Date: Fri, 5 May 2000 17:30:52 -0700 (PDT) From: Jean-Marc Zucconi <jmz@FreeBSD.org> To: current@FreeBSD.org Subject: Can someone explain this? Message-ID: <200005060030.RAA11795@freefall.freebsd.org>
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Here is something I don't understand:
$ sh -c '/usr/bin/time ./a.out'
2.40 real 2.38 user 0.01 sys
$ /usr/bin/time ./a.out
7.19 real 7.19 user 0.00 sys
The same program is 3 times slower in the second case. The effect is
systematic but depends on the program being run. I have seen inverse
behavior with another program.
Using time -l, I note that this seems to be related with a higher
value of 'involuntary context switches' (3 times more switches in the
slower case).
Running -current (SMP)
Here is my test program:
main ()
{
int i;
double x, y, z;
for (i = 0; i < 100000000; i++) z = y*x;
}
Jean-Marc
--
Jean-Marc Zucconi PGP Key: finger jmz@FreeBSD.org
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