Ingo Molnar wrote:
> * Balbir Singh <[EMAIL PROTECTED]> wrote:
>
>> If you insist that sched_yield() is bad, I might agree, but how does
>> my patch make things worse. [...]
>
> it puts new instructions into the hotpath.
>
>> [...] In my benchmarks, it has helped the sched_yield case, why is
>> that bad? [...]
>
> I had the same cache for the rightmost task in earlier CFS (it's a
> really obvious thing) but removed it. It wasnt a bad idea, but it hurt
> the fastpath hence i removed it. Algorithms and implementations are a
> constant balancing act.
This is more convincing, was the code ever in git? How did you measure the
overhead? What are your plans for reports with regressions where
kernel.compat_sched_yield is set to 1?
I have an alternate approach in mind (that I need to find time for),
threaded-rbtrees. Walking the tree is really efficient, specially finding
successor of a node.
--
Warm Regards,
Balbir Singh
Linux Technology Center
IBM, ISTL
--
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/
