire table just in order to update the performance level values is a bit wasteful, but it seems to be an exception (in the other cases when the CPU capacity changes, the cost values change too AFAICS). --- include/linux/energy_model.h | 2 ++ kernel/power/energy_model.c | 28 ++++++++++++++++++++++++---- 2 files changed, 26 insertions(+), 4 deletions(-) --- a/include/linux/energy_model.h +++ b/include/linux/energy_model.h @@ -179,6 +179,7 @@ int em_dev_update_chip_binning(struct device *dev); int em_update_performance_limits(struct em_perf_domain *pd, unsigned long freq_min_khz, unsigned long freq_max_khz); +void em_adjust_cpu_capacity(unsigned int cpu); void em_rebuild_sched_domains(void); /** @@ -405,6 +406,7 @@ { return -EINVAL; } +void em_adjust_cpu_capacity(unsigned int cpu) {} static inline void em_rebuild_sched_domains(void) {} #endif --- a/kernel/power/energy_model.c +++ b/kernel/power/energy_model.c @@ -698,10 +698,12 @@ { int ret; - ret = em_compute_costs(dev, em_table->state, NULL, pd->nr_perf_states, - pd->flags); - if (ret) - goto free_em_table; + if (!(pd->flags & EM_PERF_DOMAIN_ARTIFICIAL)) { + ret = em_compute_costs(dev, em_table->state, NULL, + pd->nr_perf_states, pd->flags); + if (ret) + goto free_em_table; + } ret = em_dev_update_perf_domain(dev, em_table); if (ret) @@ -751,6 +753,24 @@ em_recalc_and_update(dev, pd, em_table); } +/** + * em_adjust_cpu_capacity() - Adjust the EM for a CPU after a capacity update. + * @cpu: Target CPU. + * + * Adjust the existing EM for @cpu after a capacity update under the assumption + * that the capacity has been updated in the same way for all of the CPUs in + * the same perf domain. + */ +void em_adjust_cpu_capacity(unsigned int cpu) +{ + struct device *dev = get_cpu_device(cpu); + struct em_perf_domain *pd; + + pd = em_pd_get(dev); + if (pd) + em_adjust_new_capacity(cpu, dev, pd); +} + static void em_check_capacity_update(void) { cpumask_var_t cpu_done_mask;