Re: [boost] [Beast] Questions Before Review

Subject: Re: [boost] [Beast] Questions Before Review
From: Vinnie Falco (vinnie.falco_at_[hidden])
Date: 2017-06-26 02:28:23

On Sun, Jun 25, 2017 at 7:12 PM, Niall Douglas via Boost
<boost_at_[hidden]> wrote:
> Most users I should imagine would therefore build
> scatter-gather lists on the stack as they'll be thrown away immediately,
> indeed I usually feed it curly braced initializer_lists personally,

Thus imposing limitation on the size of the buffer sequence.

> I think you are going to have to back up your claim that memory
> copying all incoming data is faster rather than being bad implementation
> techniques with discontinuous storage

I'll let Kazuho back it up for me since I use his ideas:
https://github.com/h2o/picohttpparser

Here's the slide show explaining the techniques:
https://www.slideshare.net/kazuho/h2o-20141103pptx

And here is an example of the optimizations possible with linear
buffers, which I plan to directly incorporate into Beast in the near
future:
https://github.com/h2o/picohttpparser/blob/2a16b2365ba30b13c218d15ed9991576358a6337/picohttpparser.c#L110

Of course if you think you can do better I would love to see your
working parser that operates on multiple discontiguous high quality
ring buffered page aligned DMA friendly storage iterators so that I
might compare the performance. The good news is that you can do so
while leveraging Beast's message model to produce objects that people
using Beast already understand. Except that you'll be producing them
much, much faster (which is a win-win for everyone).