* Davidlohr Bueso <davidlohr@xxxxxx> wrote: > Btw, do you suggest using a high level tool such as perf for getting > this data or sprinkling get_cycles() in find_vma() -- I'd think that the > first isn't fine grained enough, while the later will probably variate a > lot from run to run but the ratio should be rather constant. LOL - I guess I should have read your mail before replying to it ;-) Yes, I think get_cycles() works better in this case - not due to granularity (perf stat will report cycle granular just fine), but due to the size of the critical path you'll be measuring. You really want to extract the delta, because it's probably so much smaller than the overhead of the workload itself. [ We still don't have good 'measure overhead from instruction X to instruction Y' delta measurement infrastructure in perf yet, although Frederic is working on such a trigger/delta facility AFAIK. ] Thanks, Ingo -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>