From: Song Liu <song@kernel.org>
Date: Mon, 13 Mar 2023 17:16:08 +0000 (-0700)
Subject: perf: fix perf_event_context->time
X-Git-Tag: v6.6.7~3262^2~1
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=baf1b12a67f5b24f395baca03e442ce27cab0c18;p=platform%2Fkernel%2Flinux-starfive.git

perf: fix perf_event_context->time

Time readers rely on perf_event_context->[time|timestamp|timeoffset] to get
accurate time_enabled and time_running for an event. The difference between
ctx->timestamp and ctx->time is the among of time when the context is not
enabled. __update_context_time(ctx, false) is used to increase timestamp,
but not time. Therefore, it should only be called in ctx_sched_in() when
EVENT_TIME was not enabled.

Fixes: 09f5e7dc7ad7 ("perf: Fix perf_event_read_local() time")
Signed-off-by: Song Liu <song@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/r/20230313171608.298734-1-song@kernel.org
---

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 296617e..52b4aa0 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -3872,7 +3872,7 @@ ctx_sched_in(struct perf_event_context *ctx, enum event_type_t event_type)
 	if (likely(!ctx->nr_events))
 		return;
 
-	if (is_active ^ EVENT_TIME) {
+	if (!(is_active & EVENT_TIME)) {
 		/* start ctx time */
 		__update_context_time(ctx, false);
 		perf_cgroup_set_timestamp(cpuctx);