linux_dsm_epyc7002/arch/x86
Robert Richter ba52078e19 oprofile/x86: implement randomization for IBS periodic op counter
IBS selects an op (execution operation) for sampling by counting
either cycles or dispatched ops. Better statistical samples can be
produced by adding a software generated random offset to the periodic
op counter value with each sample.

This patch adds software randomization to the IBS periodic op
counter. The lower 12 bits of the 20 bit counter are
randomized. IbsOpCurCnt is initialized with a 12 bit random value.

There is a work around if the hw can not write to IbsOpCurCnt. Then
the lower 8 bits of the 16 bit IbsOpMaxCnt [15:0] value are randomized
in the range of -128 to +127 by adding/subtracting an offset to the
maximum count (IbsOpMaxCnt).

The linear feedback shift register (LFSR) algorithm is used for
pseudo-random number generation to have low impact to the memory
system.

Signed-off-by: Robert Richter <robert.richter@amd.com>
2010-02-26 15:14:02 +01:00
..
boot x86: add support for LZO-compressed kernels 2010-01-11 09:34:05 -08:00
configs tracing: Rename FTRACE_SYSCALLS for tracepoints 2009-08-26 00:17:35 +02:00
crypto Merge git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6 2009-12-01 15:16:22 +08:00
ia32 x86: get rid of the insane TIF_ABI_PENDING bit 2010-01-29 08:22:01 -08:00
include/asm x86-32: Make AT_VECTOR_SIZE_ARCH=2 2010-02-09 16:05:08 -08:00
kernel Merge branch 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2010-02-11 14:01:10 -08:00
kvm KVM: PIT: control word is write-only 2010-02-09 19:20:15 +02:00
lguest lguest: move panic notifier registration to its expected place. 2009-09-23 22:26:44 +09:30
lib Merge branch 'iommu/fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/linux-2.6-iommu into x86/urgent 2009-12-28 09:23:13 +01:00
math-emu
mm Merge branch 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2010-02-11 14:01:10 -08:00
oprofile oprofile/x86: implement randomization for IBS periodic op counter 2010-02-26 15:14:02 +01:00
pci x86/PCI: remove IOH range fetching 2010-01-28 08:24:11 -08:00
power hw-breakpoints: Rewrite the hw-breakpoints layer on top of perf events 2009-11-08 15:34:42 +01:00
tools Merge branch 'iommu/fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/linux-2.6-iommu into x86/urgent 2009-12-28 09:23:13 +01:00
vdso sysctl x86: Remove dead binary sysctl support 2009-11-12 02:05:04 -08:00
video
xen x86: xen: 64-bit kernel RPL should be 0 2010-01-13 11:23:54 +01:00
Kbuild
Kconfig x86: Remove "x86 CPU features in debugfs" (CONFIG_X86_CPU_DEBUG) 2010-01-23 18:27:47 -08:00
Kconfig.cpu Revert "x86: Side-step lguest problem by only building cmpxchg8b_emu for pre-Pentium" 2010-01-05 16:01:35 -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 Merge branch 'perf/core' into perf/probes 2009-11-17 10:17:47 +01:00
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