Re: [boost] [afio] Formal review of Boost.AFIO

On 28.08.2015 07:47, Thomas Heller wrote:

Now, on to your example about a 100 parallel reads, so let's encapsulate it a bit to concentrate on the important part:

future<void> read_items(handle const & h) { vector> reads; reads.reserve(100); for(std::size_t i = 0; i != 100; ++i) { reads.push_back(async_read(h, 4096, i * 4096)); } // handle reads in some form ... for simplicity, just wait on all //of them ... return when_all(std::move(reads)); }

No continuations, cool, eh?

How would this affect performance? From what I can gather, with the current AFIO I should be able to issue the entire batch of async read/write's to copy a file, using a single buffer (by making a dependency chain using the preconditions). In your API, won't those read/write calls have to take the trip into user land for each step? Sorry if I misunderstood something and this is just noise. Cheers - Asbjørn