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From: Simon Wright <simon@pushface.org>
Newsgroups: comp.lang.ada
Subject: Re: Need some light on using Ada or not
Date: Sun, 20 Feb 2011 22:47:05 +0000
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Date: 2011-02-20T22:47:05+00:00
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Brian Drummond <brian_drummond@btconnect.com> writes:

> the 100% overhead (on this test case) imposed by the pthread library
> (which I think is how Gnat implements its tasking)

Here (Mac OS X, GCC 4.6.0 x86_64 experimental), I tried modifying the
Ada code to use the same tasking (threading) structure as the C GNU GCC
#5 version. Result (I only checked with parameter 16):

C:           real 5.1 user 9.0
GNAT (orig): real 6.0 user 5.8
GNAT (mod):  real 5.3 user 9.4

(the 'user' value, which is what time(1) reports, is apparently the
total CPU time, while the 'real' time is the elapsed time; this machine
has 2 cores, both it seems running at about 90% in the test).