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authorPeter Zijlstra <a.p.zijlstra@chello.nl>2012-01-30 14:51:37 +0100
committerIngo Molnar <mingo@elte.hu>2012-02-22 12:06:55 +0100
commit8c79a045fd590a26e81e75f5d8d4ec5c7d23e565 (patch)
tree8123849709e37dc2394373ad40cf333b2f19ebb5 /include
parent719741d9986572d64b47c35c09f5e7bb8d389400 (diff)
downloadlinux-linaro-stable-8c79a045fd590a26e81e75f5d8d4ec5c7d23e565.tar.gz
sched/events: Revert trace_sched_stat_sleeptime()
Commit 1ac9bc69 ("sched/tracing: Add a new tracepoint for sleeptime") added a new sched:sched_stat_sleeptime tracepoint. It's broken: the first sample we get on a task might be bad because of a stale sleep_start value that wasn't reset at the last task switch because the tracepoint was not active. It also breaks the existing schedstat samples due to the side effects of: - se->statistics.sleep_start = 0; ... - se->statistics.block_start = 0; Nor do I see means to fix it without adding overhead to the scheduler fast path, which I'm not willing to for the sake of redundant instrumentation. Most importantly, sleep time information can already be constructed by tracing context switches and wakeups, and taking the timestamp difference between the schedule-out, the wakeup and the schedule-in. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Andrew Vagin <avagin@openvz.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Link: http://lkml.kernel.org/n/tip-pc4c9qhl8q6vg3bs4j6k0rbd@git.kernel.org Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'include')
-rw-r--r--include/trace/events/sched.h50
1 files changed, 0 insertions, 50 deletions
diff --git a/include/trace/events/sched.h b/include/trace/events/sched.h
index 6ba596b07a72..e33ed1bfa113 100644
--- a/include/trace/events/sched.h
+++ b/include/trace/events/sched.h
@@ -370,56 +370,6 @@ TRACE_EVENT(sched_stat_runtime,
(unsigned long long)__entry->vruntime)
);
-#ifdef CREATE_TRACE_POINTS
-static inline u64 trace_get_sleeptime(struct task_struct *tsk)
-{
-#ifdef CONFIG_SCHEDSTATS
- u64 block, sleep;
-
- block = tsk->se.statistics.block_start;
- sleep = tsk->se.statistics.sleep_start;
- tsk->se.statistics.block_start = 0;
- tsk->se.statistics.sleep_start = 0;
-
- return block ? block : sleep ? sleep : 0;
-#else
- return 0;
-#endif
-}
-#endif
-
-/*
- * Tracepoint for accounting sleeptime (time the task is sleeping
- * or waiting for I/O).
- */
-TRACE_EVENT(sched_stat_sleeptime,
-
- TP_PROTO(struct task_struct *tsk, u64 now),
-
- TP_ARGS(tsk, now),
-
- TP_STRUCT__entry(
- __array( char, comm, TASK_COMM_LEN )
- __field( pid_t, pid )
- __field( u64, sleeptime )
- ),
-
- TP_fast_assign(
- memcpy(__entry->comm, tsk->comm, TASK_COMM_LEN);
- __entry->pid = tsk->pid;
- __entry->sleeptime = trace_get_sleeptime(tsk);
- __entry->sleeptime = __entry->sleeptime ?
- now - __entry->sleeptime : 0;
- )
- TP_perf_assign(
- __perf_count(__entry->sleeptime);
- ),
-
- TP_printk("comm=%s pid=%d sleeptime=%Lu [ns]",
- __entry->comm, __entry->pid,
- (unsigned long long)__entry->sleeptime)
-);
-
/*
* Tracepoint for showing priority inheritance modifying a tasks
* priority.