On 2019.07.21 23:52 Viresh Kumar wrote:
To avoid reducing the frequency of a CPU prematurely, we skip reducing the frequency if the CPU had been busy recently.
This should not be done when the limits of the policy are changed, for example due to thermal throttling. We should always get the frequency within limits as soon as possible.
Fixes: ecd288429126 ("cpufreq: schedutil: Don't set next_freq to UINT_MAX") Cc: v4.18+ stable@vger.kernel.org # v4.18+ Reported-by: Doug Smythies doug.smythies@gmail.com Signed-off-by: Viresh Kumar viresh.kumar@linaro.org
@Doug: Please try this patch, it must fix the issue you reported.
It fixes the driver = acpi-cpufreq ; governor = schedutil test case It does not fix the driver = intel_cpufreq ; governor = schedutil test case
I have checked my results twice, but will check again in the day or two.
... Doug
kernel/sched/cpufreq_schedutil.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c index 636ca6f88c8e..b53c4f02b0f1 100644 --- a/kernel/sched/cpufreq_schedutil.c +++ b/kernel/sched/cpufreq_schedutil.c @@ -447,7 +447,7 @@ static void sugov_update_single(struct update_util_data *hook, u64 time, struct sugov_policy *sg_policy = sg_cpu->sg_policy; unsigned long util, max; unsigned int next_f;
- bool busy;
bool busy = false;
sugov_iowait_boost(sg_cpu, time, flags); sg_cpu->last_update = time;
@@ -457,7 +457,9 @@ static void sugov_update_single(struct update_util_data *hook, u64 time, if (!sugov_should_update_freq(sg_policy, time)) return;
- busy = sugov_cpu_is_busy(sg_cpu);
/* Limits may have changed, don't skip frequency update */
if (!sg_policy->need_freq_update)
busy = sugov_cpu_is_busy(sg_cpu);util = sugov_get_util(sg_cpu); max = sg_cpu->max;
-- 2.21.0.rc0.269.g1a574e7a288b