On Sat, Jan 29, 2011 at 09:55:06PM -0800, Robby Sun wrote: > I'd like to suggest that you use the same bit-width for 'Dummy' as that for > 'count', and initialize it to 0, so as to ensure that it won't overflow.
I don't use value of Dummy, overflow don't meaning. > -Robby > > On Fri, Jan 28, 2011 at 1:52 PM, Slawa Olhovchenkov <[email protected]> wrote: > > > On Sat, Jan 29, 2011 at 07:52:11AM +1100, Bruce Evans wrote: > > > > > >> there are of course several possible answers, including: > > > >> > > > >> 1/ Sometimes BSD and Linux report things differently. Linux may or may > > not > > > >> account for the lowest level interrupt tie the same as BSD > > > > > > > > But I see only 20% idle on FreeBSD and 80% idle on Linux. > > > > > > The time must be counted somewhere, so when it is not properly accounted > > > to packet handling, and nothing much else is running, it is accounted to > > > idle. > > > > > > To see how much CPU is actually available, run something else and see how > > > fast it runs. A simple counting loops works well on UP systems. > > > > === > > #include <stdio.h> > > #include <sys/time.h> > > > > int Dummy; > > > > int > > main(int argc, char *argv[]) > > { > > long int count,i,dt; > > struct timeval st,et; > > > > count = atol(argv[1]); > > > > gettimeofday(&st, NULL); > > for(i=count;i;i--) Dummy++; > > gettimeofday(&et, NULL); > > dt = (et.tv_sec-st.tv_sec)*1000000 + et.tv_usec-st.tv_usec; > > printf("Elapsed %d us\n",dt); > > } > > === > > > > This is ok? > > > > ./loop 2000000000 > > > > FreeBSD > > 1 process: Elapsed 7554193 us > > 2 process: Elapsed 14493692 us > > netperf + 1 process: Elapsed 21403644 us > > > > Linux > > 1 process: Elapsed 7524843 us > > 2 process: Elapsed 14995866 us > > netperf + 1 process: Elapsed 14107670 us > > > > > _______________________________________________ > [email protected] mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-performance > To unsubscribe, send any mail to "[email protected]" _______________________________________________ [email protected] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-performance To unsubscribe, send any mail to "[email protected]"
