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On Friday 05 November 2010 13:53:56 Darrin Thompson wrote:

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> Has anyone managed to get good results running valgrind vs. jackd or

> apps for it?

>=20

> My experience with Valgrind at work is you run it and it magically

> tells you the exact line of code where you have a serious bug, which

> is a good thing. But it has really high overhead. So I've been

> considering running it against say, Rosegarden, which I crashed

> repeatedly, but I'll beg off if someone has already been there and

> done that.

I did manage to run jackd (with the firewire backend) inside valgrind --

tool=3Dcallgrind. Its not suitable to get any audio output but it gives som=

e=20

numbers and showed me the main processing time is spent in the locks for=20

phase-locked-loop of the streaming-clock... Might be biased because the=20

streaming clocks of pc and device where running completely different becaus=

e of=20

the valgrind overhead. But experiments without valgrind and without the loc=

ks=20

gave reason that really a lot of time is spent waiting there. Unfortunately=

=20

the locks are needed as it will crash without them...
But its possible and does give some numbers and hints. The overhead of the=

=20

memcheck tool is lower then the overhead of callgrind btw.
Have fun,
Arnold
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