From 1983a922a1bc843806b9a36cf3a370b242783140 Mon Sep 17 00:00:00 2001 From: Christian Ehrhardt Date: Mon, 30 Nov 2009 12:16:47 +0100 Subject: sched: Make tunable scaling style configurable As scaling now takes place on all kind of cpu add/remove events a user that configures values via proc should be able to configure if his set values are still rescaled or kept whatever happens. As the comments state that log2 was just a second guess that worked the interface is not just designed for on/off, but to choose a scaling type. Currently this allows none, log and linear, but more important it allwos us to keep the interface even if someone has an even better idea how to scale the values. Signed-off-by: Christian Ehrhardt Signed-off-by: Peter Zijlstra LKML-Reference: <1259579808-11357-3-git-send-email-ehrhardt@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar --- kernel/sched.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) (limited to 'kernel/sched.c') diff --git a/kernel/sched.c b/kernel/sched.c index b54ecf84b6b..116efed962c 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -7033,7 +7033,20 @@ cpumask_var_t nohz_cpu_mask; static void update_sysctl(void) { unsigned int cpus = min(num_online_cpus(), 8U); - unsigned int factor = 1 + ilog2(cpus); + unsigned int factor; + + switch (sysctl_sched_tunable_scaling) { + case SCHED_TUNABLESCALING_NONE: + factor = 1; + break; + case SCHED_TUNABLESCALING_LINEAR: + factor = cpus; + break; + case SCHED_TUNABLESCALING_LOG: + default: + factor = 1 + ilog2(cpus); + break; + } #define SET_SYSCTL(name) \ (sysctl_##name = (factor) * normalized_sysctl_##name) -- cgit v1.2.3