Messages in this thread Patch in this message | | | From | Yuyang Du <> | 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 |
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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
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