Re: [patch] sched: introduce SD_BALANCE_FORK for ht/mc/smp domains

Ingo Molnar
2007-07-26T22:18:55Z

* Siddha, Suresh B <suresh.b.siddha@intel.com> wrote:

> Introduce SD_BALANCE_FORK for HT/MC/SMP domains.
>
> For HT/MC, as caches are shared, SD_BALANCE_FORK is the right thing to
> do. Given that NUMA domain already has this flag and the scheduler
> currently doesn't have the concept of running threads belonging to a
> process as close as possible(i.e., forking may keep close, but
> periodic balance later will likely take them far away), introduce
> SD_BALANCE_FORK for SMP domain too.
>
> Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>

i'm not opposed to this fundamentally, but it would be nice to better
map the effects of this change: do you have any particular workload
under which you've tested this and under which you've seen it makes a
difference? I'd expect this to improve fork-intense half-idle workloads
perhaps - things like a make -j3 on a 4-core CPU.

Ingo