linux/arch/x86
Alok Kataria 57779dc2b3 x86, tsc: Skip refined tsc calibration on systems with reliable TSC
While running the latest Linux as guest under VMware in highly
over-committed situations, we have seen cases when the refined TSC
algorithm fails to get a valid tsc_start value in
tsc_refine_calibration_work from multiple attempts. As a result the
kernel keeps on scheduling the tsc_irqwork task for later. Subsequently
after several attempts when it gets a valid start value it goes through
the refined calibration and either bails out or uses the new results.
Given that the kernel originally read the TSC frequency from the
platform, which is the best it can get, I don't think there is much
value in refining it.

So  for systems which get the TSC frequency from the platform we
should skip the refined tsc algorithm.

We can use the TSC_RELIABLE cpu cap flag to detect this, right now it is
set only on VMware and for Moorestown Penwell both of which have there
own TSC calibration methods.

Signed-off-by: Alok N Kataria <akataria@vmware.com>
Cc: John Stultz <johnstul@us.ibm.com>
Cc: Dirk Brandewie <dirk.brandewie@gmail.com>
Cc: Alan Cox <alan@linux.intel.com>
Cc: stable@kernel.org
[jstultz: Reworked to simply not schedule the refining work,
rather then scheduling the work and bombing out later]
Signed-off-by: John Stultz <john.stultz@linaro.org>
2012-03-15 18:23:11 -07:00
..
boot x86/boot-image: Don't leak phdrs in arch/x86/boot/compressed/misc.c::Parse_elf() 2012-01-26 11:30:29 +01:00
configs iommu: Rename the DMAR and INTR_REMAP config options 2011-09-21 10:22:03 +02:00
crypto crypto: serpent-sse2 - remove unneeded LRW/XTS #ifdefs 2011-12-20 15:20:08 +08:00
ia32 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/audit 2012-01-17 16:41:31 -08:00
include/asm x86: vdso: Use seqcount instead of seqlock 2012-03-15 18:17:58 -07:00
kernel x86, tsc: Skip refined tsc calibration on systems with reliable TSC 2012-03-15 18:23:11 -07:00
kvm KVM: do not #GP on perf MSR writes when vPMU is disabled 2012-02-01 11:44:46 +02:00
lguest lguest: Make sure interrupt is allocated ok by lguest_setup_irq 2012-01-12 15:44:47 +10:30
lib Merge branches 'sched-urgent-for-linus', 'perf-urgent-for-linus' and 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2012-01-19 14:53:06 -08:00
math-emu
mm Merge branches 'core-urgent-for-linus', 'perf-urgent-for-linus', 'sched-urgent-for-linus' and 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2012-02-02 11:11:13 -08:00
net net: bpf_jit: fix divide by 0 generation 2012-01-18 16:04:26 -05:00
oprofile Merge branch 'core' of git://amd64.org/linux/rric into perf/core 2011-11-15 11:05:18 +01:00
pci xen pvhvm: do not remap pirqs onto evtchns if !xen_have_vector_callback 2012-02-03 16:06:27 -05:00
platform x86/uv: Fix uninitialized spinlocks 2012-01-26 10:58:34 +01:00
power x86: Fix files explicitly requiring export.h for EXPORT_SYMBOL/THIS_MODULE 2011-10-31 19:30:35 -04:00
syscalls x86, syscall: Allow syscall offset to be symbolic 2011-11-18 17:01:19 -08:00
tools x86/tools: Add decoded instruction dump mode 2011-12-05 14:53:23 +01:00
um uml: fix compile for x86-64 2012-01-18 19:26:11 -08:00
vdso x86: vdso: Use seqcount instead of seqlock 2012-03-15 18:17:58 -07:00
video x86: fix up files really needing to include module.h 2011-10-31 19:30:36 -04:00
xen xen/smp: Fix CPU online/offline bug triggering a BUG: scheduling while atomic. 2012-02-03 16:05:42 -05:00
.gitignore x86/kprobes: Add arch/x86/tools/insn_sanity to .gitignore 2012-01-16 08:21:59 +01:00
Kbuild
Kconfig x86/numachip: Drop unnecessary conflict with EDAC 2012-01-26 11:03:03 +01:00
Kconfig.cpu mm,x86,um: move CMPXCHG_DOUBLE config option 2012-01-12 20:13:03 -08:00
Kconfig.debug Merge branch 'x86-platform-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2012-01-11 19:13:40 -08:00
Makefile x86: Generate system call tables and unistd_*.h from tables 2011-11-17 13:35:37 -08:00
Makefile.um um: take arch/um/sys-x86 to arch/x86/um 2011-11-02 14:15:05 +01:00
Makefile_32.cpu