Re: [Jack-Devel] How does jackdmp set CPU affinity ?
Le 7 juil. 2011 à 22:50, karthik poduval a écrit :
> Hi All,
>
> I have been reading about jackdmp and how it can run client process callbacks(that are independent) on different cpu's on an smp machine from this document.
> http://www.grame.fr/Ressources/pub/Jackdmp-lac2005.pdf
>
> I had a couple of questions about it.
>
> 1. How does jackdmp assign a process callback thread to a given CPU ? I was expecting a call to pthread_setaffinity somewhere in the code but did not find it being used.
Is does not. What jack2 does is a "data flow like" client graph activation model, then use the regular scheduler without any more tricks.
>
> 2. From which version of jack2 is this mp feature enabled ? I am using jack1.9.5, is this version mp capable ?
From jackdmp "day one" (back in 2005)
>
> 3. Do I need to specify any command line option while starting the jackd to enable this feature or perhaps set some command line option to waf while compiling it ?
Nope.
>
> I am running jackd on a Linux machine that runs a Fedora 12 distro. The CPU is a dual core Intel Atom (Intel(R) Atom(TM) CPU D510 @ 1.66GHz).
>
> I checked the cpu assignment for jackd and its clients using the ps command and found the cpu assignment to vary every time I ran the command.
>
>
> 2853 1 FF 10 50 - jackd -dalsa -P
> 2857 1 FF 5 45 - jack_multiple_metro
> 2857 1 FF 5 45 - jack_multiple_metro
> 2857 1 FF 5 45 - jack_multiple_metro
> 2857 1 FF 5 45 - jack_multiple_metro
> 2857 1 FF 5 45 - jack_multiple_metro (This time all threads on CPU1)
>
> 2853 0 FF 10 50 - jackd -dalsa -P
> 2857 0 FF 5 45 - jack_multiple_metro
> 2857 0 FF 5 45 - jack_multiple_metro
> 2857 0 FF 5 45 - jack_multiple_metro
> 2857 1 FF 5 45 - jack_multiple_metro
> 2857 1 FF 5 45 - jack_multiple_metro (2 threads on CPU 1 and 4 on CPU0)
>
>
Yep. No CPU affinitiy.
Stéphane
1310072291.2635_0.ltw:2,a <F8F7687D-33D5-4075-BB2E-62DF60768143 at grame dot fr>