linux/arch/x86
Dimitri Sivanich 14be1f7454 x86: Fix sched_clock_cpu for systems with unsynchronized TSC
On UV systems, the TSC is not synchronized across blades.  The
sched_clock_cpu() function is returning values that can go
backwards  (I've seen as much as 8 seconds) when switching
between cpus.

As each cpu comes up, early_init_intel() will currently set the
sched_clock_stable flag true.  When mark_tsc_unstable() runs, it
clears the flag, but this only occurs once (the first time a cpu
comes up whose TSC is not synchronized with cpu 0).  After this,
early_init_intel() will set the flag again as the next cpu comes
up.

Only set sched_clock_stable if tsc has not been marked unstable.

Signed-off-by: Dimitri Sivanich <sivanich@sgi.com>
Acked-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <20100301174815.GC8224@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-02 13:36:11 +01:00
..
boot Merge branch 'x86-setup-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2010-02-28 10:43:53 -08:00
configs
crypto Merge git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6 2009-12-01 15:16:22 +08:00
ia32 Merge branches 'core-ipi-for-linus', 'core-locking-for-linus', 'tracing-fixes-for-linus', 'x86-debug-for-linus', 'x86-doc-for-linus', 'x86-gpu-for-linus' and 'x86-rlimit-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2010-02-28 10:04:02 -08:00
include/asm Merge branch 'for-linus' of master.kernel.org:/home/rmk/linux-2.6-arm 2010-03-01 09:15:15 -08:00
kernel x86: Fix sched_clock_cpu for systems with unsynchronized TSC 2010-03-02 13:36:11 +01:00
kvm KVM: PIT: control word is write-only 2010-02-09 19:20:15 +02:00
lguest
lib Merge branch 'x86-rwsem-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2010-02-28 10:41:35 -08:00
math-emu
mm Merge branch 'x86-numa-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2010-02-28 10:39:36 -08:00
oprofile oprofile/x86: fix msr access to reserved counters 2010-02-26 15:28:16 +01:00
pci Merge branch 'x86-io-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2010-02-28 10:37:40 -08:00
power
tools x86: Remove trailing spaces in messages 2010-02-07 17:47:51 +01:00
vdso
video
xen x86: xen: 64-bit kernel RPL should be 0 2010-01-13 11:23:54 +01:00
Kbuild
Kconfig Merge branch 'tracing/core' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/random-tracing into tracing/core 2010-02-27 10:06:10 +01:00
Kconfig.cpu Merge branch 'x86-rwsem-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2010-02-28 10:41:35 -08:00
Kconfig.debug Merge branch 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-12-11 20:47:30 -08:00
Makefile x86-64: Allow fbdev primary video code 2010-02-16 21:22:26 -08:00
Makefile_32.cpu Merge branch 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-12-08 13:38:11 -08:00