Anyone know this paper?

gregory.menke at gsfc.nasa.gov gregory.menke at gsfc.nasa.gov
Wed Dec 15 19:40:06 UTC 2004


"Joel Sherrill <joel at OARcorp.com>" <joel.sherrill at OARcorp.com> writes:
 > gregory.menke at gsfc.nasa.gov wrote:
 > > "Joel Sherrill <joel at OARcorp.com>" <joel.sherrill at OARcorp.com> writes:
 > >  > http://vlsi.ee.duth.gr/amdrel/papers/date04.pdf
 > >  > 
 > >  > It is about dynmic memory allocation but I think they
 > >  > missed the boat on the RTEMS reference.  They appear
 > >  > to think that the RTEMS region/heap manager is based
 > >  > on a paper from 2001 which also used the term region.
 > >  > 
 > >  > The RTEMS heap design dates back to the earliest days
 > >  > of RTEMS and certainly predates a paper from 2001.
 > >  > 
 > > 
 > > I think they missed a lot of boats.  Its a pretty superficial
 > > treatment of memory allocation.  
 > 
 > Glad to know it just isn't me being stupid looking at it.
 > 
 > Can you even tell what algorithm/data structure they are proposing?

No, they seemed to spend their time vaporing away about network
traffic simulations and bitmap twiddling without presenting content-
or any examples of just how their algorithms help wireless and
multimedia applications- or any examples of said applications as
depoyed on embedded systems.  I got the vague impression that they
implemented a C++ layer on top of the OS heap functions to expose
their own memory allocation routines.  Then they claimed those big
percentage "gains" without defintions or data.  No doubt all will
become clear after they get funding for another round of
research.. lol ;)

 
 > > The cites here
 > > 
 > > http://www.informatik.uni-trier.de/~ley/db/indices/a-tree/b/Bonwick:Jeff.html
 > > 
 > > and also referenced
 > > 
 > > http://www.os-help.org/slab_allocators-542520-4686-a.html
 > > 
 > > treat the issue exhaustively, from userspace all the way down to
 > > scalability on SMP systems and cache-friendliness.  I think the people
 > > who did the paper you identified didn't do enough homework ahead of
 > > time.
 > 
 > Thanks.
 > 
 > I believe that there is no perfect algorithm for all real-time
 > embedded systems.  It would be great to be able to choose from
 > a variety of heap, CPU scheduling, disk scheduling and disk
 > caching algorithms based upon your application requirements.
 > 
 > It seems that no algorithm is perfect for every situation.

I agree.  That said, I'm a big fan of the slab concepts, I suppose
their downside is complexity & subtlety- its great for the user but
you have to put your software weenie hat on to understand what its
doing inside.

Gregm





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