* [patch] sched: fix sd_parent_degenerate on non-numa smp machine
@ 2008-12-08 2:47 Ken Chen
2008-12-08 12:53 ` Ingo Molnar
0 siblings, 1 reply; 2+ messages in thread
From: Ken Chen @ 2008-12-08 2:47 UTC (permalink / raw)
To: Ingo Molnar, Peter Zijlstra; +Cc: Linux Kernel Mailing List
The addition of SD_SERIALIZE flag added to SD_NODE_INIT prevented top level
dummy numa sched_domain to be properly degenerated on non-numa smp machine.
The reason is that in sd_parent_degenerate(), it found that the child and
parent does not have comon sched_domain flags due to SD_SERIALIZE. However,
for non-numa smp box, the top level is a dummy with a single sched_group.
Filter out SD_SERIALIZE if it is on non-numa machine to properly degenerate
top level node sched_domain. this will cut back some of the sd domain walk
in the load balancer code.
Signed-off-by: Ken Chen <kenchen@google.com>
diff --git a/kernel/sched.c b/kernel/sched.c
index b7480fb..6beae36 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -6814,6 +6814,8 @@ sd_parent_degenerate
SD_BALANCE_EXEC |
SD_SHARE_CPUPOWER |
SD_SHARE_PKG_RESOURCES);
+ if (nr_node_ids == 1)
+ pflags &= ~SD_SERIALIZE;
}
if (~cflags & pflags)
return 0;
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [patch] sched: fix sd_parent_degenerate on non-numa smp machine
2008-12-08 2:47 [patch] sched: fix sd_parent_degenerate on non-numa smp machine Ken Chen
@ 2008-12-08 12:53 ` Ingo Molnar
0 siblings, 0 replies; 2+ messages in thread
From: Ingo Molnar @ 2008-12-08 12:53 UTC (permalink / raw)
To: Ken Chen; +Cc: Peter Zijlstra, Linux Kernel Mailing List
* Ken Chen <kenchen@google.com> wrote:
> The addition of SD_SERIALIZE flag added to SD_NODE_INIT prevented top level
> dummy numa sched_domain to be properly degenerated on non-numa smp machine.
> The reason is that in sd_parent_degenerate(), it found that the child and
> parent does not have comon sched_domain flags due to SD_SERIALIZE. However,
> for non-numa smp box, the top level is a dummy with a single sched_group.
>
> Filter out SD_SERIALIZE if it is on non-numa machine to properly degenerate
> top level node sched_domain. this will cut back some of the sd domain walk
> in the load balancer code.
>
> Signed-off-by: Ken Chen <kenchen@google.com>
applied to tip/sched/core, thanks Ken!
Ingo
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2008-12-08 12:53 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2008-12-08 2:47 [patch] sched: fix sd_parent_degenerate on non-numa smp machine Ken Chen
2008-12-08 12:53 ` Ingo Molnar
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.