Messages in this thread | | | Subject | Re: Commit 1e5a74059f9 broke utime measurement of ptraced() processes | From | Mike Galbraith <> | Date | Sat, 24 Dec 2011 08:42:46 +0100 |
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On Sat, 2011-12-24 at 10:26 +0300, Артем Анисимов wrote:
> I believe that the described behaviour is erroneous and in order to > > lessen the odds of it [waker] being preempted again soon > one should not mess with utime but rather use another technique. It is also > interesting why the *user time* needs to be affected? It is inside the kernel > that the tracer process is woken up, so when > > handing a few wakeup expense cycles to the wakee > why not account those cycles as stime?
CPU utilization shifts with wakeup preemption, so there will be visible effect when you change wakeup preemption in any way.
> Also I'd like to know if there is a way to get reliable utime measurements > in recent kernels.
If wakeup preemption is undesirable, you could run SCHED_BATCH.
-Mike
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