[Ns-developers] Idiotic question about the callbacks

Gustavo Carneiro gjcarneiro at gmail.com
Sun Mar 18 04:27:45 PDT 2012


On Sun, Feb 26, 2012 at 02:27, John Abraham <jabraham3 at mail.gatech.edu>wrote:

> The valgrind errors seem to vary both intra-OS (Ubuntu 10 vs 11) and
> inter-OS (Ubuntu vs Fedora), which sometimes made me question the use of
> valgrind. Still it used by a lot of people.
>
> Throughout last year while being involved with  various ns-3 builds, I
> have seen that , now, only Fedora systems can completely "PASS" ns-3 passed
> through valgrind,  in this generation of gcc.
> I also raised the issue with Tom, that we need to ensure that at least
> Fedora systems can validate ns-3 with valgrind or pretty soon we will have
> no releases that can pass valgrind.
> As, very often, ns-3 is used for simulations that last for hours even
> days, valgrind checks for leaks becomes crucial.
>
> Ubuntu systems report valgrind errors for ns-3 in a variety of places
> especially in third-party libraries like libpixman or libselinux. The
> errors range from leaks to unreachable code to still reachable memory or
> unconditional jumps. And the Mac, I don't even want to go there. OSX-lion
> is quite a challenge.
>
> I understand the pain in using valgrind. And I would also admit, I don't
> have the ability to narrow down the root-cause of the valgrind errors. I've
> spent hours on it. Very cryptic and one can only guess.
>

I think we have to be able to distinguish between valgrind errors in ns-3
code itself and valgrind errors in 3rd party libraries.  The former I think
are important to detect and fix, the latter are just noise and out of our
control.

To avoid valgrind errors in 3rd party libraries, we might want to build
ns-3 without linking to those libraries.  Gtk+, for instance, is linked to
by default unless it is not found.  We may need to add a --disable-gtk
option.  Same for the other libraries.

The remaining valgrind errors probably denote bugs.  Should we not fix
these bugs?

-- 
Gustavo J. A. M. Carneiro
INESC Porto, UTM, WiN, http://win.inescporto.pt/gjc
"The universe is always one step beyond logic." -- Frank Herbert



More information about the Ns-developers mailing list