Re: [PATCH] Fix delay accounting regression
* Balbir Singh <[EMAIL PROTECTED]> wrote: > 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? thanks, applied. Ingo - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] Fix delay accounting regression
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
19:02:07.0 +0530
+++ linux-2.6-latest-balbir/kernel/sched_stats.h2007-11-02
22:11:21.0 +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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Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] Fix delay accounting regression
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? Applications I can think of are 1. iotop 2. Some typical applications are mentioned in https://ols2006.108.redhat.com/2007/Reprints/nagar-Reprint.pdf > We have most of this data available under SCHEDSTATS - how about > consolidating CONFIG_TASK_DELAY_ACCT into CONFIG_SCHEDSTATS? > > Ingo Yes, we do use schedstats - except for two cases that I know of? 1. To accumulate information in taskstats to share with user space (we copy the data from schedstats into taskstats) 2. We accumulate the data for dead threads in a thread group -- Warm Regards, Balbir Singh Linux Technology Center IBM, ISTL - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] Fix delay accounting regression
On 11/2/07, Ingo Molnar <[EMAIL PROTECTED]> wrote: > What user-space tools are utilizing delay-accounting by the way? Thanks for the plugging opportunity ;-) http://guichaz.free.fr/misc/#iotop uses the I/O side of delay-accounting. -- Guillaume - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] Fix delay accounting regression
* 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 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
[PATCH] Fix delay accounting regression
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 |4 ++--
1 file changed, 2 insertions(+), 2 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
19:02:07.0 +0530
+++ linux-2.6-latest-balbir/kernel/sched_stats.h2007-11-02
19:51:30.0 +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
@@ -231,5 +231,5 @@ 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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the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
