lwn.git/arch/powerpc/kernel/perf_event.c, branch v3.4.11

powerpc/perf: Move perf core & PMU code into a subdirectory

2012-02-22T23:50:04+00:00

The perf code has grown a lot since it started, and is big enough to warrant its own subdirectory. For reference it's ~60% bigger than the oprofile code. It declutters the kernel directory, makes it simpler to grep for "just perf stuff", and allows us to shorten some filenames. While we're at it, make it more obvious that we have two implementations of the core perf logic. One for (roughly) Book3S CPUs, which was the original implementation, and the other for Freescale embedded CPUs. Signed-off-by: Michael Ellerman Signed-off-by: Benjamin Herrenschmidt

powerpc/perf: power_pmu_start restores incorrect values, breaking frequency events

2012-02-16T05:24:35+00:00

perf on POWER stopped working after commit e050e3f0a71b (perf: Fix broken interrupt rate throttling). That patch exposed a bug in the POWER perf_events code. Since the PMCs count upwards and take an exception when the top bit is set, we want to write 0x80000000 - left in power_pmu_start. We were instead programming in left which effectively disables the counter until we eventually hit 0x80000000. This could take seconds or longer. With the patch applied I get the expected number of samples: SAMPLE events: 9948 Signed-off-by: Anton Blanchard Acked-by: Paul Mackerras Signed-off-by: Benjamin Herrenschmidt Cc:

Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc

2011-07-26T05:59:39+00:00

* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc: (99 commits) drivers/virt: add missing linux/interrupt.h to fsl_hypervisor.c powerpc/85xx: fix mpic configuration in CAMP mode powerpc: Copy back TIF flags on return from softirq stack powerpc/64: Make server perfmon only built on ppc64 server devices powerpc/pseries: Fix hvc_vio.c build due to recent changes powerpc: Exporting boot_cpuid_phys powerpc: Add CFAR to oops output hvc_console: Add kdb support powerpc/pseries: Fix hvterm_raw_get_chars to accept < 16 chars, fixing xmon powerpc/irq: Quieten irq mapping printks powerpc: Enable lockup and hung task detectors in pseries and ppc64 defeconfigs powerpc: Add mpt2sas driver to pseries and ppc64 defconfig powerpc: Disable IRQs off tracer in ppc64 defconfig powerpc: Sync pseries and ppc64 defconfigs powerpc/pseries/hvconsole: Fix dropped console output hvc_console: Improve tty/console put_chars handling powerpc/kdump: Fix timeout in crash_kexec_wait_realmode powerpc/mm: Fix output of total_ram. powerpc/cpufreq: Add cpufreq driver for Momentum Maple boards powerpc: Correct annotations of pmu registration functions ... Fix up trivial Kconfig/Makefile conflicts in arch/powerpc, drivers, and drivers/cpufreq

powerpc: Correct annotations of pmu registration functions

2011-07-19T05:12:40+00:00

This fixes the following warning: WARNING: arch/powerpc/kernel/built-in.o(.text+0x29768): Section mismatch in reference from the function .register_power_pmu() to the function .cpuinit.text:.power_pmu_notifier() The function .register_power_pmu() references the function __cpuinit .power_pmu_notifier(). This is often because .register_power_pmu lacks a __cpuinit annotation or the annotation of .power_pmu_notifier is wrong. Signed-off-by: Dmitry Eremin-Solenikov Signed-off-by: Benjamin Herrenschmidt

perf: Remove the nmi parameter from the swevent and overflow interface

2011-07-01T09:06:35+00:00

The nmi parameter indicated if we could do wakeups from the current context, if not, we would set some state and self-IPI and let the resulting interrupt do the wakeup. For the various event classes: - hardware: nmi=0; PMI is in fact an NMI or we run irq_work_run from the PMI-tail (ARM etc.) - tracepoint: nmi=0; since tracepoint could be from NMI context. - software: nmi=[0,1]; some, like the schedule thing cannot perform wakeups, and hence need 0. As one can see, there is very little nmi=1 usage, and the down-side of not using it is that on some platforms some software events can have a jiffy delay in wakeup (when arch_irq_work_raise isn't implemented). The up-side however is that we can remove the nmi parameter and save a bunch of conditionals in fast paths. Signed-off-by: Peter Zijlstra Cc: Michael Cree Cc: Will Deacon Cc: Deng-Cheng Zhu Cc: Anton Blanchard Cc: Eric B Munson Cc: Heiko Carstens Cc: Paul Mundt Cc: David S. Miller Cc: Frederic Weisbecker Cc: Jason Wessel Cc: Don Zickus Link: http://lkml.kernel.org/n/tip-agjev8eu666tvknpb3iaj0fg@git.kernel.org Signed-off-by: Ingo Molnar

powerpc/perf_event: Skip updating kernel counters if register value shrinks

2011-04-18T03:08:23+00:00

Because of speculative event roll back, it is possible for some event coutners to decrease between reads on POWER7. This causes a problem with the way that counters are updated. Delta calues are calculated in a 64 bit value and the top 32 bits are masked. If the register value has decreased, this leaves us with a very large positive value added to the kernel counters. This patch protects against this by skipping the update if the delta would be negative. This can lead to a lack of precision in the coutner values, but from my testing the value is typcially fewer than 10 samples at a time. Signed-off-by: Eric B Munson Cc: stable@kernel.org Signed-off-by: Benjamin Herrenschmidt

Fix common misspellings

2011-03-31T14:26:23+00:00

Fixes generated by 'codespell' and manually reviewed. Signed-off-by: Lucas De Marchi

perf, powerpc: Handle events that raise an exception without overflowing

2011-03-16T13:04:13+00:00

Events on POWER7 can roll back if a speculative event doesn't eventually complete. Unfortunately in some rare cases they will raise a performance monitor exception. We need to catch this to ensure we reset the PMC. In all cases the PMC will be 256 or less cycles from overflow. Signed-off-by: Anton Blanchard Signed-off-by: Peter Zijlstra Cc: # as far back as it applies cleanly LKML-Reference: <20110309143842.6c22845e@kryten> Signed-off-by: Ingo Molnar

powerpc: perf: Fix frequency calculation for overflowing counters

2011-01-17T10:43:02+00:00

When profiling a benchmark that is almost 100% userspace, I noticed some wildly inaccurate profiles that showed almost all time spent in the kernel. Closer examination shows we were programming a tiny number of cycles into the PMU after each overflow (about ~200 away from the next overflow). This gets us stuck in a loop which we eventually break out of by throttling the PMU (there are regular throttle/unthrottle events in the log). It looks like we aren't setting event->hw.last_period to something same and the frequency to period calculations in perf are going haywire. With the following patch we find the correct period after a few interrupts and stay there. I also see no more throttle events. Signed-off-by: Anton Blanchard Acked-by: Benjamin Herrenschmidt Cc: linuxppc-dev@lists.ozlabs.org Cc: Paul Mackerras Cc: Peter Zijlstra Cc: Arnaldo Carvalho de Melo LKML-Reference: <20110117161742.5feb3761@kryten> Signed-off-by: Ingo Molnar

perf: Dynamic pmu types

2010-12-16T10:36:43+00:00

Extend the perf_pmu_register() interface to allow for named and dynamic pmu types. Because we need to support the existing static types we cannot use dynamic types for everything, hence provide a type argument. If we want to enumerate the PMUs they need a name, provide one. Signed-off-by: Peter Zijlstra LKML-Reference: <20101117222056.259707703@chello.nl> Signed-off-by: Ingo Molnar