Re: [CFT][RFC] HT scheduler

[Nick Piggin]

William Lee Irwin III wrote:

> William Lee Irwin III wrote:
>
> > > If this thing is heavily threaded, it could be mm->page_table_lock.
>
> On Fri, Dec 12, 2003 at 12:09:04AM +1100, Nick Piggin wrote:
>
> > I'm not sure how threaded it is, probably very. Would inline spinlocks
> > help show up mm->page_table_lock?
> > It really looks like .text.lock.futex though, doesn't it? Would that be
> > the hashed futex locks? I wonder why it suddenly goes downhill past about
> > 140 rooms though.
>
> It will get contention anyway if they're all pounding on the same futex.
> OTOH, if they're all threads in the same process, they can hit other
> problems. I'll try to find out more about hackbench.


Oh, sorry I was talking about volanomark. hackbench AFAIK doesn't use
futexes at all, just pipes, and is not threaded at all, so it looks like
a different problem to the volanomark one.

hackbench runs into trouble at large numbers of tasks too though.


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