sched: Fix vmark regression on big machines (50b926e4) · Commits · 戴 / test

SD_PREFER_SIBLING is set at the CPU domain level if power saving isn't enabled, leading to many cache misses on large machines as we traverse looking for an idle shared cache to wake to. Change the enabler of select_idle_sibling() to SD_SHARE_PKG_RESOURCES, and enable same at the sibling domain level. Reported-by:

Lin Ming <ming.m.lin@intel.com> Signed-off-by:

Mike Galbraith <efault@gmx.de> Signed-off-by:

Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1262612696.15495.15.camel@marge.simson.net> Signed-off-by:

Ingo Molnar <mingo@elte.hu>

include/linux/topology.h

+1 −1

Original line number	Diff line number	Diff line
		@@ -99,7 +99,7 @@ int arch_update_cpu_topology(void);
		\| 1*SD_WAKE_AFFINE \
		\| 1*SD_SHARE_CPUPOWER \
		\| 0*SD_POWERSAVINGS_BALANCE \
		\| 0*SD_SHARE_PKG_RESOURCES \
		\| 1*SD_SHARE_PKG_RESOURCES \
		\| 0*SD_SERIALIZE \
		\| 0*SD_PREFER_SIBLING \
		, \

kernel/sched_fair.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -1508,7 +1508,7 @@ static int select_task_rq_fair(struct task_struct *p, int sd_flag, int wake_flag
		* If there's an idle sibling in this domain, make that
		* the wake_affine target instead of the current cpu.
		*/
		if (tmp->flags & SD_PREFER_SIBLING)
		if (tmp->flags & SD_SHARE_PKG_RESOURCES)
		target = select_idle_sibling(p, tmp, target);

		if (target >= 0) {

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