CPU selection for ithreads on 8.3

Navdeep Parhar np at FreeBSD.org
Fri May 4 18:00:10 UTC 2012


On 05/04/12 10:05, Wojciech Puchar wrote:
>> cxgbc0}
>> 12 root -68 - 0K 816K WAIT 7 0:31 0.00% intr{irq280: cxgbc0}
>>
>> Back in the day there used to be code in cxgb to bind different
>> interrupts to different CPUs but it was removed because the kernel
>> distributed them across CPUs anyway. So what changed? This appears 8.3
>> specific. I don't see it on head and I don't have a 9 system readily
>
> maybe stupid question but isn't it better to execute same fragment of
> code repetitively on same CPU core and don't mess with cache trashing?
>
> Of course as long as one core can cope with it.

That, and cache trashing is not that big an issue if the threads are 
working on their own sets of data.  This is precisely the problem that 
network stack parallelization tries to solve.

Navdeep


More information about the freebsd-hackers mailing list