Re: 2.6.14-rt22 (and mainline) excessive latency

Ingo Molnar
2005-12-20T04:25:23Z

* Lee Revell <rlrevell@joe-job.com> wrote:

> I captured this 3+ ms latency trace when killing a process with a few
> thousand threads. Can a cond_resched be added to this code path?

> bash-17992 0.n.1 29us : eligible_child (do_wait)
>
> [ 3000+ of these deleted ]
>
> bash-17992 0.n.1 3296us : eligible_child (do_wait)

Atomicity of signal delivery is pretty much a must, so i'm not sure this
particular latency can be fixed, short of running PREEMPT_RT. Paul E.
McKenney is doing some excellent stuff by RCU-ifying the task lookup and
signal code, but i'm not sure whether it could cover do_wait().

Ingo