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authorPeter Zijlstra <a.p.zijlstra@chello.nl>2009-09-16 08:28:30 +0200
committerIngo Molnar <mingo@elte.hu>2009-09-16 08:42:40 +0200
commit59abf02644c45f1591e1374ee7bb45dc757fcb88 (patch)
treece9cb0a4a57873b9d7d75cce4d28308019367192
parente69b0f1b41c0e57bb1e29100b5810a5914efcb45 (diff)
downloadop-kernel-dev-59abf02644c45f1591e1374ee7bb45dc757fcb88.zip
op-kernel-dev-59abf02644c45f1591e1374ee7bb45dc757fcb88.tar.gz
sched: Add SD_PREFER_LOCAL
And turn it on for NUMA and MC domains. This improves locality in balancing decisions by keeping up to capacity amount of tasks local before looking for idle CPUs. (and twice the capacity if SD_POWERSAVINGS_BALANCE is set.) Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
-rw-r--r--include/linux/sched.h2
-rw-r--r--include/linux/topology.h2
-rw-r--r--kernel/sched_fair.c7
3 files changed, 8 insertions, 3 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h
index ee1f889..b4a39bb 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -805,7 +805,7 @@ enum cpu_idle_type {
#define SD_BALANCE_FORK 0x0008 /* Balance on fork, clone */
#define SD_BALANCE_WAKE 0x0010 /* Balance on wakeup */
#define SD_WAKE_AFFINE 0x0020 /* Wake task to waking CPU */
-
+#define SD_PREFER_LOCAL 0x0040 /* Prefer to keep tasks local to this domain */
#define SD_SHARE_CPUPOWER 0x0080 /* Domain members share cpu power */
#define SD_POWERSAVINGS_BALANCE 0x0100 /* Balance for power savings */
#define SD_SHARE_PKG_RESOURCES 0x0200 /* Domain members share cpu pkg resources */
diff --git a/include/linux/topology.h b/include/linux/topology.h
index 936ab2b..a6614b0 100644
--- a/include/linux/topology.h
+++ b/include/linux/topology.h
@@ -129,6 +129,7 @@ int arch_update_cpu_topology(void);
| 1*SD_BALANCE_FORK \
| 1*SD_BALANCE_WAKE \
| 1*SD_WAKE_AFFINE \
+ | 1*SD_PREFER_LOCAL \
| 0*SD_SHARE_CPUPOWER \
| 1*SD_SHARE_PKG_RESOURCES \
| 0*SD_SERIALIZE \
@@ -161,6 +162,7 @@ int arch_update_cpu_topology(void);
| 1*SD_BALANCE_FORK \
| 1*SD_BALANCE_WAKE \
| 1*SD_WAKE_AFFINE \
+ | 1*SD_PREFER_LOCAL \
| 0*SD_SHARE_CPUPOWER \
| 0*SD_SHARE_PKG_RESOURCES \
| 0*SD_SERIALIZE \
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index 280892e..a37f311 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -1360,7 +1360,7 @@ static int select_task_rq_fair(struct task_struct *p, int sd_flag, int flags)
* If power savings logic is enabled for a domain, see if we
* are not overloaded, if so, don't balance wider.
*/
- if (tmp->flags & SD_POWERSAVINGS_BALANCE) {
+ if (tmp->flags & (SD_POWERSAVINGS_BALANCE|SD_PREFER_LOCAL)) {
unsigned long power = 0;
unsigned long nr_running = 0;
unsigned long capacity;
@@ -1373,7 +1373,10 @@ static int select_task_rq_fair(struct task_struct *p, int sd_flag, int flags)
capacity = DIV_ROUND_CLOSEST(power, SCHED_LOAD_SCALE);
- if (nr_running/2 < capacity)
+ if (tmp->flags & SD_POWERSAVINGS_BALANCE)
+ nr_running /= 2;
+
+ if (nr_running < capacity)
break;
}
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