Messages in this thread | | | Date | Mon, 23 Nov 2009 10:52:46 +0100 | From | Stanislaw Gruszka <> | Subject | Re: [PATCH] fix granularity of task_u/stime(), v2 |
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On Thu, Nov 12, 2009 at 03:49:19PM +0100, Stanislaw Gruszka wrote: > On Thu, Nov 12, 2009 at 01:33:45PM +0900, Hidetoshi Seto wrote: > > Originally task_s/utime() were designed to return clock_t but later > > changed to return cputime_t by following commit: > > > > commit efe567fc8281661524ffa75477a7c4ca9b466c63 > > Author: Christian Borntraeger <borntraeger@de.ibm.com> > > Date: Thu Aug 23 15:18:02 2007 +0200 > > > > It only changed the type of return value, but not the implementation. > > As the result the granularity of task_s/utime() is still that of > > clock_t, not that of cputime_t. > > > > So using task_s/utime() in __exit_signal() makes values accumulated > > to the signal struct to be rounded and coarse grained. > > > > This patch removes casts to clock_t in task_u/stime(), to keep > > granularity of cputime_t over the calculation. > > > > v2: > > Use div_u64() to avoid error "undefined reference to `__udivdi3`" > > on some 32bit systems. > > > > Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com> > > --- > > kernel/sched.c | 22 +++++++++++++--------- > > 1 files changed, 13 insertions(+), 9 deletions(-) > > Patch not fix the issue on my system. I test it alone, together with > > posix-cpu-timers: avoid do_sys_times() races with __exit_signal( > > and (further) together with > > --- a/kernel/posix-cpu-timers.c > +++ b/kernel/posix-cpu-timers.c > @@ -248,8 +248,8 @@ void thread_group_cputime(struct task_struct *tsk, > struct task_cputime *times) > > t = tsk; > do { > - times->utime = cputime_add(times->utime, t->utime); > - times->stime = cputime_add(times->stime, t->stime); > + times->utime = cputime_add(times->utime, task_utime(t)); > + times->stime = cputime_add(times->stime, task_stime(t)); > times->sum_exec_runtime += t->se.sum_exec_runtime; > > t = next_thread(t); > > What only changed was probability to enter the issue.
I was wrong here, that combination fix the problem on my system. I don't know how I was testing it before, perhaps I booted wrong kernel.
Stanislaw
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