On April 5, 2015 3:05:18 PM EDT, Kristof Provost <kristof@xxxxxxxxxx> wrote: >On 2015-04-05 14:45:28 (-0400), Nicholas Krause <xerofoify@xxxxxxxxx> >wrote: >> >> >> On April 5, 2015 8:29:47 AM EDT, Kristof Provost <kristof@xxxxxxxxxx> >wrote: >> >On 2015-04-05 01:15:31 (-0400), Valdis.Kletnieks@xxxxxx >> ><Valdis.Kletnieks@xxxxxx> wrote: >> >> On Sat, 04 Apr 2015 19:00:42 -0400, Nicholas Krause said: >> >> > are now slower by up to 3 times, >> >> >> >> So what debugging did you already do to try to narrow this down? >> >> >> >While we're on the subject, let me indulge a pet peeve: How did you >> >measure this? Can you reproduce the measurement? Is the difference >> >statistically significant? What aspect of performance is worse? Task >> >switching time? IO throughput? >> > >> >Benchmarking is *hard*, and 'up to 3 times' is not the result of a >> >careful, well thought out benchmark. >> > >> I ran the make command on all of my CPU cores and timed it. >Furthermore it seems to be slower up to 3 times then my distribution >kernel based off 3.16. > >So, in other words, no, you've not done a careful benchmark at all. > >What's the standard deviation on both measurements? How confident are >you (your answer should be a number) that there is a difference? >How have you accounted for VFS cache effects? Have you ensured that >both >builds were from a completely clean tree? How have you ensured that no >other jobs interfered with the build (i.e. cron, user interaction, >...)? > >Once you've established that there really is a difference you need to >start isolating contributing factors and figure out what's causing the >difference. Alternatively, you can start trying to figure out which >part >of overall system performance has been degraded. That requires actually >understanding how the system works and using inspection tools (top, >iostat, perf, ...) to find out where the performance bottleneck is. > >None of that is easy or quick. None of these questions can be answered >in one quick sentence. Certainly your overall answer should include >more >information, and demonstrate more thought and effort, than 'I did a >build.'. > >Regards, >Kristof The only difference I can tell is the kernel version. I was wondering however if anyone who has more experience in the kernel can give me tips on how to address my benchmarking. Thanks, Nick -- Sent from my Android device with K-9 Mail. Please excuse my brevity. _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
