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
..
debug	kernel/debug: Make use of KGDB_REASON_NMI	2012-07-31 08:16:43 -05:00
events	perf/hwpb: Invoke __perf_event_disable() if interrupts are already disabled	2012-09-04 17:29:53 +02:00
gcov
irq	Merge branch 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip	2012-08-03 10:56:44 -07:00
power	Revert "NMI watchdog: fix for lockup detector breakage on resume"	2012-08-08 20:49:45 +02:00
sched	Revert "sched: Improve scalability via 'CPU buddies', which withstand random perturbations"	2012-09-16 12:29:43 -07:00
time	sched: Add missing call to calc_load_exit_idle()	2012-09-04 14:30:29 +02:00
trace	tracing/syscalls: Fix perf syscall tracing when syscall_nr == -1	2012-08-17 15:19:46 -04:00
.gitignore
acct.c
async.c	[SCSI] async: make async_synchronize_full() flush all work regardless of domain	2012-07-20 09:07:37 +01:00
audit_tree.c	audit: clean up refcounting in audit-tree	2012-08-15 12:55:22 +02:00
audit_watch.c	get rid of kern_path_parent()	2012-07-14 16:35:02 +04:00
audit.c	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2012-08-01 10:26:23 -07:00
audit.h
auditfilter.c
auditsc.c
backtracetest.c
bounds.c
capability.c
cgroup_freezer.c
cgroup.c	Merge branch 'for-3.6' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup	2012-07-24 17:47:44 -07:00
compat.c
configs.c
cpu_pm.c
cpu.c	mm/hotplug: correctly setup fallback zonelists when creating new pgdat	2012-07-31 18:42:44 -07:00
cpuset.c	cpusets: Remove/update outdated comments	2012-07-24 13:53:28 +02:00
crash_dump.c
cred.c
delayacct.c
dma.c
elfcore.c
exec_domain.c
exit.c	posix_types.h: Cleanup stale __NFDBITS and related definitions	2012-07-26 13:36:43 -07:00
extable.c
fork.c	uprobes: Fix mmap_region()'s mm->mm_rb corruption if uprobe_mmap() fails	2012-08-21 11:48:12 +02:00
freezer.c
futex_compat.c
futex.c	futex: Forbid uaddr == uaddr2 in futex_wait_requeue_pi()	2012-07-24 16:02:57 +02:00
groups.c
hrtimer.c	hrtimer: Update hrtimer base offsets each hrtimer_interrupt	2012-07-11 23:34:39 +02:00
hung_task.c
irq_work.c
itimer.c
jump_label.c
kallsyms.c
kcmp.c
Kconfig.freezer
Kconfig.hz
Kconfig.locks
Kconfig.preempt
kexec.c	kdump: append newline to the last lien of vmcoreinfo note	2012-07-30 17:25:20 -07:00
kfifo.c
kmod.c	kmod: avoid deadlock from recursive kmod call	2012-07-30 17:25:20 -07:00
kprobes.c
ksysfs.c
kthread.c	kthread_worker: reimplement flush_kthread_work() to allow freeing the work item being executed	2012-07-22 10:15:28 -07:00
latencytop.c
lglock.c
lockdep_internals.h
lockdep_proc.c
lockdep_states.h
lockdep.c
Makefile
module.c
mutex-debug.c
mutex-debug.h
mutex.c
mutex.h
notifier.c
nsproxy.c
padata.c
panic.c	panic: fix a possible deadlock in panic()	2012-07-30 17:25:13 -07:00
params.c
pid_namespace.c
pid.c
posix-cpu-timers.c
posix-timers.c
printk.c	printk: Fix calculation of length used to discard records	2012-08-12 21:25:50 +03:00
profile.c
ptrace.c
range.c
rcu.h
rcupdate.c	rcu: Consolidate tree/tiny __rcu_read_{,un}lock() implementations	2012-07-02 12:34:23 -07:00
rcutiny_plugin.h	rcu: Fix code-style issues involving "else"	2012-07-06 06:01:48 -07:00
rcutiny.c	rcu: Fix rcu_is_cpu_idle() #ifdef in TINY_RCU	2012-07-02 12:34:25 -07:00
rcutorture.c	rcu: Fix broken strings in RCU's source code.	2012-07-06 06:01:49 -07:00
rcutree_plugin.h	rcu: Fix code-style issues involving "else"	2012-07-06 06:01:48 -07:00
rcutree_trace.c	rcu: Fix broken strings in RCU's source code.	2012-07-06 06:01:49 -07:00
rcutree.c	rcu: Fix code-style issues involving "else"	2012-07-06 06:01:48 -07:00
rcutree.h	Merge branches 'bigrtm.2012.07.04a', 'doctorture.2012.07.02a', 'fixes.2012.07.06a' and 'fnh.2012.07.02a' into HEAD	2012-07-06 05:59:30 -07:00
relay.c
res_counter.c
resource.c	resource: make sure requested range is included in the root range	2012-07-30 17:25:21 -07:00
rtmutex_common.h
rtmutex-debug.c
rtmutex-debug.h
rtmutex-tester.c
rtmutex.c
rtmutex.h
rwsem.c
seccomp.c
semaphore.c
signal.c	signal: make sure we don't get stopped with pending task_work	2012-07-22 23:57:54 +04:00
smp.c
smpboot.c
smpboot.h
softirq.c	mm: allow PF_MEMALLOC from softirq context	2012-07-31 18:42:45 -07:00
spinlock.c
srcu.c
stacktrace.c
stop_machine.c
sys_ni.c
sys.c	kernel/sys.c: avoid argv_free(NULL)	2012-07-30 17:25:13 -07:00
sysctl_binary.c	mm: prepare for removal of obsolete /proc/sys/vm/nr_pdflush_threads	2012-07-31 18:42:40 -07:00
sysctl.c	Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs	2012-08-01 10:26:23 -07:00
task_work.c	task_work: add a scheduling point in task_work_run()	2012-08-21 09:11:44 -07:00
taskstats.c	taskstats: check nla_reserve() return	2012-07-30 17:25:21 -07:00
test_kprobes.c
time.c
timeconst.pl
timer.c	alpha: take a bunch of syscalls into osf_sys.c	2012-08-19 08:41:19 -07:00
tracepoint.c
tsacct.c
uid16.c
up.c
user_namespace.c
user-return-notifier.c
user.c
utsname_sysctl.c
utsname.c
wait.c
watchdog.c	Revert "NMI watchdog: fix for lockup detector breakage on resume"	2012-08-08 20:49:45 +02:00
workqueue_sched.h
workqueue.c	workqueue: fix possible idle worker depletion across CPU hotplug	2012-09-10 10:05:54 -07:00