From: Ingo Molnar Date: Mon, 16 Jul 2007 07:46:30 +0000 (+0200) Subject: [PATCH] sched: improve weight-array comments X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=f9153ee6c71cb9ab38de3b8ed66b1c3fa27c3f7d;p=openwrt%2Fstaging%2Fblogic.git [PATCH] sched: improve weight-array comments improve the comments around the wmult array (which controls the weight of niced tasks). Clarify that to achieve a 10% difference in CPU utilization, a weight multiplier of 1.25 has to be used. Signed-off-by: Ingo Molnar --- diff --git a/kernel/sched.c b/kernel/sched.c index 3332bbb5d5cf..a7284bc79cdf 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -736,7 +736,9 @@ static void update_curr_load(struct rq *rq, u64 now) * * The "10% effect" is relative and cumulative: from _any_ nice level, * if you go up 1 level, it's -10% CPU usage, if you go down 1 level - * it's +10% CPU usage. + * it's +10% CPU usage. (to achieve that we use a multiplier of 1.25. + * If a task goes up by ~10% and another task goes down by ~10% then + * the relative distance between them is ~25%.) */ static const int prio_to_weight[40] = { /* -20 */ 88818, 71054, 56843, 45475, 36380, 29104, 23283, 18626, 14901, 11921,