I wrote a previous update about my work on multiplexing in curl. This is a follow-up to describe the status as of today.

I’ve successfully used the http2-upload.c code to upload 600 parallel streams to the test server and they were all sent off fine and the responses received were stored fine. MAX_CONCURRENT_STREAMS on the server was set to 100.

This is using curl git master as of right now (thus scheduled for inclusion in the pending curl 7.43.0 release).  I’m not celebrating just yet, but it is looking pretty good. I’ll continue testing.

Commit b0143a2a3 was crucial for this, as I realized we didn’t store and use the read callback in the easy handle but in the connection struct which is completely wrong when many easy handles are using the same connection! I don’t recall the exact reason why I put the data in that struct (I went back and read the commit messages etc) but I think this setup is correct conceptually and code-wise, so if this leads to some side-effects I think we need to just fix it.

Next up: more testing, and then taking on the concept of server push to make libcurl able to support it. It will certainly be a subject for future blog posts…