Re: RAM consumption when working with the gcc repo

From: Marco Costalba <mcostalba@gmail.com>
Date: Dec 8, 2007, 19:12 UTC
Message-ID: <e5bfff550712081112xf34eb1cua95da3f9397030f0@mail.gmail.com>
In-Reply-To: <Pine.LNX.4.64.0712081153500.27959@racer.site>

On Dec 8, 2007 12:54 PM, Johannes Schindelin <Johannes.Schindelin@gmx.de> wrote:

Show 10 quoted lines

> >
> > BTW does exist a tool to profile memory consumption by each source level
> > struct / vector/ or any other data container?
> >
> > Valgrind checks mainly memory leaks, callgrind gives profiling
> > information in terms of call graphs and times/cycles consumed by each
> > function.
>
> Have you looked at Massif (also part of Valgrind)?
>

Only very quickly, so probably I've missed something, but anyway that's my comment on Massiv:

- Interesting output is in html format, graph is nice but gives very
general info.

- The tool mainly tracks who called malloc and friends also going back
in the stack frame (in my box if I try to set stack deep at 4 instead
of default 3 program crashes)

- Does not seem to give information regarding the structures where
memory is allocated, only the function names that allocate directly or
indirectly the memory. Nothing like

struct my_data has 34.256 instantiations struct stuff has 2.456 instantiations

- Relation between memory and time of allocation is IMHO a little bit
confusing, it's like a parameter obtained from multipling allocated
bytes x time, not very useful.

- Regarding the previous point, it seems missing a way to
trigger/snapshotting the memory map in terms of source level
structures used by the application in a given time, triggable through
code.

Just to be clear, the much better callgrind tool allows to insert in the code the macros

CALLGRIND_START_INSTRUMENTATION and CALLGRIND_STOP_INSTRUMENTATION

that start/stop recording of events in the code ranges specified by the developer. What it seems to be missing in massif it's a macro like

MASSIV_SNAPSHOT_MEM_MAP

to be used _where_ developer needs and that gives information on heap allocation in terms of source level entities that *use* that memory, not low level addresses or allocator functions.

Thanks Marco