(4/27/13 12:40 AM), Olivier Langlois wrote: > > > Forbids the cputimer to drift ahead of its process clock by > blocking its update when a tick occurs while a autoreaping task > is currently in do_exit() between the call to release_task() and > its final call to schedule(). > > Any task stats update after having called release_task() will > be lost because they are added to the global process stats located > in the signal struct from release_task(). > > Ideally, you should postpone the release_task() call after the > final context switch to get all the stats added but this is > more complex to achieve. > > In other words, this is slowing down the cputimer so it keep the same > pace than the process clock but in fact, what should be done is to > speed up the process clock by adding the missing stats to it. > > Signed-off-by: Olivier Langlois <oliv...@trillion01.com> > --- > kernel/sched/fair.c | 10 +++++++++- > 1 file changed, 9 insertions(+), 1 deletion(-) > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index 7a33e59..52d7b10 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -708,7 +708,15 @@ static void update_curr(struct cfs_rq *cfs_rq) > > trace_sched_stat_runtime(curtask, delta_exec, curr->vruntime); > cpuacct_charge(curtask, delta_exec); > - account_group_exec_runtime(curtask, delta_exec); > + /* > + * Do not update the cputimer if the task is already released > by > + * release_task(). > + * > + * it would preferable to defer the autoreap release_task > + * after the last context switch but harder to do. > + */ > + if (likely(curtask->sighand)) > + account_group_exec_runtime(curtask, delta_exec); > }
I'm confused. glibc's rt/tst-cputimer1 doesn't have thread exiting code. I have no seen any issue in this accounting. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
