[erlang-questions] "processor affinity" for processes

Kenneth Lundin <>
Mon Jan 14 19:42:28 CET 2008


See questions below.

On Jan 10, 2008 3:24 PM, Zvi <> wrote:
>
> Another usefull feature will be specifying CPU Affinity for ports and
> external processes launched via os:cmd/1 .

This might be a potentially interesting feature, but what knowledge,
research or measurements do
you have which says that you get better performance with that feature?
>
> My current workarround is to launch script whcih temporary changing CPU
> affinity of the executable.

Can you explain more about this?
A workaround for what?
What do you want to achieve with explicit spec of CPU affinity?

Suppose you already use all processor cores or processors inside the
Erlang VM, how do
you then know if it pays off to specify a specific CPU for the external program?

/Kenneth Erlang/OTP team at Ericsson
>
> Zvi
>
>
>
> Vlad Dumitrescu-2 wrote:
> >
> > Thanks for the reply!
> >
> > regards,
> > Vlad
> >
> > On 4/12/07, Rickard Green <> wrote:
> >> Vlad Dumitrescu wrote:
> >> > Hi all,
> >> >
> >> > I can't find anything about this, and I suppose it's because there is
> >> > no such feature, but I wonder if it's possible to specify a "processor
> >> > affinity" for processes when run with the SMP VM.
> >> >
> >>
> >> There is no such feature.
> >>
> >> > A use-case would be to dedicate one processor/core for trace handlers,
> >> > loggers and other "peripheral" activities.
> >> >
> >> > Or maybe it doesn't matter in practice?
> >> >
> >>
> >> We have been talking about letting the emulator have more control over
> >> activities on the different cores, but this is still on the todo list.
> >> As it is today, the emulator creates X number of threads, and leave it
> >> up to the OS to distribute these threads over available cores.
> >>
> >> BR,
> >> Rickard Green, Erlang/OTP, Ericsson AB.
> >>
> >> > best regards,
> >> > Vlad
> >> > _______________________________________________
> >> > erlang-questions mailing list
> >> > 
> >> > http://www.erlang.org/mailman/listinfo/erlang-questions
> >> >
> >>
> > _______________________________________________
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> > 
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> >
> >
>
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