Hi, On 09/24, Michael Holzheu wrote: > > On Thu, 2010-09-23 at 19:10 +0200, Oleg Nesterov wrote: > > > > On 09/23, Michael Holzheu wrote: > > > > > > Currently there are code pathes (e.g. for kthreads) where the consumed > > > CPU time is not accounted to the parents cumulative counters. > > > > Could you explain more? > > I think one place was "khelper" (kmod.c). It is created with > kernel_thread() and it exits without having accounted the times with > sys_wait() to the parent's ctimes No. Well yes, it is not accounted, but this is not because it is kthread. To simplify the discussion, lets talk about utime/cutime only, and lets forget about the multithreading. It is very simple, currently linux accounts the exiting task's utime and adds its to ->cutime _only_ if parent does do_wait(). If parent ignores SIGCHLD, the child reaps itself and it is not accounted. I do not know why it was done this way, but I'm afraid we can't change this historical behaviour. > Ok, the problem is that I did not consider exiting threads that are no > thread group leaders. When they exit the ctime of the parent is not > updated. Instead the time is accumulated in the signal struct. I think I am a bit confused, but see above. With or without threads the whole process can exit without accounting. Oleg. -- To unsubscribe from this list: send the line "unsubscribe linux-s390" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
