On Fri, Nov 02, 2007 at 04:53:58PM +0100, Ingo Molnar wrote:
>
> * Balbir Singh <[EMAIL PROTECTED]> wrote:
>
> > Fix the delay accounting regression introduced by commit
> > 75d4ef16a6aa84f708188bada182315f80aab6fa. rq no longer has sched_info
> > data associated with it. task_struct sched_info structure is used by
> > delay accounting to provide back statistics to user space.
>
> no, this really is broken code. sched_clock() is not a generally
> reliable time source so at a minimum the rq->clock fix i mentioned is
> needed. What user-space tools are utilizing delay-accounting by the way?
> We have most of this data available under SCHEDSTATS - how about
> consolidating CONFIG_TASK_DELAY_ACCT into CONFIG_SCHEDSTATS?
>
> Ingo
Hi, Ingo,
How about this?
Changelog
1. As per Ingo Molnar's recommendation, use rq->clock instead of sched_clock().
Fix the delay accounting regression introduced by commit
75d4ef16a6aa84f708188bada182315f80aab6fa. rq no longer has sched_info
data associated with it. task_struct sched_info structure is used by delay
accounting to provide back statistics to user space.
Signed-off-by: Balbir Singh <[EMAIL PROTECTED]>
---
kernel/sched_stats.h | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)
diff -puN kernel/sched_stats.h~delayacct-define-bug kernel/sched_stats.h
--- linux-2.6-latest/kernel/sched_stats.h~delayacct-define-bug 2007-11-02
19:02:07.000000000 +0530
+++ linux-2.6-latest-balbir/kernel/sched_stats.h 2007-11-02
22:11:21.000000000 +0530
@@ -127,7 +127,7 @@ rq_sched_info_depart(struct rq *rq, unsi
# define schedstat_set(var, val) do { } while (0)
#endif
-#ifdef CONFIG_SCHEDSTATS
+#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
/*
* Called when a process is dequeued from the active array and given
* the cpu. We should note that with the exception of interactive
@@ -155,7 +155,7 @@ static inline void sched_info_dequeued(s
*/
static void sched_info_arrive(struct task_struct *t)
{
- unsigned long long now = sched_clock(), delta = 0;
+ unsigned long long now = task_rq(t)->clock, delta = 0;
if (t->sched_info.last_queued)
delta = now - t->sched_info.last_queued;
@@ -186,7 +186,7 @@ static inline void sched_info_queued(str
{
if (unlikely(sched_info_on()))
if (!t->sched_info.last_queued)
- t->sched_info.last_queued = sched_clock();
+ t->sched_info.last_queued = task_rq(t)->clock;
}
/*
@@ -195,7 +195,8 @@ static inline void sched_info_queued(str
*/
static inline void sched_info_depart(struct task_struct *t)
{
- unsigned long long delta = sched_clock() - t->sched_info.last_arrival;
+ unsigned long long delta = task_rq(t)->clock -
+ t->sched_info.last_arrival;
t->sched_info.cpu_time += delta;
rq_sched_info_depart(task_rq(t), delta);
@@ -231,5 +232,5 @@ sched_info_switch(struct task_struct *pr
#else
#define sched_info_queued(t) do { } while (0)
#define sched_info_switch(t, next) do { } while (0)
-#endif /* CONFIG_SCHEDSTATS */
+#endif /* CONFIG_SCHEDSTATS || CONFIG_TASK_DELAY_ACCT */
_
--
Warm Regards,
Balbir Singh
Linux Technology Center
IBM, ISTL
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