From: Yuyang Du <yuyang.du@intel.com>
To: peterz@infradead.org, mingo@kernel.org, linux-kernel@vger.kernel.org
Cc: bsegall@google.com, pjt@google.com, morten.rasmussen@arm.com,
vincent.guittot@linaro.org, dietmar.eggemann@arm.com,
matt@codeblueprint.co.uk, umgwanakikbuti@gmail.com,
Yuyang Du <yuyang.du@intel.com>
Subject: [PATCH v1 01/10] sched/fair: Chance LOAD_AVG_MAX_N from 345 to 347
Date: Wed, 10 Aug 2016 08:14:46 +0800 [thread overview]
Message-ID: <1470788095-2125-2-git-send-email-yuyang.du@intel.com> (raw)
In-Reply-To: <1470788095-2125-1-git-send-email-yuyang.du@intel.com>
In commit 5b51f2f80b3b906ce59bd4dce6eca3c7f34cb1b9
Author: Paul Turner <pjt@google.com>
Date: Thu Oct 4 13:18:32 2012 +0200
sched: Make __update_entity_runnable_avg() fast
Paul has a program to compute LOAD_AVG_MAX_N, which basically means
how many periods (at least) are needed for LOAD_AVG_MAX, and the result
of calc_conv(1024) is 345:
long mult_inv(long c, int n) {
return (c * runnable_avg_yN_inv[n]) >> WMULT_SHIFT;
}
void calc_conv(long n) {
long old_n;
int i = -1;
printf("convergence (LOAD_AVG_MAX, LOAD_AVG_MAX_N)\n");
do {
old_n = n;
n = mult_inv(n, 1) + 1024;
i++;
} while (n != old_n);
printf("%d> %ld\n", i - 1, n);
printf("\n");
}
The initial value of i is -1, which should be 1 as far as I can tell.
Accordingly, the final result of LOAD_AVG_MAX_N should be changed
from 345 to 347.
Signed-off-by: Yuyang Du <yuyang.du@intel.com>
---
kernel/sched/fair.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 4088eed..997297b 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -666,7 +666,7 @@ static unsigned long task_h_load(struct task_struct *p);
*/
#define LOAD_AVG_PERIOD 32
#define LOAD_AVG_MAX 47742 /* maximum possible load avg */
-#define LOAD_AVG_MAX_N 345 /* number of full periods to produce LOAD_AVG_MAX */
+#define LOAD_AVG_MAX_N 347 /* number of full periods to produce LOAD_AVG_MAX */
/* Give new sched_entity start runnable values to heavy its load in infant time */
void init_entity_runnable_average(struct sched_entity *se)
--
1.7.9.5
next prev parent reply other threads:[~2016-08-10 18:36 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-10 0:14 [PATCH v1 00/10] Optimize sched avgs computation and implement flat util hierarchy Yuyang Du
2016-08-10 0:14 ` Yuyang Du [this message]
2016-08-24 16:01 ` [PATCH v1 01/10] sched/fair: Chance LOAD_AVG_MAX_N from 345 to 347 Vincent Guittot
2016-08-29 0:07 ` Yuyang Du
2016-08-10 0:14 ` [PATCH v1 02/10] documentation: Add scheduler/sched-avg.txt Yuyang Du
2016-08-22 16:48 ` Randy Dunlap
2016-08-10 0:14 ` [PATCH v1 03/10] sched/fair: Add static to remove_entity_load_avg() Yuyang Du
2016-08-10 0:14 ` [PATCH v1 04/10] sched/fair: Rename variable names for sched averages Yuyang Du
2016-08-10 0:14 ` [PATCH v1 05/10] sched/fair: Add __always_inline compiler attribute to __accumulate_sum() Yuyang Du
2016-08-10 0:14 ` [PATCH v1 06/10] sched/fair: Optimize __update_sched_avg() Yuyang Du
2016-08-10 0:14 ` [PATCH v1 07/10] sched/fair: Remove useless 64-bit to 32-bit variable conversion Yuyang Du
2016-08-25 7:11 ` Vincent Guittot
2016-08-29 1:00 ` Yuyang Du
2016-08-10 0:14 ` [PATCH v1 08/10] sched/fair: Remove scale_load_down() for load_avg Yuyang Du
2016-08-10 0:14 ` [PATCH v1 09/10] sched/fair: Rename scale_load() and scale_load_down() Yuyang Du
2016-08-10 0:14 ` [PATCH v1 10/10] sched/fair: Implement flat hierarchical structure for util_avg Yuyang Du
2016-08-10 0:23 ` [PATCH v1 00/10] Optimize sched avgs computation and implement flat util hierarchy Yuyang Du
2016-08-22 23:26 ` Yuyang Du
2016-08-23 13:28 ` Vincent Guittot
2016-08-23 14:13 ` Peter Zijlstra
2016-08-23 14:45 ` Vincent Guittot
2016-08-23 15:39 ` Dietmar Eggemann
2016-08-29 1:37 ` Yuyang Du
2016-09-01 18:32 ` Dietmar Eggemann
2016-08-24 8:54 ` Morten Rasmussen
2016-08-24 9:48 ` Vincent Guittot
2016-08-29 19:00 ` Yuyang Du
2016-09-01 14:22 ` Morten Rasmussen
2016-08-23 19:09 ` Yuyang Du
2016-08-23 19:01 ` Yuyang Du
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