Messages in this thread | | | Date | Thu, 14 Aug 2008 09:13:37 -0700 | From | "H. Peter Anvin" <> | Subject | Re: [RFC PATCH] x86 alternatives : fix LOCK_PREFIX race with preemptible kernel and CPU hotplug |
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Mathieu Desnoyers wrote: > > I can't argue about the benefit of using VM CPU pinning to manage > resources because I don't use it myself, but I ran some tests out of > curiosity to find if uncontended locks were that cheap, and it turns out > they aren't. Here are the results : > > Xeon 2.0GHz > > Summary > > make -j1 kernel/ 33.94 +/- 0.07 34.91 +/- 0.27 2.8 % > hackbench 50 2.99 +/- 0.01 3.74 +/- 0.01 25.1 % > > 1 CPU, replace smp lock prefixes with DS segment selector prefixes > 1 CPU, noreplace-smp
For reference, could you also compare replace smp lock with NOPs?
-hpa
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