Re: Strange interaction between latencytop and the scheduler

Török Edwin wrote: Latencytop userspace tool shows latencies > 0.1 msec, thus capturing backtraces for latencies <0.1msec could be avoided. If I apply the patch below, then enabling latencytop doesn't freeze X when running the "10-threads doing infloop usleep(1)" test. ok I like the idea; I wo

Re: Strange interaction between latencytop and the scheduler

Török Edwin wrote: > >> The performance aspect... collecting the data isn't cheap (which is >> why it's made a sysctl), >> I still plan to look at optimizing it but it won't ever be free. >> > > Yes, I understand that. Is there a way latencytop could track its own > overhead? I suppose it w

Re: Strange interaction between latencytop and the scheduler

Arjan van de Ven wrote: > Török Edwin wrote: >> Is this normal? (is overhead really 40msec?) > > I'm seeing similar, I would not rule out that this is actual scheduler > behavior ;( > at least it seems consistent. Ok, it is good that we are seeing same behaviour. > I also made a patch (to lkml ye

Re: Strange interaction between latencytop and the scheduler

Török Edwin wrote: Hi Arjan, Ingo, [for minor latencytop userspace specific issues see at end of mail] * if I compile with CONFIG_SCHED_DEBUG I see a 30-40msec latency from the scheduler, always (Scheduler: waiting for cpu). There is also a constant ~5% user, ~2% sys CPU usage on an idle syst

Strange interaction between latencytop and the scheduler

Hi Arjan, Ingo, I am using latest latencytop from git (commit 92b6ca9d40998697866689f64b95647eca3200cb), and I'm seeing some strange things: [for minor latencytop userspace specific issues see at end of mail] * if I compile with CONFIG_SCHED_DEBUG I see a 30-40msec latency from the scheduler, alw