On 07/08/2015 21:19, Jintack Lim wrote: > Hi all, > > While I was looking at rdtsc() code in kvm-unit-tests (e.g. x86/vmexit.c), > I was getting curious that out-of-order execution on the processor > may make rdtsc() executed not in the place we expect. > > Referring to this document from intel, > http://www.intel.com/content/www/us/en/embedded/training/ia-32-ia-64-benchmark-code-execution-paper.html > they suggested to use rdtscp instruction and other techniques to > serialize reading tsc register. > > I wonder how the serialization is achieved when using rdtsc() in > kvm-unit-tests code. > Or, maybe the serialization is not necessary for some reason? kvm-unit-tests executes the instruction thousands of times, so any error due to lack of serialization is lost in the noise. Paolo -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
