Linus Torvalds 37407ea7f9 Revert "sched: Improve scalability via 'CPU buddies', which withstand random perturbations" ... This reverts commit 970e178985. Nikolay Ulyanitsky reported thatthe 3.6-rc5 kernel has a 15-20% performance drop on PostgreSQL 9.2 on his machine (running "pgbench"). Borislav Petkov was able to reproduce this, and bisected it to this commit 970e178985 ("sched: Improve scalability via 'CPU buddies' ...") apparently because the new single-idle-buddy model simply doesn't find idle CPU's to reschedule on aggressively enough. Mike Galbraith suspects that it is likely due to the user-mode spinlocks in PostgreSQL not reacting well to preemption, but we don't really know the details - I'll just revert the commit for now. There are hopefully other approaches to improve scheduler scalability without it causing these kinds of downsides. Reported-by: Nikolay Ulyanitsky <lystor@gmail.com> Bisected-by: Borislav Petkov <bp@alien8.de> Acked-by: Mike Galbraith <efault@gmx.de> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>		2012-09-16 12:29:43 -07:00
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acpi	Merge branches 'delete-gts-bfs', 'misc', 'novell-bugzilla-757888-numa' and 'osc-pcie' into base	2012-08-03 00:31:23 -04:00
asm-generic	mutex: Place lock in contended state after fastpath_lock failure	2012-08-13 18:46:54 +02:00
crypto
drm	drm: Drop the NV12M and YUV420M formats	2012-09-13 12:38:10 +09:00
keys
linux	Revert "sched: Improve scalability via 'CPU buddies', which withstand random perturbations"	2012-09-16 12:29:43 -07:00
math-emu
media	[media] v4l2: add core support for the new VIDIOC_ENUM_FREQ_BANDS ioctl	2012-07-30 20:23:05 -03:00
memory
misc
mtd
net	Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/linville/wireless into for-davem	2012-09-07 14:38:50 -04:00
pcmcia
ras
rdma	Merge branches 'cma', 'cxgb4', 'misc', 'mlx4-sriov', 'mlx-cleanups', 'ocrdma' and 'qib' into for-linus	2012-07-22 23:26:17 -07:00
rxrpc
scsi	Merge branch 'master' [vanilla Linus master] into libata-dev.git/upstream	2012-07-25 15:58:48 -04:00
sound	ASoC: Additional updates for 3.6	2012-08-20 21:26:04 +02:00
target	target: Remove unused se_cmd.cmd_spdtl	2012-08-21 14:27:35 -07:00
trace	Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2012-08-03 10:57:20 -07:00
video	video: da8xx-fb: configure FIFO threshold to reduce underflow errors	2012-07-29 01:11:09 +00:00
xen	Revert "xen PVonHVM: move shared_info to MMIO before kexec"	2012-08-16 13:05:25 -04:00
Kbuild