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Date:      Fri, 04 May 2001 02:15:44 CDT
From:      dave <dleimbac@earthlink.net>
To:        freebsd-questions@freebsd.org
Subject:   Curious gettimeofday problem/issue
Message-ID:  <200105041213.FAA20494@hawk.mail.pas.earthlink.net>

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http://www-106.ibm.com/developerworks/linux/library/l-rt1/

Has an article using gettimeofday vs and a equivalent function in Windows
to test some aspects of system performance.  There is a loop of
approximately 1 million calls to gettimeofday ran 20 times.  Each of these
1million calls has a final elapsed time and then the average time/call is
printed.  The source for these tests is available at the above link.

I decided to run this test with FBSD and was shocked and horrified.

The tests that the author of the above article ran showed Linux to be 2.5
times faster than Windows for that test.   By the same token Linux was
shown to be more than 13 times faster than FBSD.

Now this doesn't mean that all of FBSD is slower than linux but definitely
true on this test.

gettimeofday is a glibc library call.  Perhaps the way it gets its
information from the kernel is sub-optimal.   Perhaps the kernel's way of
providing this information is sub-optimal.  

Or what I am really hoping is that  my kernel is not optimally configured
<my fault> and that someone else will run this test and show there is no
bug in the kernel or glibc.

Dave Leimbach

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