Setting CPU affinity to process( Freebsd smp kernel)

[Robert Watson]

On Wed, 21 Feb 2007, Kunze, Aaron wrote:

> Does anyone know if this will change any time soon?  For example, is anyone 
> working on exposing affinity to user-space applications via extensions of 
> the pthreads interface?
>
> Sorry to reply to such an old thread...

I know of no work along these lines currently, but it's something a lot of 
people would like to see happen.  There's a potential for conflict between the 
kernel's use of pinning and binding for kernel synchronization and the user 
space affinity model, which will be entirely avoided if done right. :-)  For 
now, it's quite easy to add a sysctl/syscall that allows user space to send 
the kernel scheduler's notion of thread binding, but this isn't really the 
right approach.  As I understand it, some systems support setting CPU affinity 
for a thread as a set of CPUs it is willing to run on ?

Robert N M Watson
Computer Laboratory
University of Cambridge

>
> Aaron
>
> ---------------
>
> On Monday 20 November 2006 06:24, Ashok TM wrote:
>> Hello,
>>
>> Is there a way to set   a process's CPU affinity  with  freebsd  smp
> kernel.
>>  By doing so a process is bound to and will only run on the processor
> (where
>> the affinity was set ) even though the other processors are free.
> (similar
>> to sched_setaffinity available on Linux kernel) .
>>
>> Does  freebsd smp scheduler supports setting affinity?
>
> Yes, but currently only in the kernel.
>
> -- 
> John Baldwin
>
>
> --------------------------
> Aaron Kunze
> aaron.kunze at intel.com
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