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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_fair.c
parent0bcdcf28c979869f44e05121b96ff2cfb05bd8e6 (diff)
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_fair.c')
-rw-r--r--kernel/sched_fair.c13
1 files changed, 13 insertions, 0 deletions
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index 71b3458245e5..455106d318a8 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -21,6 +21,7 @@
*/
#include <linux/latencytop.h>
+#include <linux/sched.h>
/*
* Targeted preemption latency for CPU-bound tasks:
@@ -38,6 +39,18 @@ unsigned int sysctl_sched_latency = 5000000ULL;
unsigned int normalized_sysctl_sched_latency = 5000000ULL;
/*
+ * The initial- and re-scaling of tunables is configurable
+ * (default SCHED_TUNABLESCALING_LOG = *(1+ilog(ncpus))
+ *
+ * Options are:
+ * SCHED_TUNABLESCALING_NONE - unscaled, always *1
+ * SCHED_TUNABLESCALING_LOG - scaled logarithmical, *1+ilog(ncpus)
+ * SCHED_TUNABLESCALING_LINEAR - scaled linear, *ncpus
+ */
+enum sched_tunable_scaling sysctl_sched_tunable_scaling
+ = SCHED_TUNABLESCALING_LOG;
+
+/*
* Minimal preemption granularity for CPU-bound tasks:
* (default: 1 msec * (1 + ilog(ncpus)), units: nanoseconds)
*/