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Subject: Re: [boost] Proposal: Monotonic Containers
From: Ross Levine (ross.levine_at_[hidden])
Date: 2009-06-17 13:16:48

Agreed. Christian hasn't posted any results for pool_allocator and
fast_pool_allocator either.

I am also tired of the complete lack of understanding of what is and is not
defined in the standard. Originally I wanted to help with this idea, but the
idea isn't very mature and I can't support it anymore. This discussion has
officially become too frustrating to participate in for me.

On Wed, Jun 17, 2009 at 12:15 PM, Simonson, Lucanus J <
lucanus.j.simonson_at_[hidden]> wrote:

> Christian Schladetsch wrote:
> > Hi Frank,
> >
> > I do think your allocator could be useful, it just needs to be paired
> > with
> >> containers that it is guaranteed to work with.
> >
> >
> > I empathise, so I added monotonic::static_storage<> and
> > monotonic::static_shared_storage<>. See
> >
> > I then re-ran test_map_list(), see
> >
> > MSVC /O2:
> > count mono std mono_static mono/std mono_static/std
> > 1100 1.831 1.717 4.398 0.416326% 0.390405%
> >
> > And for GCC 4.3.3 -O4:
> > 1100 1.2 1.18 1.86 0.645161% 0.634409%
> >
> First of all, speedup should be old/new, not new/old. Second, I looked at
> your benchmark code to confirm and your mono, std and mono_static numbers
> above are apparently elapsed time in (I assume) seconds. The problem with
> this is that mono and mono_static have higher elapsed time in all cases in
> the data you present than std, but you somehow get this mono/std fraction
> that is less than one and tack a % sign on it for no reason that I can see.
> I find such things annoying, but furthermore these indicate a lack of
> background, experience and attention to detail that calls the quality of
> your work in general into question. Have you ever published a technical
> academic paper?
> Finally, it is clear that GCC and MSVC are using completely different
> allocators since you get very different results when comparing. Instead of
> comparing against whatever you get with default switches in two major
> compilers, why don't you go out and do some research into 3rd party
> allocators such as are provided by google and TBB which are known to be
> *better* than the std allocator in gcc and compare against those.
> I think you are learning a lot from all of this, but if I think writing
> your own allocator to meet the need for a faster allocator might be the
> wrong way to solve your performance problem. You should be looking for a
> freely available alternative allocator that has the features you want, and
> only after you rule out that you can get one for free should you write your
> own.
> I've thought some more about your application domain, and programming for
> XBox and Cell is a special kind of hell where cache coherency really is
> king, since you have to do it manually. I can sympathize with your desire
> to allocate everything on the stack in such an architecture. Perhaps you
> are solving a problem that is specific to your situation and not really
> general to C++ programming at large.
> Regards,
> Luke
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