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([146.70.179.108]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-48a8fee5033sm68064215e9.22.2026.05.03.19.00.16 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 03 May 2026 19:00:17 -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 03/13] sched/pelt: Add a new function to approximate runtime to reach given util Date: Mon, 4 May 2026 02:59:53 +0100 Message-Id: <20260504020003.71306-4-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 It is basically the ramp-up time from 0 to a given value. Will be used later to implement new tunable to control response time for schedutil. Signed-off-by: Qais Yousef --- kernel/sched/pelt.c | 21 +++++++++++++++++++++ kernel/sched/sched.h | 1 + 2 files changed, 22 insertions(+) diff --git a/kernel/sched/pelt.c b/kernel/sched/pelt.c index 5a8f4dc99ffc..dbd450798b03 100644 --- a/kernel/sched/pelt.c +++ b/kernel/sched/pelt.c @@ -508,3 +508,24 @@ unsigned long approximate_util_avg(unsigned long util, u64 delta) return sa.util_avg; } + +/* + * Approximate the required amount of runtime in ms required to reach @util. + */ +u64 approximate_runtime(unsigned long util) +{ + struct sched_avg sa = {}; + u64 delta = 1024; // period = 1024 = ~1ms + u64 runtime = 0; + + if (unlikely(!util)) + return runtime; + + while (sa.util_avg < util) { + accumulate_sum(delta, &sa, 1, 0, 1); + ___update_load_avg(&sa, 0); + runtime++; + } + + return runtime; +} diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 190515b50dc8..a445add5cc3a 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -3528,6 +3528,7 @@ unsigned long sugov_effective_cpu_perf(int cpu, unsigned long actual, unsigned long max); unsigned long approximate_util_avg(unsigned long util, u64 delta); +u64 approximate_runtime(unsigned long util); /* * Verify the fitness of task @p to run on @cpu taking into account the -- 2.34.1