[tip:perf/core] perf: Change and simplify ctx::is_active semantics

From: tip-bot for Peter Zijlstra
Date: Sat May 28 2011 - 12:41:13 EST


Commit-ID: db24d33e08b88e990991760a44d72006a5dc6102
Gitweb: http://git.kernel.org/tip/db24d33e08b88e990991760a44d72006a5dc6102
Author: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
AuthorDate: Sat, 9 Apr 2011 21:17:45 +0200
Committer: Ingo Molnar <mingo@xxxxxxx>
CommitDate: Sat, 28 May 2011 18:01:17 +0200

perf: Change and simplify ctx::is_active semantics

Instead of tracking if a context is active or not, track which events
of the context are active. By making it a bitmask of
EVENT_PINNED|EVENT_FLEXIBLE we can simplify some of the scheduling
routines since it can avoid adding events that are already active.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Link: http://lkml.kernel.org/r/20110409192141.930282378@xxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
---
kernel/events/core.c | 14 ++++++++------
1 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 60b333a..71c2d44 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -1763,8 +1763,9 @@ static void ctx_sched_out(struct perf_event_context *ctx,
enum event_type_t event_type)
{
struct perf_event *event;
+ int is_active = ctx->is_active;

- ctx->is_active = 0;
+ ctx->is_active &= ~event_type;
if (likely(!ctx->nr_events))
return;

@@ -1774,12 +1775,12 @@ static void ctx_sched_out(struct perf_event_context *ctx,
return;

perf_pmu_disable(ctx->pmu);
- if (event_type & EVENT_PINNED) {
+ if ((is_active & EVENT_PINNED) && (event_type & EVENT_PINNED)) {
list_for_each_entry(event, &ctx->pinned_groups, group_entry)
group_sched_out(event, cpuctx, ctx);
}

- if (event_type & EVENT_FLEXIBLE) {
+ if ((is_active & EVENT_FLEXIBLE) && (event_type & EVENT_FLEXIBLE)) {
list_for_each_entry(event, &ctx->flexible_groups, group_entry)
group_sched_out(event, cpuctx, ctx);
}
@@ -2058,8 +2059,9 @@ ctx_sched_in(struct perf_event_context *ctx,
struct task_struct *task)
{
u64 now;
+ int is_active = ctx->is_active;

- ctx->is_active = 1;
+ ctx->is_active |= event_type;
if (likely(!ctx->nr_events))
return;

@@ -2070,11 +2072,11 @@ ctx_sched_in(struct perf_event_context *ctx,
* First go through the list and put on any pinned groups
* in order to give them the best chance of going on.
*/
- if (event_type & EVENT_PINNED)
+ if (!(is_active & EVENT_PINNED) && (event_type & EVENT_PINNED))
ctx_pinned_sched_in(ctx, cpuctx);

/* Then walk through the lower prio flexible groups */
- if (event_type & EVENT_FLEXIBLE)
+ if (!(is_active & EVENT_FLEXIBLE) && (event_type & EVENT_FLEXIBLE))
ctx_flexible_sched_in(ctx, cpuctx);
}

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