CPU selection for ithreads on 8.3

Navdeep Parhar np at FreeBSD.org
Wed May 2 21:48:24 UTC 2012


On 05/02/12 14:44, Ryan Stone wrote:
> On Wed, May 2, 2012 at 5:39 PM, Navdeep Parhar<np at freebsd.org>  wrote:
>> I will try it.  But would this explain why it used to work with 8.2 but
>> broke in 8.3?
>>
>> Navdeep
>
> If other driver changed between 8.2 and 8.3 to start binding intr
> threads to CPUs then your driver would inherit the last pinning.  Or
> even if your driver is now attaching after another driver.

But wouldn't _all_ of the driver's intr threads inherit the last 
pinning, whatever it was?  I'm saying that on 8.2 the 9 different 
threads used to bind to different CPUs automatically (provided enough 
CPUs were available) but now they all bind to the same CPU.

Anyway I'll try out the rev you pointed at then we'll work backwards 
towards an explanation if it works :-)

Navdeep




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