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([146.70.179.108]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-48a8fee5033sm68064215e9.22.2026.05.03.19.00.13 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 03 May 2026 19:00:15 -0700 (PDT) From: Qais Yousef To: Ingo Molnar , Peter Zijlstra , Vincent Guittot , "Rafael J. Wysocki" , Viresh Kumar Cc: Juri Lelli , Steven Rostedt , John Stultz , Dietmar Eggemann , Tim Chen , "Chen, Yu C" , Thomas Gleixner , linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, Qais Yousef Subject: [PATCH v2 02/13] sched/pelt: Add a new function to approximate the future util_avg value Date: Mon, 4 May 2026 02:59:52 +0100 Message-Id: <20260504020003.71306-3-qyousef@layalina.io> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20260504020003.71306-1-qyousef@layalina.io> References: <20260504020003.71306-1-qyousef@layalina.io> Precedence: bulk X-Mailing-List: linux-pm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Given a util_avg value, the new function will return the future one given a runtime delta. This will be useful in later patches to help replace some magic margins with more deterministic behavior. Signed-off-by: Qais Yousef --- kernel/sched/pelt.c | 20 ++++++++++++++++++++ kernel/sched/sched.h | 1 + 2 files changed, 21 insertions(+) diff --git a/kernel/sched/pelt.c b/kernel/sched/pelt.c index 897790889ba3..5a8f4dc99ffc 100644 --- a/kernel/sched/pelt.c +++ b/kernel/sched/pelt.c @@ -488,3 +488,23 @@ bool update_other_load_avgs(struct rq *rq) update_hw_load_avg(rq_clock_task(rq), rq, hw_pressure) | update_irq_load_avg(rq, 0); } + +/* + * Approximate the new util_avg value assuming an entity has continued to run + * for @delta us. + */ +unsigned long approximate_util_avg(unsigned long util, u64 delta) +{ + struct sched_avg sa = { + .util_sum = util * PELT_MIN_DIVIDER, + .util_avg = util, + }; + + if (unlikely(!delta)) + return util; + + accumulate_sum(delta, &sa, 1, 0, 1); + ___update_load_avg(&sa, 0); + + return sa.util_avg; +} diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index c95584191d58..190515b50dc8 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -3527,6 +3527,7 @@ unsigned long sugov_effective_cpu_perf(int cpu, unsigned long actual, unsigned long min, unsigned long max); +unsigned long approximate_util_avg(unsigned long util, u64 delta); /* * Verify the fitness of task @p to run on @cpu taking into account the -- 2.34.1