Re: [Qemu-devel] valgrind functionality in qemu?

[Johannes Schindelin]

Hi,

On Sat, 20 Nov 2004, Marc E. Fiuczynski wrote:

> Just curious whether anyone has thought about putting things like the
> memory profiling, thread debugging, etc. features of valgrind
> (http://valgrind.kde.org/) into qemu?!

Yes, I for one have.

The upside of it would be the flexibility you have: you can let QEmu do
virtually everything, and you can even make very complex "watch points"
or "invariant conditions".

The downside is execution speed. Valgrind does not have to deal with a
complete translation, but only the translation of memory accesses. Thus,
valgrind should be much faster all the time. Also note that the memory
usage would be much higher with QEmu, which gets worse especially with
growing code size.

It would also be difficult to find the reference to the source code,
because there is no support for working with the debug information in the
code in QEmu that I know of. If you want to debug the Linux kernel, you
need to hack the "-kernel" loading code for that.

I don't want to discourage you, but be warned: while it sure would be
useful, and also feasible, you will have to put in a lot of work and
thought into that project.

Ciao,
Dscho