From owner-freebsd-current  Fri May  5 17:30:57 2000
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From: Jean-Marc Zucconi <jmz@FreeBSD.org>
To: current@FreeBSD.org
Subject: Can someone explain this?
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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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