Messages in this thread |  | | Date | Thu, 28 Nov 2013 09:38:48 -0500 | From | Tejun Heo <> | Subject | Re: [PATCH]: exec: avoid propagating PF_NO_SETAFFINITY into userspace child |
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Hey, Peter.
On Thu, Nov 28, 2013 at 03:31:45PM +0100, Peter Zijlstra wrote: > But the WQ_UNBOUND thingies should be just that and should thus not have > the NO_SETAFFINITY flag set because there is no valid reason to have it > set. > > Regardless of whether the threads are shared between unbound workqueues > or not.
Hah? No, we do not want to allow userland to be able to set affinities on any workqueue workers, period. That's just inviting people to do weirdest things and then reporting things like "crypt jobs on some of our 500 machines end up stuck on a single cpu once in a while" which will eventually be tracked down to some weird shell script setting affinity on workers doing something else.
We really want to insulate workers and pool operation from userland. e.g. unbound workqueues now default to per-NUMA affinity unless explicitly told not to, which leads to better overall behavior for most workloads. We do wanna keep those details from userland so that they can be improved in the future too.
Thanks.
-- tejun
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