Re: Data transfers from/to client

See our proposal for a WebGPUMappedMemory object in the similarly named
section of this doc
<https://docs.google.com/document/d/1HFzMMvDGHFtTgjNT0j-0SQ1fNU9R7woZ4JuNJdAXBjg/edit#heading=h.67ockbzesm2a>.
Basically it adds an objects that both pollable and supports promise-like
.then(callback).

On Wed, Jan 31, 2018 at 3:11 PM, Kai Ninomiya <kainino@google.com> wrote:

> More importantly than GC pressure, probably, is that shimming a C API on
> top of a Promise also inherently adds latency:
>
> let resolved = false;
> prom.then(() => { resolved = true; });
>
> raf(() => {
>   if (resolved) { ... }
> }
>
> So I think we'll need something non-promise-based for WASM anyway.
>
> On Wed, Jan 31, 2018 at 11:59 AM Kirill Dmitrenko <dmikis@yandex-team.ru>
> wrote:
>
>> When promise-based interface was proposed to the WebGL community,
>> there're some concerns about generating garbage (thread:
>> https://www.khronos.org/webgl/public-mailing-list/public_
>> webgl/1701/msg00001.php). However, maybe those concerns need some
>> qualitative analysis.
>>
>> 25.01.2018, 22:01, "Corentin Wallez" <cwallez@google.com>:
>> > On Wed, Jan 24, 2018 at 9:41 PM, Dzmitry Malyshau <
>> dmalyshau@mozilla.com> wrote:
>> >> === Shape of the API for data transfers ===
>> >>
>> >> One of the benefits of having poll-like interface (with fences or
>> something similar) is that it maps cleanly to C and thus maps perfectly to
>> WASM.
>> >> If we choose to have promises instead, how would they be accessible
>> from WASM? I don't see anything immediately related in the Host Bindings
>> Proposal.
>> >
>> > I assume you meant the WASM Host Bindings Proposal. I'm not sure about
>> direct bindings to promises but implementing a poll-like interface on top
>> of a promise interface would be easy to do with a shim. That said I agree
>> that it isn't clear how to make it work with minimal overhead in WASM.
>> Something important for Chrome is that the range of data that will be
>> accessed be explicit, because otherwise we would have to send all of the
>> buffer's content through the GPU command buffer. It's easy to see how a
>> promise interface could have explicit bounds, but it is less clear how to
>> do it with a poll API.
>>
>> --
>> Kirill Dmitrenko
>> Yandex Maps Team
>>
>>