Messages in this thread Patch in this message | | | From | Claudio Scordino <> | Subject | [PATCH] cpufreq: schedutil: rate limits for SCHED_DEADLINE | Date | Thu, 8 Feb 2018 18:01:42 +0100 |
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When the SCHED_DEADLINE scheduling class increases the CPU utilization, we should not wait for the rate limit, otherwise we may miss some deadline.
Tests using rt-app on Exynos5422 have shown reductions of about 10% of deadline misses for tasks with low RT periods.
The patch applies on top of the one recently proposed by Peter to drop the SCHED_CPUFREQ_* flags.
Signed-off-by: Claudio Scordino <claudio@evidence.eu.com> CC: Rafael J . Wysocki <rafael.j.wysocki@intel.com> CC: Patrick Bellasi <patrick.bellasi@arm.com> CC: Dietmar Eggemann <dietmar.eggemann@arm.com> CC: Morten Rasmussen <morten.rasmussen@arm.com> CC: Juri Lelli <juri.lelli@redhat.com> CC: Viresh Kumar <viresh.kumar@linaro.org> CC: Vincent Guittot <vincent.guittot@linaro.org> CC: Todd Kjos <tkjos@android.com> CC: Joel Fernandes <joelaf@google.com> CC: linux-pm@vger.kernel.org CC: linux-kernel@vger.kernel.org --- kernel/sched/cpufreq_schedutil.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-)
diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c index b0bd77d..d8dcba2 100644 --- a/kernel/sched/cpufreq_schedutil.c +++ b/kernel/sched/cpufreq_schedutil.c @@ -74,7 +74,10 @@ static DEFINE_PER_CPU(struct sugov_cpu, sugov_cpu); /************************ Governor internals ***********************/ -static bool sugov_should_update_freq(struct sugov_policy *sg_policy, u64 time) +static bool sugov_should_update_freq(struct sugov_policy *sg_policy, + u64 time, + struct sugov_cpu *sg_cpu_old, + struct sugov_cpu *sg_cpu_new) { s64 delta_ns; @@ -111,6 +114,10 @@ static bool sugov_should_update_freq(struct sugov_policy *sg_policy, u64 time) return true; } + /* Ignore rate limit when DL increased utilization. */ + if (sg_cpu_new->util_dl > sg_cpu_old->util_dl) + return true; + delta_ns = time - sg_policy->last_freq_update_time; return delta_ns >= sg_policy->freq_update_delay_ns; } @@ -271,6 +278,7 @@ static void sugov_update_single(struct update_util_data *hook, u64 time, unsigned int flags) { struct sugov_cpu *sg_cpu = container_of(hook, struct sugov_cpu, update_util); + struct sugov_cpu sg_cpu_old = *sg_cpu; struct sugov_policy *sg_policy = sg_cpu->sg_policy; unsigned long util, max; unsigned int next_f; @@ -279,7 +287,7 @@ static void sugov_update_single(struct update_util_data *hook, u64 time, sugov_set_iowait_boost(sg_cpu, time, flags); sg_cpu->last_update = time; - if (!sugov_should_update_freq(sg_policy, time)) + if (!sugov_should_update_freq(sg_policy, time, &sg_cpu_old, sg_cpu)) return; busy = sugov_cpu_is_busy(sg_cpu); @@ -350,6 +358,7 @@ static void sugov_update_shared(struct update_util_data *hook, u64 time, unsigned int flags) { struct sugov_cpu *sg_cpu = container_of(hook, struct sugov_cpu, update_util); + struct sugov_cpu sg_cpu_old = *sg_cpu; struct sugov_policy *sg_policy = sg_cpu->sg_policy; unsigned int next_f; @@ -359,7 +368,7 @@ static void sugov_update_shared(struct update_util_data *hook, u64 time, sugov_set_iowait_boost(sg_cpu, time, flags); sg_cpu->last_update = time; - if (sugov_should_update_freq(sg_policy, time)) { + if (sugov_should_update_freq(sg_policy, time, &sg_cpu_old, sg_cpu)) { next_f = sugov_next_freq_shared(sg_cpu, time); sugov_update_commit(sg_policy, time, next_f); } -- 2.7.4
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