Re: How does 2.6 SMP scheduler initially assign a thread to a run queue?

[Siddha, Suresh B]

On Wed, Jun 08, 2005 at 06:11:55PM +0530, lk wrote:
> > In the 2.6 kernel, there is one run queue per CPU, in case of an SMP.
> > After a thread is created, how does the scheduler determine which run
> > queue it goes to?  
> 
> First it forked process (child) gets the same CPU as that of parent.
> forking a child gets the same CPU and later part of fork will call 
> wake_up_new_task () to fetch the run-queue of the CPU and 
> __activate_task () is called to move task into run-queue. 
> Later rescheduling of the process may move process to another
> run-queues.

In -mm kernels, Nick has recently added balance on exec/fork.

> > By the way, in an SMT/hyperthreading processor, does the latest kernel
> > version assign one run queue per physical CPU, or per virtual 
> > processor?
> > 
> 
> one run-queue per physical CPU

No. Each logical processor has its own runqueue.

thanks,
suresh
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