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perf: Add wakeup watermark control to the AUX area

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When AUX area gets a certain amount of new data, we want to wake up
userspace to collect it. This adds a new control to specify how much
data will cause a wakeup. This is then passed down to pmu drivers via
output handle's "wakeup" field, so that the driver can find the nearest
point where it can generate an interrupt.

We repurpose __reserved_2 in the event attribute for this, even though
it was never checked to be zero before, aux_watermark will only matter
for new AUX-aware code, so the old code should still be fine.

Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kaixu Xia <kaixu.xia@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Robert Richter <rric@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: acme@infradead.org
Cc: adrian.hunter@intel.com
Cc: kan.liang@intel.com
Cc: markus.t.metzger@intel.com
Cc: mathieu.poirier@linaro.org
Link: http://lkml.kernel.org/r/1421237903-181015-10-git-send-email-alexander.shishkin@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Alexander Shishkin
2015-01-14 14:18:18 +02:00
committed by Ingo Molnar
parent 2023a0d282
commit 1a59413124
4 changed files with 31 additions and 5 deletions
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7
include/uapi/linux/perf_event.h
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@@ -261,6 +261,7 @@ enum perf_event_read_format {
#define PERF_ATTR_SIZE_VER3 96 /* add: sample_regs_user */
/* add: sample_stack_user */
#define PERF_ATTR_SIZE_VER4 104 /* add: sample_regs_intr */
#define PERF_ATTR_SIZE_VER5 112 /* add: aux_watermark */
/*
* Hardware event_id to monitor via a performance monitoring event:
@@ -366,6 +367,12 @@ struct perf_event_attr {
* See asm/perf_regs.h for details.
*/
__u64 sample_regs_intr;
/*
* Wakeup watermark for AUX area
*/
__u32 aux_watermark;
__u32 __reserved_2; /* align to __u64 */
};
#define perf_flags(attr) (*(&(attr)->read_format + 1))