linux/arch/x86
Suresh Siddha cd7240c0b9 x86, tsc, sched: Recompute cyc2ns_offset's during resume from sleep states
TSC's get reset after suspend/resume (even on cpu's with invariant TSC
which runs at a constant rate across ACPI P-, C- and T-states). And in
some systems BIOS seem to reinit TSC to arbitrary large value (still
sync'd across cpu's) during resume.

This leads to a scenario of scheduler rq->clock (sched_clock_cpu()) less
than rq->age_stamp (introduced in 2.6.32). This leads to a big value
returned by scale_rt_power() and the resulting big group power set by the
update_group_power() is causing improper load balancing between busy and
idle cpu's after suspend/resume.

This resulted in multi-threaded workloads (like kernel-compilation) go
slower after suspend/resume cycle on core i5 laptops.

Fix this by recomputing cyc2ns_offset's during resume, so that
sched_clock() continues from the point where it was left off during
suspend.

Reported-by: Florian Pritz <flo@xssn.at>
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: <stable@kernel.org> # [v2.6.32+]
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1282262618.2675.24.camel@sbsiddha-MOBL3.sc.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-08-20 14:59:02 +02:00
..
boot x86, setup: move isdigit.h to ctype.h, header files on top. 2010-08-02 21:07:20 -07:00
configs defconfig reduction 2010-08-14 22:26:53 +02:00
crypto Merge git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6 2010-05-03 11:28:58 +08:00
ia32 Mark arguments to certain syscalls as being const 2010-08-13 16:53:13 -07:00
include/asm x86, tsc, sched: Recompute cyc2ns_offset's during resume from sleep states 2010-08-20 14:59:02 +02:00
kernel x86, tsc, sched: Recompute cyc2ns_offset's during resume from sleep states 2010-08-20 14:59:02 +02:00
kvm x86, kvm: Remove cast obsoleted by set_64bit() prototype cleanup 2010-08-06 13:07:19 -07:00
lguest Merge branch 'ht-delete-2.6.35' into release 2010-05-28 16:20:35 -04:00
lib Merge branch 'x86/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2010-08-13 10:35:48 -07:00
math-emu x86, fpu: Unbreak FPU emulation 2010-05-10 13:37:16 -07:00
mm x86: don't send SIGBUS for kernel page faults 2010-08-13 09:49:20 -07:00
oprofile oprofile: add support for Intel processor model 30 2010-08-05 12:17:38 +02:00
pci x86/PCI: use for_each_pci_dev() 2010-07-30 09:47:33 -07:00
power x86, tsc, sched: Recompute cyc2ns_offset's during resume from sleep states 2010-08-20 14:59:02 +02:00
tools
vdso Merge branches 'x86-cleanups-for-linus', 'x86-vmware-for-linus', 'x86-mtrr-for-linus', 'x86-apic-for-linus', 'x86-fpu-for-linus' and 'x86-vdso-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2010-08-06 16:22:59 -07:00
video
xen Merge branch 'stable/xen-swiotlb-0.8.6' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen 2010-08-12 09:09:41 -07:00
.gitignore
Kbuild
Kconfig Merge branch 'x86-olpc-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2010-08-06 16:24:34 -07:00
Kconfig.cpu Merge branch 'x86-fpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2010-05-18 08:58:16 -07:00
Kconfig.debug Merge branch 'x86-cleanups-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2010-05-18 08:40:21 -07:00
Makefile x86: Use .cfi_sections for assembly code 2010-05-13 22:15:18 -07:00
Makefile_32.cpu