From 5e2d4c81b9e4a82090ec44a24e84223e00a4c5fd Mon Sep 17 00:00:00 2001 From: David Ahern Date: Wed, 23 Oct 2013 16:53:05 +0100 Subject: [PATCH] perf: POSIX CLOCK_PERF to report current time value 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 struct timespec ts; clock_gettime(CLOCK_PERF, &ts); Signed-off-by: Pawel Moll Signed-off-by: David Ahern --- 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..9066bf02c867 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 b073975af05a..98c26fb1d9fd 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -39,6 +39,7 @@ #include #include #include +#include #include "internal.h" @@ -303,6 +304,19 @@ static inline u64 perf_clock(void) } #endif +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) { @@ -7878,6 +7892,10 @@ 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); @@ -7894,6 +7912,8 @@ 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)