Messages in this thread | | | From | Andi Kleen <> | Subject | Re: [PATCH 2/2] i386 TIF flags for debug regs and io bitmap in ctxsw | Date | Tue, 4 Jul 2006 23:47:00 +0200 |
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On Tuesday 04 July 2006 23:19, Chuck Ebbert wrote: > In-Reply-To: <20060704072939.GC5902@frankl.hpl.hp.com> > > On Tue, 4 Jul 2006 00:29:39 -0700, Stephane Eranian wrote: > > Following my discussion with Andi. Here is a patch that introduces > > two new TIF flags to simplify the context switch code in __switch_to(). > > The idea is to minimize the number of cache lines accessed in the common > > case, i.e., when neither the debug registers nor the I/O bitmap are used. > > I get a 5-10% speedup in task switch times with this patch.
That sounds too much. How did you measure it?
Note that lmbench tends to be unstable for this.
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