Re: [RFC PATCH] qspinlock: Improve performance by reducing load instruction rollback

From: Peter Zijlstra
Date: Tue Oct 20 2015 - 05:15:36 EST


On Tue, Oct 20, 2015 at 10:57:53AM +0800, Ling Ma wrote:
> >
> > So it would be nice to create a new user-space spinlock testing facility, via a
> > new 'perf bench spinlock' feature or so. That way others can test and validate
> > your results on different hardware as well.
> >
> Attached the spinlock test module . Queued spinlock will run very
> slowly in user space
> because process switch context, it is OK for spinlock-test
> implementation with kernel module ?

Works just fine in userspace if you pin each thread to a cpu and ensure
there's nothing else running on the system.

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