From: Thara Gopinath <thara.gopinath@linaro.org>
To: mingo@redhat.com, peterz@infradead.org, ionela.voinescu@arm.com,
vincent.guittot@linaro.org, dietmar.eggemann@arm.com,
rui.zhang@intel.com, qperret@google.com,
daniel.lezcano@linaro.org, viresh.kumar@linaro.org,
rostedt@goodmis.org, will@kernel.org, catalin.marinas@arm.com,
sudeep.holla@arm.com, juri.lelli@redhat.com, corbet@lwn.net
Cc: linux-kernel@vger.kernel.org, amit.kachhap@gmail.com,
javi.merino@kernel.org, amit.kucheria@verdurent.com
Subject: [Patch v9 7/8] sched/fair: Enable tuning of decay period
Date: Tue, 28 Jan 2020 17:36:06 -0500 [thread overview]
Message-ID: <1580250967-4386-8-git-send-email-thara.gopinath@linaro.org> (raw)
In-Reply-To: <1580250967-4386-1-git-send-email-thara.gopinath@linaro.org>
Thermal pressure follows pelt signals which means the decay period for
thermal pressure is the default pelt decay period. Depending on soc
characteristics and thermal activity, it might be beneficial to decay
thermal pressure slower, but still in-tune with the pelt signals. One way
to achieve this is to provide a command line parameter to set a decay
shift parameter to an integer between 0 and 10.
Signed-off-by: Thara Gopinath <thara.gopinath@linaro.org>
---
v8->v9:
- Initialized the __shift to 0 in setup_sched_thermal_decay_shift
as per Quentin's suggestion.
Documentation/admin-guide/kernel-parameters.txt | 5 +++++
kernel/sched/core.c | 2 +-
kernel/sched/fair.c | 15 ++++++++++++++-
kernel/sched/sched.h | 18 ++++++++++++++++++
4 files changed, 38 insertions(+), 2 deletions(-)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index e35b28e..be4147b 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -4376,6 +4376,11 @@
incurs a small amount of overhead in the scheduler
but is useful for debugging and performance tuning.
+ sched_thermal_decay_shift=
+ [KNL, SMP] Set decay shift for thermal pressure signal.
+ Format: integer between 0 and 10
+ Default is 0.
+
skew_tick= [KNL] Offset the periodic timer tick per cpu to mitigate
xtime_lock contention on larger systems, and/or RCU lock
contention on all systems with CONFIG_MAXSMP set.
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index b921795..508e64b 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -3602,7 +3602,7 @@ void scheduler_tick(void)
update_rq_clock(rq);
thermal_pressure = arch_cpu_thermal_pressure(cpu_of(rq));
- update_thermal_load_avg(rq_clock_task(rq), rq, thermal_pressure);
+ update_thermal_load_avg(rq_clock_thermal(rq), rq, thermal_pressure);
curr->sched_class->task_tick(rq, curr, 0);
calc_global_load_tick(rq);
psi_task_tick(rq);
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index d879077..df23564 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -86,6 +86,19 @@ static unsigned int normalized_sysctl_sched_wakeup_granularity = 1000000UL;
const_debug unsigned int sysctl_sched_migration_cost = 500000UL;
+int sched_thermal_decay_shift;
+static int __init setup_sched_thermal_decay_shift(char *str)
+{
+ int _shift = 0;
+
+ if (kstrtoint(str, 0, &_shift))
+ pr_warn("Unable to set scheduler thermal pressure decay shift parameter\n");
+
+ sched_thermal_decay_shift = clamp(_shift, 0, 10);
+ return 1;
+}
+__setup("sched_thermal_decay_shift=", setup_sched_thermal_decay_shift);
+
#ifdef CONFIG_SMP
/*
* For asym packing, by default the lower numbered CPU has higher priority.
@@ -7530,7 +7543,7 @@ static bool __update_blocked_others(struct rq *rq, bool *done)
decayed = update_rt_rq_load_avg(now, rq, curr_class == &rt_sched_class) |
update_dl_rq_load_avg(now, rq, curr_class == &dl_sched_class) |
- update_thermal_load_avg(rq_clock_task(rq), rq, thermal_pressure) |
+ update_thermal_load_avg(rq_clock_thermal(rq), rq, thermal_pressure) |
update_irq_load_avg(rq, 0);
if (others_have_blocked(rq))
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 1f256cb..acd32bf 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -1110,6 +1110,24 @@ static inline u64 rq_clock_task(struct rq *rq)
return rq->clock_task;
}
+/**
+ * By default the decay is the default pelt decay period.
+ * The decay shift can change the decay period in
+ * multiples of 32.
+ * Decay shift Decay period(ms)
+ * 0 32
+ * 1 64
+ * 2 128
+ * 3 256
+ * 4 512
+ */
+extern int sched_thermal_decay_shift;
+
+static inline u64 rq_clock_thermal(struct rq *rq)
+{
+ return rq_clock_task(rq) >> sched_thermal_decay_shift;
+}
+
static inline void rq_clock_skip_update(struct rq *rq)
{
lockdep_assert_held(&rq->lock);
--
2.1.4
next prev parent reply other threads:[~2020-01-28 22:36 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-28 22:35 [Patch v9 0/8] Introduce Thermal Pressure Thara Gopinath
2020-01-28 22:36 ` [Patch v9 1/8] sched/pelt: Add support to track thermal pressure Thara Gopinath
2020-02-13 12:29 ` Amit Kucheria
2020-02-13 14:11 ` Thara Gopinath
2020-02-13 14:41 ` Amit Kucheria
2020-01-28 22:36 ` [Patch v9 2/8] sched/topology: Add hook to read per cpu " Thara Gopinath
2020-01-28 22:36 ` [Patch v9 3/8] arm,arm64,drivers:Add infrastructure to store and update instantaneous " Thara Gopinath
2020-02-13 12:25 ` Amit Kucheria
2020-02-13 14:05 ` Thara Gopinath
2020-02-13 14:38 ` Amit Kucheria
2020-02-14 15:01 ` Thara Gopinath
2020-01-28 22:36 ` [Patch v9 4/8] sched/fair: Enable periodic update of average " Thara Gopinath
2020-01-28 22:36 ` [Patch v9 5/8] sched/fair: update cpu_capacity to reflect " Thara Gopinath
2020-02-13 12:47 ` Amit Kucheria
2020-02-13 14:12 ` Thara Gopinath
2020-02-13 13:39 ` Amit Kucheria
2020-02-14 14:52 ` Thara Gopinath
2020-01-28 22:36 ` [Patch v9 6/8] thermal/cpu-cooling: Update thermal pressure in case of a maximum frequency capping Thara Gopinath
2020-01-28 22:36 ` Thara Gopinath [this message]
2020-01-28 23:56 ` [Patch v9 7/8] sched/fair: Enable tuning of decay period Randy Dunlap
2020-02-03 12:07 ` Thara Gopinath
2020-02-03 15:55 ` Peter Zijlstra
2020-02-04 8:39 ` Dietmar Eggemann
2020-02-07 22:42 ` Thara Gopinath
2020-02-10 11:59 ` Dietmar Eggemann
2020-02-13 13:54 ` Thara Gopinath
2020-02-14 10:26 ` Dietmar Eggemann
2020-02-18 14:57 ` Thara Gopinath
2020-02-19 9:14 ` Dietmar Eggemann
2020-01-28 22:36 ` [Patch v9 8/8] arm64: Enable averaging of thermal pressure for arm64 based SoCs Thara Gopinath
2020-02-03 8:59 ` Dietmar Eggemann
2020-02-10 12:07 ` [Patch v9 0/8] Introduce Thermal Pressure Dietmar Eggemann
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