Messages in this thread Patch in this message | | | From | David Ahern <> | Subject | [PATCH] perf: POSIX CLOCK_PERF to report current time value | Date | Tue, 10 Dec 2013 13:27:39 -0700 |
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From: Pawel Moll <pawel.moll@arm.com>
To co-relate user space events with the perf events stream a current (as in: "what time(stamp) is it now?") time value must be made available.
This patch adds a POSIX clock returning the perf_clock() value and accesible from userspace:
#include <time.h>
struct timespec ts;
clock_gettime(CLOCK_PERF, &ts);
Updated to 3.13
Signed-off-by: Pawel Moll <pawel.moll@arm.com> Signed-off-by: David Ahern <dsahern@gmail.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Stephane Eranian <eranian@google.com> Cc: John Stultz <john.stultz@linaro.org> Cc: Sonny Rao <sonnyrao@chromium.org> Cc: Thomas Gleixner <tglx@linutronix.de> --- include/uapi/linux/time.h | 1 + kernel/events/core.c | 20 ++++++++++++++++++++ 2 files changed, 21 insertions(+)
diff --git a/include/uapi/linux/time.h b/include/uapi/linux/time.h index e75e1b6ff27f..b07f07914a13 100644 --- a/include/uapi/linux/time.h +++ b/include/uapi/linux/time.h @@ -56,6 +56,7 @@ struct itimerval { #define CLOCK_BOOTTIME_ALARM 9 #define CLOCK_SGI_CYCLE 10 /* Hardware specific */ #define CLOCK_TAI 11 +#define CLOCK_PERF 12 #define MAX_CLOCKS 16 #define CLOCKS_MASK (CLOCK_REALTIME | CLOCK_MONOTONIC) diff --git a/kernel/events/core.c b/kernel/events/core.c index 72348dc192c1..87aa36ac68f7 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -39,6 +39,7 @@ #include <linux/hw_breakpoint.h> #include <linux/mm_types.h> #include <linux/cgroup.h> +#include <linux/posix-timers.h> #include "internal.h" @@ -295,6 +296,19 @@ static inline u64 perf_clock(void) return local_clock(); } +static int perf_posix_clock_getres(const clockid_t which_clock, + struct timespec *tp) +{ + *tp = ns_to_timespec(TICK_NSEC); + return 0; +} + +static int perf_posix_clock_get(clockid_t which_clock, struct timespec *tp) +{ + *tp = ns_to_timespec(perf_clock()); + return 0; +} + static inline struct perf_cpu_context * __get_cpu_context(struct perf_event_context *ctx) { @@ -7904,6 +7918,10 @@ perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu) void __init perf_event_init(void) { + struct k_clock perf_posix_clock = { + .clock_getres = perf_posix_clock_getres, + .clock_get = perf_posix_clock_get, + }; int ret; idr_init(&pmu_idr); @@ -7920,6 +7938,8 @@ void __init perf_event_init(void) ret = init_hw_breakpoint(); WARN(ret, "hw_breakpoint initialization failed with: %d", ret); + posix_timers_register_clock(CLOCK_PERF, &perf_posix_clock); + /* do not patch jump label more than once per second */ jump_label_rate_limit(&perf_sched_events, HZ); -- 1.8.3.4 (Apple Git-47)
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