linux-kernel - [patch v6 06/21] sched: log the cpu utilization at rq

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <1364654108-16307-7-git-send-email-alex.shi@intel.com>
Date:	Sat, 30 Mar 2013 22:34:53 +0800
From:	Alex Shi <alex.shi@...el.com>
To:	mingo@...hat.com, peterz@...radead.org, tglx@...utronix.de,
	akpm@...ux-foundation.org, arjan@...ux.intel.com, bp@...en8.de,
	pjt@...gle.com, namhyung@...nel.org, efault@....de
Cc:	vincent.guittot@...aro.org, gregkh@...uxfoundation.org,
	preeti@...ux.vnet.ibm.com, viresh.kumar@...aro.org,
	linux-kernel@...r.kernel.org, alex.shi@...el.com
Subject: [patch v6 06/21] sched: log the cpu utilization at rq

The cpu's utilization is to measure how busy is the cpu.
        util = cpu_rq(cpu)->avg.runnable_avg_sum * SCHED_POEWR_SCALE
                / cpu_rq(cpu)->avg.runnable_avg_period;

Since the util is no more than 1, we scale its value with 1024, same as
SCHED_POWER_SCALE and set the FULL_UTIL as 1024.

In later power aware scheduling, we are sensitive for how busy of the
cpu. Since as to power consuming, it is tight related with cpu busy
time.

BTW, rq->util can be used for any purposes if needed, not only power
scheduling.

Signed-off-by: Alex Shi <alex.shi@...el.com>
---
 include/linux/sched.h | 2 +-
 kernel/sched/debug.c  | 1 +
 kernel/sched/fair.c   | 5 +++++
 kernel/sched/sched.h  | 4 ++++
 4 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 5a4cf37..226a515 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -793,7 +793,7 @@ enum cpu_idle_type {
 #define SCHED_LOAD_SCALE	(1L << SCHED_LOAD_SHIFT)
 
 /*
- * Increase resolution of cpu_power calculations
+ * Increase resolution of cpu_power and rq->util calculations
  */
 #define SCHED_POWER_SHIFT	10
 #define SCHED_POWER_SCALE	(1L << SCHED_POWER_SHIFT)
diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
index 75024a6..f5db759 100644
--- a/kernel/sched/debug.c
+++ b/kernel/sched/debug.c
@@ -311,6 +311,7 @@ do {									\
 
 	P(ttwu_count);
 	P(ttwu_local);
+	P(util);
 
 #undef P
 #undef P64
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 90106ad..a165f52 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -1495,8 +1495,13 @@ static void update_cfs_rq_blocked_load(struct cfs_rq *cfs_rq, int force_update)
 
 static inline void update_rq_runnable_avg(struct rq *rq, int runnable)
 {
+	u32 period;
 	__update_entity_runnable_avg(rq->clock_task, &rq->avg, runnable);
 	__update_tg_runnable_avg(&rq->avg, &rq->cfs);
+
+	period = rq->avg.runnable_avg_period ? rq->avg.runnable_avg_period : 1;
+	rq->util = (u64)(rq->avg.runnable_avg_sum << SCHED_POWER_SHIFT)
+				/ period;
 }
 
 /* Add the load generated by se into cfs_rq's child load-average */
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 804ee41..8682110 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -351,6 +351,9 @@ extern struct root_domain def_root_domain;
 
 #endif /* CONFIG_SMP */
 
+/* full cpu utilization */
+#define FULL_UTIL	SCHED_POWER_SCALE
+
 /*
  * This is the main, per-CPU runqueue data structure.
  *
@@ -482,6 +485,7 @@ struct rq {
 #endif
 
 	struct sched_avg avg;
+	unsigned int util;
 };
 
 static inline int cpu_of(struct rq *rq)
-- 
1.7.12

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/