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authorChristian Ehrhardt <ehrhardt@linux.vnet.ibm.com>2009-11-30 12:16:47 +0100
committerIngo Molnar <mingo@elte.hu>2009-12-09 10:04:01 +0100
commit1983a922a1bc843806b9a36cf3a370b242783140 (patch)
tree3071f23d39e05587823a40033c4c11a0867dd46e /kernel/sched.c
parent0bcdcf28c979869f44e05121b96ff2cfb05bd8e6 (diff)
downloadop-kernel-dev-1983a922a1bc843806b9a36cf3a370b242783140.zip
op-kernel-dev-1983a922a1bc843806b9a36cf3a370b242783140.tar.gz
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 <ehrhardt@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1259579808-11357-3-git-send-email-ehrhardt@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/sched.c')
-rw-r--r--kernel/sched.c15
1 files changed, 14 insertions, 1 deletions
diff --git a/kernel/sched.c b/kernel/sched.c
index b54ecf8..116efed 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)
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