Linus Torvalds 37407ea7f9 Revert "sched: Improve scalability via 'CPU buddies', which withstand random perturbations" ...

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>

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

gcov: disable CONSTRUCTORS for UML

2011-07-26 16:49:45 -07:00

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

Merge branch 'for-linus2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2012-01-08 12:19:57 -08:00

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

audit: remove AUDIT_SETUP_CONTEXT as it isn't used

2012-01-17 16:16:57 -05:00

auditfilter.c

audit: allow interfield comparison in audit rules

2012-01-17 16:17:01 -05:00

auditsc.c

seccomp: remove duplicated failure logging

2012-04-14 11:13:20 +10:00

backtracetest.c

…

bounds.c

memcg: remove direct page_cgroup-to-page pointer

2011-03-23 19:46:28 -07:00

capability.c

userns: Teach inode_capable to understand inodes whose uids map to other namespaces.

2012-05-15 14:59:24 -07:00

cgroup_freezer.c

cgroup: convert all non-memcg controllers to the new cftype interface

2012-04-01 12:09:55 -07:00

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

new helper: sigsuspend()

2012-05-21 23:52:30 -04:00

configs.c

kernel/configs.c: include MODULE_*() when CONFIG_IKCONFIG_PROC=n

2011-07-25 20:57:15 -07:00

cpu_pm.c

kernel/cpu_pm.c: fix various typos

2012-05-31 17:49:27 -07:00

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

Merge branch 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux

2011-11-06 19:44:47 -08:00

cred.c

keys: kill task_struct->replacement_session_keyring

2012-05-23 22:11:41 -04:00

delayacct.c

KVM: Steal time implementation

2011-07-14 12:59:14 +03:00

dma.c

Remove all #inclusions of asm/system.h

2012-03-28 18:30:03 +01:00

elfcore.c

elf coredump: add extended numbering support

2010-03-06 11:26:46 -08:00

exec_domain.c

sys_personality: remove the bogus checks in sys_personality()->__set_personality() path

2010-08-09 20:45:05 -07:00

exit.c

posix_types.h: Cleanup stale __NFDBITS and related definitions

2012-07-26 13:36:43 -07:00

extable.c

extable: Skip sorting if sorted at build time.

2012-04-19 15:06:55 -07:00

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

PM / Freezer: Remove references to TIF_FREEZE in comments

2012-03-04 23:08:54 +01:00

futex_compat.c

futex: Mark get_robust_list as deprecated

2012-03-29 11:37:17 +02:00

futex.c

futex: Forbid uaddr == uaddr2 in futex_wait_requeue_pi()

2012-07-24 16:02:57 +02:00

groups.c

userns: Convert in_group_p and in_egroup_p to use kgid_t

2012-05-03 03:29:33 -07:00

hrtimer.c

hrtimer: Update hrtimer base offsets each hrtimer_interrupt

2012-07-11 23:34:39 +02:00

hung_task.c

hung task debugging: Inject NMI when hung and going to panic

2012-04-25 12:39:25 +02:00

irq_work.c

irq_work: fix compile failure on tile from missing include

2012-04-13 13:15:16 -04:00

itimer.c

itimer: Use printk_once instead of WARN_ONCE

2012-04-10 11:00:30 +02:00

jump_label.c

static keys: Inline the static_key_enabled() function

2012-02-28 20:01:08 +01:00

kallsyms.c

vsprintf: fix %ps on non symbols when using kallsyms

2012-05-29 16:22:32 -07:00

kcmp.c

syscalls, x86: add __NR_kcmp syscall

2012-05-31 17:49:32 -07:00

Kconfig.freezer

…

Kconfig.hz

…

Kconfig.locks

locking/kconfig: Simplify INLINE_SPIN_UNLOCK usage

2012-03-23 13:18:57 +01:00

Kconfig.preempt

locking/kconfig: Simplify INLINE_SPIN_UNLOCK usage

2012-03-23 13:18:57 +01:00

kexec.c

kdump: append newline to the last lien of vmcoreinfo note

2012-07-30 17:25:20 -07:00

kfifo.c

[media] kernel:kfifo: export __kfifo_max_r symbol

2012-04-11 18:24:37 -03:00

kmod.c

kmod: avoid deadlock from recursive kmod call

2012-07-30 17:25:20 -07:00

kprobes.c

kprobes: return proper error code from register_kprobe()

2012-03-05 15:49:42 -08:00

ksysfs.c

kernel: ksysfs.c is implicitly using stat.h

2011-10-31 09:20:13 -04:00

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

kernel: Map most files to use export.h instead of module.h

2011-10-31 09:20:12 -04:00

lglock.c

brlocks/lglocks: turn into functions

2012-05-29 23:28:41 -04:00

lockdep_internals.h

lockdep: No need to disable preemption in debug atomic ops

2010-05-04 05:38:16 +02:00

lockdep_proc.c

kernel: Map most files to use export.h instead of module.h

2011-10-31 09:20:12 -04:00

lockdep_states.h

…

lockdep.c

lockdep: Add CPU-idle/offline warning to lockdep-RCU splat

2012-02-21 09:06:06 -08:00

Makefile

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2012-06-01 10:34:35 -07:00

module.c

Guard check in module loader against integer overflow

2012-05-23 22:28:53 +09:30

mutex-debug.c

kernel: Map most files to use export.h instead of module.h

2011-10-31 09:20:12 -04:00

mutex-debug.h

mutex: Use p->on_cpu for the adaptive spin

2011-04-14 08:52:33 +02:00

mutex.c

sched/rt: Use schedule_preempt_disabled()

2012-03-01 10:28:03 +01:00

mutex.h

mutex: Use p->on_cpu for the adaptive spin

2011-04-14 08:52:33 +02:00

notifier.c

kernel: Map most files to use export.h instead of module.h

2011-10-31 09:20:12 -04:00

nsproxy.c

kernel: Map most files to use export.h instead of module.h

2011-10-31 09:20:12 -04:00

padata.c

padata: Fix cpu hotplug

2012-03-29 19:52:46 +08:00

panic.c

panic: fix a possible deadlock in panic()

2012-07-30 17:25:13 -07:00

params.c

params: replace printk(KERN_<LVL>...) with pr_<lvl>(...)

2012-05-04 17:28:18 -07:00

pid_namespace.c

pidns: guarantee that the pidns init will be the last pidns process reaped

2012-06-20 14:39:36 -07:00

pid.c

mm: add a low limit to alloc_large_system_hash

2012-05-24 00:28:21 -04:00

posix-cpu-timers.c

[S390] cputime: add sparse checking and cleanup

2011-12-15 14:56:19 +01:00

posix-timers.c

kernel: Map most files to use export.h instead of module.h

2011-10-31 09:20:12 -04:00

printk.c

printk: Fix calculation of length used to discard records

2012-08-12 21:25:50 +03:00

profile.c

kernel: Map most files to use export.h instead of module.h

2011-10-31 09:20:12 -04:00

ptrace.c

userns: Convert ptrace, kill, set_priority permission checks to work with kuids and kgids

2012-05-03 03:28:51 -07:00

range.c

range: fix bogus misuse of module.h to get printk()

2011-10-31 09:20:11 -04:00

rcu.h

rcu: Allow nesting of rcu_idle_enter() and rcu_idle_exit()

2012-02-21 09:06:12 -08:00

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

splice: fix racy pipe->buffers uses

2012-06-13 21:16:42 +02:00

res_counter.c

rescounters: add res_counter_uncharge_until()

2012-05-29 16:22:27 -07:00

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: Simplify PI algorithm and make highest prio task get lock

2011-01-27 21:13:51 -05:00

rtmutex-debug.c

lockdep, rtmutex, bug: Show taint flags on error

2011-12-06 08:16:49 +01:00

rtmutex-debug.h

…

rtmutex-tester.c

rtmutex-tester: convert sysdev_class to a regular subsystem

2011-12-14 14:54:22 -08:00

rtmutex.c

Revert "rcu: Permit rt_mutex_unlock() with irqs disabled"

2011-12-11 10:33:18 -08:00

rtmutex.h

…

rwsem.c

Remove all #inclusions of asm/system.h

2012-03-28 18:30:03 +01:00

seccomp.c

seccomp: fix build warnings when there is no CONFIG_SECCOMP_FILTER

2012-04-18 12:24:52 +10:00

semaphore.c

semaphore: fix improper comment reference to mutex

2012-04-05 17:15:55 -07:00

signal.c

signal: make sure we don't get stopped with pending task_work

2012-07-22 23:57:54 +04:00

smp.c

smp: Remove ipi_call_lock[_irq]()/ipi_call_unlock[_irq]()

2012-06-05 17:27:14 +02:00

smpboot.c

smpboot, idle: Fix comment mismatch over idle_threads_init()

2012-05-24 22:58:08 +02:00

smpboot.h

smpboot: Remove leftover declaration

2012-06-11 15:07:52 +02:00

softirq.c

mm: allow PF_MEMALLOC from softirq context

2012-07-31 18:42:45 -07:00

spinlock.c

locking/kconfig: Simplify INLINE_SPIN_UNLOCK usage

2012-03-23 13:18:57 +01:00

srcu.c

rcu: Implement per-domain single-threaded call_srcu() state machine

2012-04-30 10:48:25 -07:00

stacktrace.c

kernel: Map most files to use export.h instead of module.h

2011-10-31 09:20:12 -04:00

stop_machine.c

Merge branch 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux

2011-11-06 19:44:47 -08:00

sys_ni.c

syscalls, x86: add __NR_kcmp syscall

2012-05-31 17:49:32 -07:00

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

kprobes: Fix selftest to clear flags field for reusing probes

2010-10-14 08:55:27 +02:00

time.c

time: Remove bogus comments

2012-03-15 18:17:55 -07:00

timeconst.pl

…

timer.c

alpha: take a bunch of syscalls into osf_sys.c

2012-08-19 08:41:19 -07:00

tracepoint.c

static keys: Introduce 'struct static_key', static_key_true()/false() and static_key_slow_[inc|dec]()

2012-02-24 10:05:59 +01:00

tsacct.c

[S390] cputime: add sparse checking and cleanup

2011-12-15 14:56:19 +01:00

uid16.c

userns: Convert setting and getting uid and gid system calls to use kuid and kgid

2012-05-03 03:28:41 -07:00

up.c

kernel: Map most files to use export.h instead of module.h

2011-10-31 09:20:12 -04:00

user_namespace.c

userns: Store uid and gid values in struct cred with kuid_t and kgid_t types

2012-05-03 03:28:38 -07:00

user-return-notifier.c

kernel: Map most files to use export.h instead of module.h

2011-10-31 09:20:12 -04:00

user.c

userns: Silence silly gcc warning.

2012-05-19 15:44:40 -06:00

utsname_sysctl.c

Merge branch 'modsplit-Oct31_2011' of git://git.kernel.org/pub/scm/linux/kernel/git/paulg/linux

2011-11-06 19:44:47 -08:00

utsname.c

userns: Use cred->user_ns instead of cred->user->user_ns

2012-04-07 16:55:51 -07:00

wait.c

lockdep/waitqueues: Add better annotation

2011-12-21 10:07:39 +01:00

watchdog.c

Revert "NMI watchdog: fix for lockup detector breakage on resume"

2012-08-08 20:49:45 +02:00

workqueue_sched.h

workqueue: implement concurrency managed dynamic worker pool

2010-06-29 10:07:14 +02:00

workqueue.c

workqueue: fix possible idle worker depletion across CPU hotplug

2012-09-10 10:05:54 -07:00