Given that a CPU's clock is gated at even the shallowest idle state,
waiting until a CPU idles at least once before reducing its frequency is
putting the cart before the horse. For long-running workloads with low
compute needs, requiring an idle call since the last frequency update to
lower the CPU's frequency results in significantly increased energy usage.
Given that there is already a mechanism in place to ratelimit frequency
changes, this heuristic is wholly unnecessary.
Allow single-CPU performance domains to drop their frequency without
requiring an idle call in between to improve energy. Right off the bat,
this reduces CPU power consumption by 7.5% playing a cat gif in Firefox on
a Pixel 8 (270 mW -> 250 mW). And there is no visible loss of performance.
Signed-off-by: Sultan Alsawaf <sultan@kerneltoast.com>
If the last CPU frequency selected isn't set before a new CPU frequency
selection arrives, then use the new selection immediately to avoid using a
stale frequency choice. This improves both performance and energy by more
closely tracking the scheduler's latest decisions.
Signed-off-by: Sultan Alsawaf <sultan@kerneltoast.com>
Restricting sugov kthreads to their respective CPUFreq policy's CPUs slows
down schedutil's ability to switch frequencies. When DVFS is allowed from
any CPU, allow respective sugov kthreads to run on any CPU for better
performance.
Signed-off-by: Sultan Alsawaf <sultan@kerneltoast.com>
The schedutil governor reduces frequencies too fast in some
situations which cases undesirable performance drops to
appear.
To address that issue, make schedutil reduce the frequency slower by
setting it to the average of the value chosen during the previous
iteration of governor computations and the new one coming from its
frequency selection formula.
Link: https://bugzilla.kernel.org/show_bug.cgi?id=194963
Reported-by: John <john.ettedgui@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Cykeek <Cykeek@proton.me>
Signed-off-by: negrroo <mohammedaelnaggar1@gmail.com>
Signed-off-by: priiii1808 <priyanshusinghal0818@gmail.com>
