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5727347180
linux/arch/arm
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Will Deacon 5727347180 ARM: 7354/1: perf: limit sample_period to half max_period in non-sampling mode 
On ARM, the PMU does not stop counting after an overflow and therefore
IRQ latency affects the new counter value read by the kernel. This is
significant for non-sampling runs where it is possible for the new value
to overtake the previous one, causing the delta to be out by up to
max_period events.

Commit a737823d ("ARM: 6835/1: perf: ensure overflows aren't missed due
to IRQ latency") attempted to fix this problem by allowing interrupt
handlers to pass an overflow flag to the event update function, causing
the overflow calculation to assume that the counter passed through zero
when going from prev to new. Unfortunately, this doesn't work when
overflow occurs on the perf_task_tick path because we have the flag
cleared and end up computing a large negative delta.

This patch removes the overflow flag from armpmu_event_update and
instead limits the sample_period to half of the max_period for
non-sampling profiling runs.

Cc: <stable@vger.kernel.org>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2012-03-07 09:40:48 +00:00
..
boot Merge branch 'kbuild' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild 2012-01-16 14:34:54 -08:00
common ARM/PCI: Remove ARM's duplicate definition of 'pcibios_max_latency' 2012-02-21 09:35:32 +00:00
configs Consolidate i.MX 5 platforms to be under the new shared i.MX 3/5/6 tree. 2012-01-23 14:50:30 -08:00
include/asm ARM: 7354/1: perf: limit sample_period to half max_period in non-sampling mode 2012-03-07 09:40:48 +00:00
kernel ARM: 7354/1: perf: limit sample_period to half max_period in non-sampling mode 2012-03-07 09:40:48 +00:00
lib ARM: 7301/1: Rename the T() macro to TUSER() to avoid namespace conflicts 2012-01-25 11:07:40 +00:00
mach-at91 ARM: at91: Fix at91sam9g45 and at91cap9 reset 2012-01-20 17:22:50 +01:00
mach-bcmring ARM: bcmring: fix build failure in mach-bcmring/arch.c 2012-02-04 11:38:20 -08:00
mach-clps711x Merge branch 'depends/rmk/restart' into next/cleanup 2012-01-07 11:51:28 +00:00
mach-cns3xxx Merge branch 'linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci 2012-01-11 18:50:26 -08:00
mach-davinci ARM: davinci: update mdio bus name 2012-01-27 22:29:09 +05:30
mach-dove Merge branch 'linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci 2012-01-11 18:50:26 -08:00
mach-ebsa110 Merge branch 'depends/rmk/restart' into next/cleanup 2012-01-07 11:51:28 +00:00
mach-ep93xx Merge branch 'next' of git://git.infradead.org/users/vkoul/slave-dma 2012-01-17 18:40:24 -08:00
mach-exynos ARM: 7293/1: logical_cpu_map: decouple CPU mapping from SMP 2012-01-23 10:20:05 +00:00
mach-footbridge Merge branch 'linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci 2012-01-11 18:50:26 -08:00
mach-gemini ARM: big removal of now unused vmalloc.h files 2011-11-26 19:21:29 -05:00
mach-h720x Merge branch 'depends/rmk/restart' into next/cleanup 2012-01-07 11:51:28 +00:00
mach-highbank ARM: 7293/1: logical_cpu_map: decouple CPU mapping from SMP 2012-01-23 10:20:05 +00:00
mach-imx Merge branch 'fixes' of git://git.linaro.org/people/rmk/linux-arm 2012-01-28 13:27:10 -08:00
mach-integrator Merge branch 'linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci 2012-01-11 18:50:26 -08:00
mach-iop13xx Merge branch 'linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci 2012-01-11 18:50:26 -08:00
mach-iop32x Merge branch 'depends/rmk/restart' into next/cleanup 2012-01-07 11:51:28 +00:00
mach-iop33x Merge branch 'depends/rmk/restart' into next/cleanup 2012-01-07 11:51:28 +00:00
mach-ixp4xx Merge branch 'linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci 2012-01-11 18:50:26 -08:00
mach-ixp23xx Merge branch 'linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci 2012-01-11 18:50:26 -08:00
mach-ixp2000 Merge branch 'linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci 2012-01-11 18:50:26 -08:00
mach-kirkwood Merge branch 'linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci 2012-01-11 18:50:26 -08:00
mach-ks8695 Merge branch 'linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci 2012-01-11 18:50:26 -08:00
mach-l7200/include/mach
mach-lpc32xx Merge branch 'driver-core-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core 2012-01-07 12:03:30 -08:00
mach-mmp Merge branch 'samsung/driver' into next/drivers 2012-01-09 16:16:29 +00:00
mach-msm ARM: 7293/1: logical_cpu_map: decouple CPU mapping from SMP 2012-01-23 10:20:05 +00:00
mach-mv78xx0 Merge branch 'linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci 2012-01-11 18:50:26 -08:00
mach-mxs clock management changes for i.MX 2012-01-09 14:44:15 -08:00
mach-netx Merge branch 'depends/rmk/restart' into next/cleanup 2012-01-07 11:51:28 +00:00
mach-nomadik Merge branch 'depends/rmk/restart' into next/cleanup 2012-01-07 11:51:28 +00:00
mach-omap1 New feature development 2012-01-09 14:38:51 -08:00
mach-omap2 ARM: OMAP: fix voltage domain build errors with PM_OPP disabled 2012-02-21 09:36:34 +00:00
mach-orion5x Merge branch 'linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci 2012-01-11 18:50:26 -08:00
mach-picoxcell Merge branch 'picoxcell-fixes' of git://github.com/jamieiles/linux-2.6-ji into fixes 2012-01-16 22:45:42 -08:00
mach-pnx4008 Merge branch 'depends/rmk/restart' into next/cleanup 2012-01-07 11:51:28 +00:00
mach-prima2 Merge branch 'depends/rmk/restart' into next/cleanup 2012-01-07 11:51:28 +00:00
mach-pxa Revert "RTC: sa1100: support sa1100, pxa and mmp soc families" 2012-01-19 17:19:18 +00:00
mach-realview ARM: 7298/1: realview: fix mapping of MPCore private memory region 2012-01-25 09:24:36 +00:00
mach-rpc Merge branch 'depends/rmk/restart' into next/cleanup 2012-01-07 11:51:28 +00:00
mach-s3c64xx Merge branch 'samsung-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/kgene/linux-samsung into fixes 2012-01-16 22:46:19 -08:00
mach-s3c2410 Device tree conversions for samsung and tegra 2012-01-09 14:28:38 -08:00
mach-s3c2412 Device tree conversions for samsung and tegra 2012-01-09 14:28:38 -08:00
mach-s3c2416 Cleanups for the Samsung platforms 2012-01-09 14:30:28 -08:00
mach-s3c2440 Board-level changes 2012-01-09 14:37:41 -08:00
mach-s3c2443 Merge branch 'driver-core-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core 2012-01-07 12:03:30 -08:00
mach-s5p64x0 Driver specific changes 2012-01-09 14:39:22 -08:00
mach-s5pc100 Cleanups for the Samsung platforms 2012-01-09 14:30:28 -08:00
mach-s5pv210 Cleanups for the Samsung platforms 2012-01-09 14:30:28 -08:00
mach-sa1100 Merge branch 'sa11x0-mcp-fixes' into fixes 2012-01-26 21:06:54 +00:00
mach-shark Merge branch 'depends/rmk/restart' into next/cleanup 2012-01-07 11:51:28 +00:00
mach-shmobile Merge branch 'fixes' of git://git.infradead.org/users/vkoul/slave-dma 2012-02-04 10:54:26 -08:00
mach-spear3xx Merge branch 'depends/rmk/restart' into next/cleanup 2012-01-07 11:51:28 +00:00
mach-spear6xx Merge branch 'depends/rmk/restart' into next/cleanup 2012-01-07 11:51:28 +00:00
mach-tegra Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound 2012-01-12 08:00:30 -08:00
mach-u300 Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl 2012-01-10 10:19:57 -08:00
mach-ux500 ARM: 7346/1: errata: fix PL310 erratum #753970 workaround selection 2012-02-27 11:22:38 +00:00
mach-versatile Merge branch 'linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci 2012-01-11 18:50:26 -08:00
mach-vexpress ARM: 7346/1: errata: fix PL310 erratum #753970 workaround selection 2012-02-27 11:22:38 +00:00
mach-vt8500 ARM: big removal of now unused vmalloc.h files 2011-11-26 19:21:29 -05:00
mach-w90x900 Merge branch 'master' into fixes 2012-01-13 15:00:22 +00:00
mach-zynq Merge branch 'depends/rmk/restart' into next/cleanup 2012-01-07 11:51:28 +00:00
mm ARM: 7345/1: errata: update workaround for A9 erratum #743622 2012-02-27 11:22:08 +00:00
nwfpe ARM: 7207/1: Use generic ARM instruction set condition code checks for nwfpe. 2011-12-13 08:52:02 +00:00
oprofile oprofile, arm/sh: Fix oprofile_arch_exit() linkage issue 2011-12-23 11:58:34 +01:00
plat-iop Merge branch 'linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci 2012-01-11 18:50:26 -08:00
plat-mxc arm-soc fixes for 3.3-rc: 2012-01-28 13:21:54 -08:00
plat-nomadik Merge branch 'next' of git://git.infradead.org/users/vkoul/slave-dma 2012-01-17 18:40:24 -08:00
plat-omap ARM: Add arm_memblock_steal() to allocate memory away from the kernel 2012-01-13 15:02:35 +00:00
plat-orion New feature development 2012-01-09 14:38:51 -08:00
plat-pxa Merge branches 'drivers/macb-gem' and 'drivers/pxa-gpio' into next/drivers 2011-11-23 20:47:41 +00:00
plat-s3c24xx Merge branch 'master' into fixes 2012-01-13 15:00:22 +00:00
plat-s5p Merge branch 'driver-core-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core 2012-01-07 12:03:30 -08:00
plat-samsung ARM: fixes for ARM platforms 2012-01-17 18:55:56 -08:00
plat-spear ARM: 7348/1: arm/spear600: fix one-shot timer 2012-02-27 11:18:40 +00:00
plat-versatile ARM: 7293/1: logical_cpu_map: decouple CPU mapping from SMP 2012-01-23 10:20:05 +00:00
tools ARM: Update mach-types 2011-12-23 22:58:10 +00:00
vfp arm: remove several unnecessary module.h include instances 2011-10-31 19:30:48 -04:00
Kconfig ARM: 7345/1: errata: update workaround for A9 erratum #743622 2012-02-27 11:22:08 +00:00
Kconfig-nommu
Kconfig.debug Merge branches 'at91/gpio', 'at91/ioremap', 'drivers/macb-gem-cleanup' and 'msm/misc' into next/cleanup 2011-12-01 12:34:21 +00:00
Makefile Consolidate i.MX 5 platforms to be under the new shared i.MX 3/5/6 tree. 2012-01-23 14:50:30 -08:00