[RFC][PATCH 10/11] perf: Shrink hw_perf_event

Peter Zijlstra
2010-06-24T14:40:04Z

[-- Attachment #1: perf-swtimer-period_left.patch --]
[-- Type: text/plain, Size: 1701 bytes --]

Use hw_perf_event::period_left instead of hw_perf_event::remaning and
win back 8 bytes.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
---
include/linux/perf_event.h | 1 -
kernel/perf_event.c | 13 ++++++-------
2 files changed, 6 insertions(+), 8 deletions(-)

Index: linux-2.6/include/linux/perf_event.h
===================================================================
--- linux-2.6.orig/include/linux/perf_event.h
+++ linux-2.6/include/linux/perf_event.h
@@ -529,7 +529,6 @@ struct hw_perf_event {
int last_cpu;
};
struct { /* software */
- s64 remaining;
struct hrtimer hrtimer;
};
#ifdef CONFIG_HAVE_HW_BREAKPOINT
Index: linux-2.6/kernel/perf_event.c
===================================================================
--- linux-2.6.orig/kernel/perf_event.c
+++ linux-2.6/kernel/perf_event.c
@@ -4590,14 +4590,13 @@ static void perf_swevent_start_hrtimer(s
hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
hwc->hrtimer.function = perf_swevent_hrtimer;
if (hwc->sample_period) {
- u64 period;
+ s64 period = local64_read(&hwc->period_left);

- if (hwc->remaining) {
- if (hwc->remaining < 0)
+ if (period) {
+ if (period < 0)
period = 10000;
- else
- period = hwc->remaining;
- hwc->remaining = 0;
+
+ local64_set(&hwc->period_left, 0);
} else {
period = max_t(u64, 10000, hwc->sample_period);
}
@@ -4613,7 +4612,7 @@ static void perf_swevent_cancel_hrtimer(

if (hwc->sample_period) {
ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
- hwc->remaining = ktime_to_ns(remaining);
+ local64_set(&hwc->period_left, ktime_to_ns(remaining));

hrtimer_cancel(&hwc->hrtimer);
}