09.09.2013, 21:31, "David Miller" <davem@xxxxxxxxxxxxx>: > From: Kirill Tkhai <tkhai@xxxxxxxxx> > Date: Mon, 09 Sep 2013 18:50:00 +0400 > >> Before: >> >> real 7m58.466s >> user 60m49.660s >> sys 47m40.030s >> >> After: >> >> real 7m55.562s >> user 60m20.900s >> sys 46m36.040s >> >> So, the real profit (system time) is whole 2.2%. I thought, it would be more :) >> It seems, it's not big enough to really implement this feature. Practice checks >> a hypothesis. > > You are juding the suitability of your optimization using one > statistical sample of a benchmark involving trillions of memory > accesses? > Please at least run it 3 or 4 times so you can see how much variation > occurs between runs in the same configuration. :-) Yes, I compiled kernel 3 times for every case. Two above are middle results. Another cases are a little different, but tendency is like above. The low bound of difference is 2.0+% I did every test after cold start (and even took ethernet cable out). So, the result is honest :) (For comparison: Plain memory access time ratio between own node and its neighbour is about 1.4 on the tested machine. It looks like instruction cache has the influence on above result. I don't know what is its influence on machines of another type, maybe anywhere it is smaller). Kirill -- To unsubscribe from this list: send the line "unsubscribe sparclinux" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
