From 721a669b7225edeeb0ca8e2bf71b83882326a71b Mon Sep 17 00:00:00 2001 From: Soeren Sandmann Date: Tue, 15 Sep 2009 14:33:08 +0200 Subject: [PATCH 1/4] perf events: Fix swevent hrtimer sampling by keeping track of remaining time when enabling/disabling swevent hrtimers MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Make the hrtimer based events work for sysprof. Whenever a swevent is scheduled out, the hrtimer is canceled. When it is scheduled back in, the timer is restarted. This happens every scheduler tick, which means the timer never expired because it was getting repeatedly restarted over and over with the same period. To fix that, save the remaining time when disabling; when reenabling, use that saved time as the period instead of the user-specified sampling period. Also, move the starting and stopping of the hrtimers to helper functions instead of duplicating the code. Signed-off-by: Søren Sandmann Pedersen LKML-Reference: Signed-off-by: Ingo Molnar --- include/linux/perf_event.h | 4 +-- kernel/perf_event.c | 61 +++++++++++++++++++++++++------------- 2 files changed, 43 insertions(+), 22 deletions(-) diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index 2e6d95f97419..9e7012689a84 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -471,8 +471,8 @@ struct hw_perf_event { unsigned long event_base; int idx; }; - union { /* software */ - atomic64_t count; + struct { /* software */ + s64 remaining; struct hrtimer hrtimer; }; }; diff --git a/kernel/perf_event.c b/kernel/perf_event.c index afb7ef3dbc44..33ff019f9aa6 100644 --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -3969,6 +3969,42 @@ static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer) return ret; } +static void perf_swevent_start_hrtimer(struct perf_event *event) +{ + struct hw_perf_event *hwc = &event->hw; + + hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); + hwc->hrtimer.function = perf_swevent_hrtimer; + if (hwc->sample_period) { + u64 period; + + if (hwc->remaining) { + if (hwc->remaining < 0) + period = 10000; + else + period = hwc->remaining; + hwc->remaining = 0; + } else { + period = max_t(u64, 10000, hwc->sample_period); + } + __hrtimer_start_range_ns(&hwc->hrtimer, + ns_to_ktime(period), 0, + HRTIMER_MODE_REL, 0); + } +} + +static void perf_swevent_cancel_hrtimer(struct perf_event *event) +{ + struct hw_perf_event *hwc = &event->hw; + + if (hwc->sample_period) { + ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer); + hwc->remaining = ktime_to_ns(remaining); + + hrtimer_cancel(&hwc->hrtimer); + } +} + /* * Software event: cpu wall time clock */ @@ -3991,22 +4027,14 @@ static int cpu_clock_perf_event_enable(struct perf_event *event) int cpu = raw_smp_processor_id(); atomic64_set(&hwc->prev_count, cpu_clock(cpu)); - hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); - hwc->hrtimer.function = perf_swevent_hrtimer; - if (hwc->sample_period) { - u64 period = max_t(u64, 10000, hwc->sample_period); - __hrtimer_start_range_ns(&hwc->hrtimer, - ns_to_ktime(period), 0, - HRTIMER_MODE_REL, 0); - } + perf_swevent_start_hrtimer(event); return 0; } static void cpu_clock_perf_event_disable(struct perf_event *event) { - if (event->hw.sample_period) - hrtimer_cancel(&event->hw.hrtimer); + perf_swevent_cancel_hrtimer(event); cpu_clock_perf_event_update(event); } @@ -4043,22 +4071,15 @@ static int task_clock_perf_event_enable(struct perf_event *event) now = event->ctx->time; atomic64_set(&hwc->prev_count, now); - hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); - hwc->hrtimer.function = perf_swevent_hrtimer; - if (hwc->sample_period) { - u64 period = max_t(u64, 10000, hwc->sample_period); - __hrtimer_start_range_ns(&hwc->hrtimer, - ns_to_ktime(period), 0, - HRTIMER_MODE_REL, 0); - } + + perf_swevent_start_hrtimer(event); return 0; } static void task_clock_perf_event_disable(struct perf_event *event) { - if (event->hw.sample_period) - hrtimer_cancel(&event->hw.hrtimer); + perf_swevent_cancel_hrtimer(event); task_clock_perf_event_update(event, event->ctx->time); } From 54f4407608c59712a8f5ec1e10dfac40bef5a2e7 Mon Sep 17 00:00:00 2001 From: Soeren Sandmann Date: Thu, 22 Oct 2009 18:34:08 +0200 Subject: [PATCH 2/4] perf events: Don't generate events for the idle task when exclude_idle is set MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Getting samples for the idle task is often not interesting, so don't generate them when exclude_idle is set for the event in question. Signed-off-by: Søren Sandmann Pedersen Cc: Peter Zijlstra Cc: Mike Galbraith Cc: Paul Mackerras Cc: Arnaldo Carvalho de Melo Cc: Frederic Weisbecker Cc: Steven Rostedt LKML-Reference: Signed-off-by: Ingo Molnar --- kernel/perf_event.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/kernel/perf_event.c b/kernel/perf_event.c index 33ff019f9aa6..7f29643c8985 100644 --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -3959,8 +3959,9 @@ static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer) regs = task_pt_regs(current); if (regs) { - if (perf_event_overflow(event, 0, &data, regs)) - ret = HRTIMER_NORESTART; + if (!(event->attr.exclude_idle && current->pid == 0)) + if (perf_event_overflow(event, 0, &data, regs)) + ret = HRTIMER_NORESTART; } period = max_t(u64, 10000, event->hw.sample_period); From 84087126d50400789b44459cfc45721778e6ebb0 Mon Sep 17 00:00:00 2001 From: Marti Raudsepp Date: Sat, 24 Oct 2009 19:10:36 +0300 Subject: [PATCH 3/4] perf tools: Fix compatibility with libelf 0.8 and autodetect The Makefile now automatically defines LIBELF_NO_MMAP when libelf 0.8.x is detected. libelf 0.8 is still maintained and some distributions such as Arch Linux use it instead of elfutils. Signed-off-by: Marti Raudsepp Cc: Lucas De Marchi Cc: Peter Zijlstra Cc: Paul Mackerras Cc: Frederic Weisbecker Cc: Arnaldo Carvalho de Melo Cc: Arjan van de Ven Cc: Mike Galbraith LKML-Reference: <1256400636.3007.16.camel@newn> Signed-off-by: Ingo Molnar --- tools/perf/Makefile | 6 +++++- tools/perf/util/symbol.c | 6 +++--- tools/perf/util/symbol.h | 10 ++++++++++ 3 files changed, 18 insertions(+), 4 deletions(-) diff --git a/tools/perf/Makefile b/tools/perf/Makefile index 742a32eee8fc..46e877b42d2a 100644 --- a/tools/perf/Makefile +++ b/tools/perf/Makefile @@ -422,7 +422,11 @@ ifeq ($(uname_S),Darwin) PTHREAD_LIBS = endif -ifneq ($(shell sh -c "(echo '\#include '; echo 'int main(void) { Elf * elf = elf_begin(0, ELF_C_READ_MMAP, 0); return (long)elf; }') | $(CC) -x c - $(ALL_CFLAGS) -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -o /dev/null $(ALL_LDFLAGS) > /dev/null 2>&1 && echo y"), y) +ifeq ($(shell sh -c "(echo '\#include '; echo 'int main(void) { Elf * elf = elf_begin(0, ELF_C_READ, 0); return (long)elf; }') | $(CC) -x c - $(ALL_CFLAGS) -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -o /dev/null $(ALL_LDFLAGS) > /dev/null 2>&1 && echo y"), y) + ifneq ($(shell sh -c "(echo '\#include '; echo 'int main(void) { Elf * elf = elf_begin(0, ELF_C_READ_MMAP, 0); return (long)elf; }') | $(CC) -x c - $(ALL_CFLAGS) -D_LARGEFILE64_SOURCE -D_FILE_OFFSET_BITS=64 -o /dev/null $(ALL_LDFLAGS) > /dev/null 2>&1 && echo y"), y) + BASIC_CFLAGS += -DLIBELF_NO_MMAP + endif +else msg := $(error No libelf.h/libelf found, please install libelf-dev/elfutils-libelf-devel and glibc-dev[el]); endif diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c index 47ea0609a760..226f44a2357d 100644 --- a/tools/perf/util/symbol.c +++ b/tools/perf/util/symbol.c @@ -413,7 +413,7 @@ static int dso__synthesize_plt_symbols(struct dso *self, int v) if (fd < 0) goto out; - elf = elf_begin(fd, ELF_C_READ_MMAP, NULL); + elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL); if (elf == NULL) goto out_close; @@ -533,7 +533,7 @@ static int dso__load_sym(struct dso *self, int fd, const char *name, Elf *elf; int nr = 0, kernel = !strcmp("[kernel]", self->name); - elf = elf_begin(fd, ELF_C_READ_MMAP, NULL); + elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL); if (elf == NULL) { if (v) fprintf(stderr, "%s: cannot read %s ELF file.\n", @@ -675,7 +675,7 @@ static char *dso__read_build_id(struct dso *self, int v) if (fd < 0) goto out; - elf = elf_begin(fd, ELF_C_READ_MMAP, NULL); + elf = elf_begin(fd, PERF_ELF_C_READ_MMAP, NULL); if (elf == NULL) { if (v) fprintf(stderr, "%s: cannot read %s ELF file.\n", diff --git a/tools/perf/util/symbol.h b/tools/perf/util/symbol.h index 6e8490716408..829da9edba64 100644 --- a/tools/perf/util/symbol.h +++ b/tools/perf/util/symbol.h @@ -27,6 +27,16 @@ static inline char *bfd_demangle(void __used *v, const char __used *c, #endif #endif +/* + * libelf 0.8.x and earlier do not support ELF_C_READ_MMAP; + * for newer versions we can use mmap to reduce memory usage: + */ +#ifdef LIBELF_NO_MMAP +# define PERF_ELF_C_READ_MMAP ELF_C_READ +#else +# define PERF_ELF_C_READ_MMAP ELF_C_READ_MMAP +#endif + #ifndef DMGL_PARAMS #define DMGL_PARAMS (1 << 0) /* Include function args */ #define DMGL_ANSI (1 << 1) /* Include const, volatile, etc */ From ec29b8d2af01912bb79adda8aeab4293539f29ac Mon Sep 17 00:00:00 2001 From: Paul Mundt Date: Mon, 26 Oct 2009 14:40:01 +0900 Subject: [PATCH 4/4] perf tools: Remove -Wcast-align The present use of -Wcast-align causes the build to blow up on SH due to generating a "cast increases required alignment of target type" error on each invocation of list_for_each_entry(). It seems that this was previously reported and killed off in the ia64 support patch, but nothing seems to have happened with that. Presumably the same problem still remains there, too. Signed-off-by: Paul Mundt LKML-Reference: <20091026054000.GA13517@linux-sh.org> Signed-off-by: Ingo Molnar --- tools/perf/Makefile | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/tools/perf/Makefile b/tools/perf/Makefile index 46e877b42d2a..7e190d522cd5 100644 --- a/tools/perf/Makefile +++ b/tools/perf/Makefile @@ -177,8 +177,7 @@ endif # Include saner warnings here, which can catch bugs: # -EXTRA_WARNINGS := -Wcast-align -EXTRA_WARNINGS := $(EXTRA_WARNINGS) -Wformat +EXTRA_WARNINGS := -Wformat EXTRA_WARNINGS := $(EXTRA_WARNINGS) -Wformat-security EXTRA_WARNINGS := $(EXTRA_WARNINGS) -Wformat-y2k EXTRA_WARNINGS := $(EXTRA_WARNINGS) -Wshadow