From 5714d2de93fbb156c5e45fb101a2b4f0cae8fbb7 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Mon, 16 Jul 2007 09:46:31 +0200 Subject: [PATCH] [PATCH] sched: document prio_to_wmult[] document prio_to_wmult[]. Signed-off-by: Ingo Molnar --- kernel/sched.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/kernel/sched.c b/kernel/sched.c index a7284bc79cdf..90d22b72cf81 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -748,6 +748,13 @@ static const int prio_to_weight[40] = { /* 10 */ 110, 87, 70, 56, 45, 36, 29, 23, 18, 15, }; +/* + * Inverse (2^32/x) values of the prio_to_weight[] array, precalculated. + * + * In cases where the weight does not change often, we can use the + * precalculated inverse to speed up arithmetics by turning divisions + * into multiplications: + */ static const u32 prio_to_wmult[40] = { 48356, 60446, 75558, 94446, 118058, 147573, 184467, 230589, 288233, 360285, 450347,