Messages in this thread Patch in this message | ![/](/images/icornerl.gif) | | From | Qais Yousef <> | Subject | [PATCH 2/3] sched/pelt: Add a new function to approximate runtime to reach given util | Date | Mon, 5 Feb 2024 22:33:43 +0000 |
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It is basically the ramp-up time from 0 to a given value. Will be used later to help remove magic margins with something more deterministic.
Signed-off-by: Qais Yousef <qyousef@layalina.io> --- 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 81555a8288be..00a1b9c1bf16 100644 --- a/kernel/sched/pelt.c +++ b/kernel/sched/pelt.c @@ -487,3 +487,24 @@ 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 1c15ff5ef5a4..d078e6481bd0 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -3003,6 +3003,7 @@ 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
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