diff options
| author | David Carrillo-Cisneros <davidcc@google.com> | 2016-08-17 13:55:06 -0700 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2016-08-18 10:53:59 +0200 |
| commit | d6a2f9035bfc27d0e9d78b13635dda9fb017ac01 (patch) | |
| tree | ff202f5400841b1714a1fe4a61682f75b614e742 /include/linux/perf_event.h | |
| parent | 4ff6a8debf48a7bf48e93c01da720785070d3a25 (diff) | |
perf/core: Introduce PMU_EV_CAP_READ_ACTIVE_PKG
Introduce the flag PMU_EV_CAP_READ_ACTIVE_PKG, useful for uncore events,
that allows a PMU to signal the generic perf code that an event is readable
in the current CPU if the event is active in a CPU in the same package as
the current CPU.
This is an optimization that avoids a unnecessary IPI for the common case
where uncore events are run and read in the same package but in
different CPUs.
As an example, the IPI removal speeds up perf_read() in my Haswell system
as follows:
- For event UNC_C_LLC_LOOKUP: From 260 us to 31 us.
- For event RAPL's power/energy-cores/: From to 255 us to 27 us.
For the optimization to work, all events in the group must have it
(similarly to PERF_EV_CAP_SOFTWARE).
Signed-off-by: David Carrillo-Cisneros <davidcc@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Carrillo-Cisneros <davidcc@google.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul Turner <pjt@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vegard Nossum <vegard.nossum@gmail.com>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: http://lkml.kernel.org/r/1471467307-61171-4-git-send-email-davidcc@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'include/linux/perf_event.h')
| -rw-r--r-- | include/linux/perf_event.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h index 6f7459f72dfd..5c5362584aba 100644 --- a/include/linux/perf_event.h +++ b/include/linux/perf_event.h @@ -514,8 +514,11 @@ typedef void (*perf_overflow_handler_t)(struct perf_event *, * Event capabilities. For event_caps and groups caps. * * PERF_EV_CAP_SOFTWARE: Is a software event. + * PERF_EV_CAP_READ_ACTIVE_PKG: A CPU event (or cgroup event) that can be read + * from any CPU in the package where it is active. */ #define PERF_EV_CAP_SOFTWARE BIT(0) +#define PERF_EV_CAP_READ_ACTIVE_PKG BIT(1) #define SWEVENT_HLIST_BITS 8 #define SWEVENT_HLIST_SIZE (1 << SWEVENT_HLIST_BITS) |