Suresh Siddha aa68c0327e sched: Use group weight, idle cpu metrics to fix imbalances during idle ... Commit: aae6d3ddd8 upstream Currently we consider a sched domain to be well balanced when the imbalance is less than the domain's imablance_pct. As the number of cores and threads are increasing, current values of imbalance_pct (for example 25% for a NUMA domain) are not enough to detect imbalances like: a) On a WSM-EP system (two sockets, each having 6 cores and 12 logical threads), 24 cpu-hogging tasks get scheduled as 13 on one socket and 11 on another socket. Leading to an idle HT cpu. b) On a hypothetial 2 socket NHM-EX system (each socket having 8 cores and 16 logical threads), 16 cpu-hogging tasks can get scheduled as 9 on one socket and 7 on another socket. Leaving one core in a socket idle whereas in another socket we have a core having both its HT siblings busy. While this issue can be fixed by decreasing the domain's imbalance_pct (by making it a function of number of logical cpus in the domain), it can potentially cause more task migrations across sched groups in an overloaded case. Fix this by using imbalance_pct only during newly_idle and busy load balancing. And during idle load balancing, check if there is an imbalance in number of idle cpu's across the busiest and this sched_group or if the busiest group has more tasks than its weight that the idle cpu in this_group can pull. Reported-by: Nikhil Rao <ncrao@google.com> Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1284760952.2676.11.camel@sbsiddha-MOBL3.sc.intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Mike Galbraith <efault@gmx.de> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>		2011-02-17 15:37:28 -08:00
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acpi	ACPI: skip checking BM_STS if the BIOS doesn't ask for it	2010-08-02 10:21:24 -07:00
asm-generic	dma-mapping: fix dma_sync_single_range_*	2010-05-26 14:29:14 -07:00
crypto	Merge git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6	2009-09-11 09:38:37 -07:00
drm	drm/radeon: remove 0x4243 pci id	2011-02-17 15:37:16 -08:00
keys	RxRPC: Use uX/sX rather than uintX_t/intX_t types	2009-09-16 00:01:13 -07:00
linux	sched: Use group weight, idle cpu metrics to fix imbalances during idle	2011-02-17 15:37:28 -08:00
math-emu	math-emu: correct test for downshifting fraction in _FP_FROM_INT()	2010-08-02 10:20:44 -07:00
media	V4L/DVB (13019): video: initial support for ADV7180	2009-09-19 00:53:39 -03:00
mtd
net	sctp: Fix a race between ICMP protocol unreachable and connect()	2011-01-07 14:43:18 -08:00
pcmcia	PM / yenta: Split resume into early and late parts (rev. 4)	2009-11-03 10:54:58 +01:00
rdma	trivial: fix typo "to to" in multiple files	2009-09-21 15:14:55 +02:00
rxrpc
scsi	SCSI: fc-transport: Use packed modifier for fc_bsg_request structure.	2010-04-26 07:41:30 -07:00
sound	ALSA: emu10k1 - delay the PCM interrupts (add pcm_irq_delay parameter)	2010-08-26 16:41:34 -07:00
trace	tracing: Fix ftrace_event_call alignment for use with gcc 4.5	2010-05-12 14:57:14 -07:00
video	davinci-fb-frame-buffer-driver-for-ti-da8xx-omap-l1xx-v4	2009-09-23 07:39:51 -07:00
xen
Kbuild