Revision 37407ea7f93864c2cfc03edf8f37872ec539ea2b authored by Linus Torvalds on 16 September 2012, 19:29:43 UTC, committed by Linus Torvalds on 16 September 2012, 19:29:43 UTC
This reverts commit 970e178985cadbca660feb02f4d2ee3a09f7fdda.
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 970e178985ca ("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>
1 parent 3f0c3c8
| File | Mode | Size |
|---|---|---|
| partitions | ||
| Kconfig | -rw-r--r-- | 3.3 KB |
| Kconfig.iosched | -rw-r--r-- | 1.6 KB |
| Makefile | -rw-r--r-- | 720 bytes |
| blk-cgroup.c | -rw-r--r-- | 23.7 KB |
| blk-cgroup.h | -rw-r--r-- | 13.6 KB |
| blk-core.c | -rw-r--r-- | 81.1 KB |
| blk-exec.c | -rw-r--r-- | 3.1 KB |
| blk-flush.c | -rw-r--r-- | 13.1 KB |
| blk-integrity.c | -rw-r--r-- | 11.5 KB |
| blk-ioc.c | -rw-r--r-- | 10.2 KB |
| blk-iopoll.c | -rw-r--r-- | 5.9 KB |
| blk-lib.c | -rw-r--r-- | 4.5 KB |
| blk-map.c | -rw-r--r-- | 8.2 KB |
| blk-merge.c | -rw-r--r-- | 13.2 KB |
| blk-settings.c | -rw-r--r-- | 25.7 KB |
| blk-softirq.c | -rw-r--r-- | 4.5 KB |
| blk-sysfs.c | -rw-r--r-- | 14.8 KB |
| blk-tag.c | -rw-r--r-- | 9.8 KB |
| blk-throttle.c | -rw-r--r-- | 31.0 KB |
| blk-timeout.c | -rw-r--r-- | 4.7 KB |
| blk.h | -rw-r--r-- | 7.1 KB |
| bsg-lib.c | -rw-r--r-- | 6.2 KB |
| bsg.c | -rw-r--r-- | 23.7 KB |
| cfq-iosched.c | -rw-r--r-- | 108.1 KB |
| compat_ioctl.c | -rw-r--r-- | 20.8 KB |
| deadline-iosched.c | -rw-r--r-- | 11.1 KB |
| elevator.c | -rw-r--r-- | 23.1 KB |
| genhd.c | -rw-r--r-- | 43.5 KB |
| ioctl.c | -rw-r--r-- | 10.2 KB |
| noop-iosched.c | -rw-r--r-- | 2.5 KB |
| partition-generic.c | -rw-r--r-- | 14.0 KB |
| scsi_ioctl.c | -rw-r--r-- | 19.6 KB |
Computing file changes ...
