Re: [Valgrind-users] valgrind hang up on start up

[Milian W. <ma...@mi...>]

On Friday 17 August 2012 00:50:40 Umut Tabak wrote:
> Dear all,
> 
> I was trying to verify if there were memory leaks with my code until the
> point I could come, however at this point, I have a strange problem that
> valgrind on some problems hangs at start up.
> 
> Briefly on what I am doing: I am trying to read some numeric values from
> a file and set some arrays dynamically in my program, mathematically
> these numerical values are the values of a matrix. For this step I am
> using a C++ matrix library to set the matrix which is MTL4 in this case.
> 
> Running valgrind with relatively small input files goes smoothly and I
> can only see that I only have some still reachable errors. No loss
> reports, however if I increase the files sizes and try to use the same
> code with valgrind with a different input file, valgrind hangs on these
> large files.
> 
> I have found out a similar thread for this hanging problem, namely,
> 
> http://www.mail-archive.com/val...@li.../msg017
> 43.html
> 
> 
> I could not make it work with the default tool 'memcheck' on large
> problems, however if I use 'cachegrind' it works and outputs the results
> smoothly.
> 
> Any pointers on this topic are appreciated highly.

Are you sure they really "hang"? Remember that valgrind can easily slow down 
your app by a factor of 20-100. Suddenly your app doesn't run 1min but 
1h36min...

/me who tried to valgrind a scientific app which did a matrix diagonalizations 
for 1h (without valgrind)

Generally, do you have serious reasons to doubt that your app will work the 
same, no matter the size of the input? Otherwise your app might be just fine, 
if it works for smaller input sizes.
-- 
Milian Wolff
ma...@mi...
http://milianw.de