4 ms·

Thanks for the explanation. If it works like you describe it seems to be a reasonable way to obtain streaming behavior. Will take a look at it if I find some ti

Thanks for the explanation. If it works like you describe it seems to be a reasonable way to obtain streaming behavior. Will take a look at it if I find some time. Regarding backpressure and HTTP/2: You get some different kind of backpressure behavior with your approach (application level flow control) and the grpc approach (transport level flow control). Let's say you have 2 functions which are called in parallel. For one the arguments are very big (let's say 100kB), for the other one they are small (some bytes). With HTTP/2 and transport level flow control the small function could get the bandwidth as the big one, which means more requests/s for the small function. With pure application level flow control the small function needs to wait until the big one is fully sent before it can be put on the wire. Which means if I have 2 tasks that execute concurrently and look like A: while (true) { await callBigFunction(); } B: while (true) { await callSmallFunction(); } then with grpc I get more calls for B and without Cap'N'Proto I get the same for both (correct me if I'm wrong). I don't think it's a huge disadvantage in practice, because if you have large data chunks you should probably design your API different - and if you want realtime behavior then probably both protocols are not optimal. But it's still something to keep in mind.

kentonv 10y ago
You can achieve what you describe under my scheme by counting the total size of the parameters of all calls in flight rather than just counting the calls. This is what sophisticated systems are doing in practice and is what I plan to do when incorporating the pattern into the library.
- Matthias247 10y ago
  The described approach sounds very reasonable! Besides building more support in the library it would maybe also be very worthwhile to have these patterns described together with examples on the website. E.g. how to achieve callback interfaces which don't user another connection, server->client streaming, etc. For me as a potential user information about these kind of features would make Cap'n'Proto immediately look more interesting. When I look at the website I only see Promise Pipelining described as a main feature - which is novel for sure, but not something that attracts my interest if I look for the other features we discussed about.

kentonv 10y ago

You can achieve what you describe under my scheme by counting the total size of the parameters of all calls in flight rather than just counting the calls. This is what sophisticated systems are doing in practice and is what I plan to do when incorporating the pattern into the library.

Matthias247 10y ago
The described approach sounds very reasonable! Besides building more support in the library it would maybe also be very worthwhile to have these patterns described together with examples on the website. E.g. how to achieve callback interfaces which don't user another connection, server->client streaming, etc. For me as a potential user information about these kind of features would make Cap'n'Proto immediately look more interesting. When I look at the website I only see Promise Pipelining described as a main feature - which is novel for sure, but not something that attracts my interest if I look for the other features we discussed about.