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List:       kde-bugs-dist
Subject:    [Bug 109861] valgrind freezes on start/exit of valgrind itself
From:       Tom Hughes <tom () compton ! nu>
Date:       2005-07-31 8:37:52
Message-ID: 20050731083752.4194.qmail () ktown ! kde ! org
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http://bugs.kde.org/show_bug.cgi?id=109861         




------- Additional Comments From tom compton nu  2005-07-31 10:37 -------
Ah, I hadn't realised you were talking about a PIE build... There is a reason we \
disabled that by default, namely that it doesn't work very well ;-)

The problem comes when valgrind does the big bang shadow memory allocation - it tries \
to map the entire shadow memory area up front and then later on it just changes the \
protection on the pages it wants to use.  

It it clearly the kernel causing the problem - on your machine it takes 109 seconds \
to map the shadow memory. On my FC4 box (running kernel  2.6.12-1.1398_FC4smp) it \
takes just 0.7 seconds to do the same mapping in a PIE build.

The mapping is large (about 67Tb if I've done my maths right).


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