[mythtv-users] `Mythbackend leaks memory` continued

Nick Rout nick.rout at gmail.com
Sun Jun 22 19:44:24 UTC 2008

On Mon, Jun 23, 2008 at 7:03 AM, Ray Lischner <linux at tempest-sw.com> wrote:
> On Sunday 22 June 2008 08:32 am, Udo van den Heuvel wrote:
>> PS: I am willing to try valgrind for a limited time; I fera the
>> machine will be slowed down even below normal usable speeds but if we
>> could catch a leak within say 24 hours...
> Valgrind is a useful tool, but not the right tool in this situation.
> First, we need to ascertain whether the leak exists. Valgrind is a
> developer's tool to help locate the source of the leak.
> Most of us are running mythbackend for days, weeks, or months, without
> any memory problems, which demonstrates that in normal code paths,
> there are no leaks. There might be leaks on other code paths. The
> difficulty is identifying those code paths.
> Whoever is experiencing mythbackend running out of memory needs to:
> 1. Verify that mythbackend truly is running out of memory. Watch the
> virtual memory size (VIRT) and the resident set size (RES) in top.
> Watch VIRT over time. Does it increase forever? Does it sometimes go
> down. If so, when? It isn't always easy for a user to find a memory
> leak, but if the backend runs long enough, and the leak is real, the
> numbers will show it.
> 2. Verify that the behavior is repeatable. Reboot the backend and try it
> again.
> 3. Determine what about that user's environment is different, unusual,
> or unique. Post details so others can try similar setups. If no one
> else can reproduce the problem, there is no hope of fixing it. This is
> the hard part, but is absolutely crucial.
> I'm not a myth developer, but I am a software developer who has used
> valgrind a lot, including on projects bigger than myth.

I suspect this is quite frustrating for Udo. He recently started a
long thread in which he was criticised for not running valgrind to
support a bug ticket that he filed (and I joined in briefly).


Now you are saying valgrind is the wrong tool. I feel a bit sorry for
Udo if that is the case.

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