Hi Chen, > ... it was consistently (as in every run for 20 runs) faster, and thus I've > included it in the patch.
Thanks. I'll wait for the FSF notification that the legal papers have arrived. > This is not what I expected at all, and I'm having a hard time coming up with > a reason why this is 15 years ago, on a Linux/x86 machine, I could measure CPU performance with about 1% precision (with 3 or 5 runs of a program). At the same time, on Windows, I got only about 5% precision. On SPARC CPUs, sometimes the same program was 30% slower than the previous day. So, such platforms were unusable for benchmarking. Today, x86 CPUs have additional complexity: multiple CPU cores that fight over the memory bus; hyperthreads. The Linux memory management has become more complex as well (the kernel actively swapping out some pages). Sometimes you're even running inside a virtual machine. I usually can get only about 2% of precision nowadays. Bruno
