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Subject: Re: [boost] [Fibers] Performance
From: Andreas Schäfer (gentryx_at_[hidden])
Date: 2014-01-16 08:50:31

On 13:27 Thu 16 Jan , Daniel James wrote:
> It isn't really user feedback, but feedback from a developer of
> similar functionality, which is something very different.

Yes and no. Usually someone who implemented similar code did just that
because he wanted to use it for himself. At least in an Open Source
environment. Thus the developer becomes the first user.

> Pedantically, the developer could also be a user of the library, but
> their main point of view is as a developer of such functionality, and
> their opinions are influenced by that. If they've put a lot of effort
> into something, then it's likely that they will overvalue it. Feedback
> from other developers is of course extremely useful, but the
> difference should be appreciated.

Let me try to rephrase that: said developer's point of view might be
biased, thus his arguments carry less weight. Is that what you're
saying? I'd then add to the discussion that his experience also makes
him a domain expert, which reinforces his authority. This road is
called "ad hominem" and doesn't lead anywhere. Lets get back to the

I, as a potential user of user-level threads a.k.a. fibers would only
use them if they allowed me to do something std::thread can't do for
me: many many, fine-grained threads, which relieve me of the burden of
having to adapt the decomposition of my compute problem. And this
again boils down to performance: if it's not going to be much faster,
why shouldn't I hand over the problem to the OS?

Being a library developer myself, I can assure you that performance is
not something you can easily bolt on afterwards. Rather, it has to be
built-in from the beginning. Otherwise you'll end up reimplementing
class after class. Just my 0.02€.


Andreas Schäfer
HPC and Grid Computing
Chair of Computer Science 3
Friedrich-Alexander-Universität Erlangen-Nürnberg, Germany
+49 9131 85-27910
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