Re: [RFC] scheduler: improve SMP fairness in CFS

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Chris Snook wrote:

A fraction of *each* CPU, or a fraction of *total* CPU? Per-cpu granularity doesn't make anything more fair.

Well, our current solution uses per-cpu weights, because our vendor couldn't get the load balancer working accurately enough. Having per-cpu weights and cpu affinity gives acceptable results for the case where we're currently using it.

If the load balancer is good enough, per-system weights would be fine. It would have to play nicely with affinity though, in the case where it makes sense to lock tasks to particular cpus.

If I have two threads with the same priority, and two CPUs, the scheduler will put one on each CPU, and they'll run happily without any migration or balancing.

Sure. Now add a third thread. How often do you migrate? Put another way, over what time quantum do we ensure fairness?

Chris
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[Index of Archives]     [Kernel Newbies]     [Netfilter]     [Bugtraq]     [Photo]     [Stuff]     [Gimp]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Video 4 Linux]     [Linux for the blind]     [Linux Resources]
  Powered by Linux