Messages in this thread |  | | Date | Fri, 5 Sep 2008 18:15:16 +0200 | | From | Ingo Molnar <> | | Subject | Re: Still seeing decreasing stime/utime |
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* Peter Zijlstra <a.p.zijlstra@chello.nl> wrote:
> On Sat, 2008-08-30 at 19:25 +0530, Balbir Singh wrote: > > * Peter Zijlstra <a.p.zijlstra@chello.nl> [2008-08-30 13:27:36]: > > > > > On Sat, 2008-08-30 at 11:26 +0530, Balbir Singh wrote: > > > > Spencer Candland wrote: > > > > >> Here is an experimental patch (I've just compiled and booted a machine > > > > >> with it, I am unable to reproduce your problem), could you please test > > > > >> it for me and see if it helps solve the problem > > > > > > > > > > Looks like this fixed it. I have been testing this for the last 16 > > > > > hours and everything is looking good. > > > > > > > > > > > > > Excellent! Ingo, Peter, do you like the patch? If so, could you please pick it > > > > up Ingo. I think we should even push the fix to stable releases. > > > > > > Looks good, except for the issue you yourself earlier raised, a few of > > > those functions looks too large to be inlined. > > > > > > > Here's the updated revision with task_*time functions moved to sched.c > > and inlining removed, except for task_gtime(). I've compiled and > > booted a machine (x86_64) with this patch applied. > > > > Reported-by: spencer@bluehost.com > > > > Spencer reported a problem where utime and stime were going negative despite > > the fixes in commit b27f03d4bdc145a09fb7b0c0e004b29f1ee555fa. The suspected > > reason for the problem is that signal_struct maintains it's own utime and > > stime (of exited tasks), these are not updated using the new task_utime() > > routine, hence sig->utime can go backwards and cause the same problem > > to occur (sig->utime, adds tsk->utime and not task_utime()). This patch > > fixes the problem > > > > TODO: using max(task->prev_utime, derived utime) works for now, but a more > > generic solution is to implement cputime_max() and use the cputime_gt() > > function for comparison. > > > > Comments? > > > > Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com> > > Thanks Balbir! > > Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
applied to tip/sched/urgent, thanks!
Ingo
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