Re: [PATCH] improve rwsem scalability (was Re: [CFT][RFC] HT scheduler)

[Nick Piggin]

Nick Piggin wrote:

> Nick Piggin wrote:
>
> > OK, this is an average of 5 runs at 145, 150, 155 rooms with my 
> > scheduler
> > patches, with and without my rwsem patch. Its all over the place, but 
> > I think
> > rwsem does give a small but significant improvement.
> >
> > http://www.kerneltrap.org/~npiggin/rwsem2.png
>
>
>
> What do you think? Is there any other sorts of benchmarks I should try?
> The improvement I think is significant, although volanomark is quite
> erratic and doesn't show it well.
>
> I don't see any problem with moving the wakeups out of the rwsem's 
> spinlock.

Actually my implementation does have a race because list_del_init isn't
atomic. Shouldn't be difficult to fix if anyone cares about it... otherwise
I won't bother.

Nick

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