Re: RFD: The Future of Memory Management in Wireshark

[Sébastien Tandel <sebastien.tandel () gmail com>]

On Wed, Oct 24, 2012 at 1:10 AM, Guy Harris <guy () alum mit edu> wrote:

> On Oct 18, 2012, at 6:01 PM, Evan Huus <eapache () gmail com> wrote:
>
> > I have linked a tarball [2] containing the following files:
> > - wmem_allocator.h - the definition of the allocator interface
> > - wmem_allocator_glib.* - a simple implementation of the allocator
> > interface backed by g_malloc and a singly-linked list.
>
> Presumably an implementation of the allocator could, instead of calling a
> lower-level memory allocator (malloc(), g_malloc(), etc.) for each
> allocation call, allocate larger chunks and parcel out memory from the
> larger chunks (as the current emem allocator does), if that ends up saving
> enough CPU, by making fewer allocate and free calls to the underlying
> memory allocator, so as to make it worth whatever wasted memory we have at
> the ends of chunks?
One step further, instead of mempools, I think wireshark could have great
interest in implementing slabs (slab
allocator<http://www.parrot.org/sites/www.parrot.org/files/vmem.pdf>).
Slabs had initially been designed for kernel with several advantages over
traditional allocators in terms of resources needed to allocate (CPU),
(external / internal) fragmentation and also cache friendliness (most of
the traditional allocators don't care). I've attached some slides about a
high-level description of slab.

Since then, another
paper<http://www.parrot.org/sites/www.parrot.org/files/vmem.pdf>has
been written showing some improvements and what it took to write a
slab
for user-space (libumem). There is another well-known exampel out there,
called memcache, that implements its own version (and could be a good
intial point for wireshark implementation, who knows? :))


Regards,
Sebastien Tandel


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