On Thu, May 15, 2014 at 8:19 AM, Benedikt Grundmann <bgrundm...@janestreet.com> wrote: > I posted this on this mailing list before at Jane Street we have developed > very fast code to get timing information based on TSC if available. It's > all ocaml but well documented and mostly just calls to c functions so should > be easy to port to C and we release it under a very liberal license so it > should be no problem to take the ideas:
What OS do you run it on though? How fast is your implementation compared to the kernel implementation of clock_gettime()? Are you sure your implementation is actually faster? And are you sure you're protected against clocks going backwards? I think you should put some i/o in the loop in the test and start several threads running it to make it more likely the thread is rescheduled to a different processor during the test. It suspect you'll find the rdtsc goes backwards sometimes or produces crazy results when switching processors. -- greg -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
