http2 POST delay

[icing]

When using curl --form file=@xxx .... against my server, there is a 1-2 second delay before curl actually sends the request body. Using the nghttp2 client does not show this behavior.

Might it be that this is some effect of Expect header handling, that just will not trigger in HTTP/2?

[bagder]

Thanks. Does it show with a mere -d "fooo" (instead lf --form) as well ? I've not done a lot of posts over HTTP/2 so it is probably something like that lingering...

[bagder]

Just pushed commit ef1c3b4 which I believe fixes this.

[icing]

Yes, that fixes it for the "h2" case (TLS). The "h2c" case, where no upgrade is triggered because of request content, it still seems unchanged slow. I see no delay, but the upload takes longer than in the TLS case. Some fallback code when nghttp2 does not kick in perhaps?

[bagder]

Isn't that just the ordinary Expect: 100-continue delay then? Try with -H Expect: and see if it changes anything!

[icing]

As you can see below, the initial wait is gone in all cases, but the upload itself shows poor performance when --http2 is given. ('w. Expect' means -H Expect:)

Timings with curl from github (this morning):

curl https://test.example.org:12346/upload.py: 100k file upload default...
        0.22 real         0.01 user         0.00 sys
        0.03 real         0.01 user         0.00 sys
curl https://test.example.org:12346/upload.py: 100k file upload via http/2...
        0.22 real         0.01 user         0.00 sys
        0.03 real         0.01 user         0.00 sys
curl https://test.example.org:12346/upload.py: 100k file upload default w. Expect...
        0.22 real         0.01 user         0.00 sys
        0.03 real         0.01 user         0.00 sys
curl https://test.example.org:12346/upload.py: 100k file upload via http/2 w. Expect...
        0.22 real         0.01 user         0.00 sys
        0.03 real         0.01 user         0.00 sys
curl http://test.example.org:12345/upload.py: 100k file upload default...
        0.07 real         0.00 user         0.00 sys
        0.01 real         0.00 user         0.00 sys
curl http://test.example.org:12345/upload.py: 100k file upload via http/2...
        7.24 real         0.00 user         0.00 sys
        0.01 real         0.00 user         0.00 sys
curl http://test.example.org:12345/upload.py: 100k file upload default w. Expect...
        0.07 real         0.00 user         0.00 sys
        0.01 real         0.00 user         0.00 sys
curl http://test.example.org:12345/upload.py: 100k file upload via http/2 w. Expect...
        7.24 real         0.00 user         0.00 sys
        0.19 real         0.00 user         0.00 sys

Timings with curl 7.41.0:

curl https://test.example.org:12346/upload.py: 100k file upload default...
        0.09 real         0.01 user         0.00 sys
        0.03 real         0.01 user         0.00 sys
curl https://test.example.org:12346/upload.py: 100k file upload via http/2...
        4.05 real         0.01 user         0.00 sys
        0.03 real         0.01 user         0.00 sys
curl https://test.example.org:12346/upload.py: 100k file upload default w. Expect...
        0.09 real         0.01 user         0.00 sys
        0.03 real         0.01 user         0.00 sys
curl https://test.example.org:12346/upload.py: 100k file upload via http/2 w. Expect...
        0.22 real         0.01 user         0.00 sys
        0.03 real         0.01 user         0.00 sys
curl http://test.example.org:12345/upload.py: 100k file upload default...
        0.07 real         0.00 user         0.00 sys
        0.01 real         0.00 user         0.00 sys
curl http://test.example.org:12345/upload.py: 100k file upload via http/2...
        8.05 real         0.00 user         0.00 sys
        0.01 real         0.00 user         0.00 sys
curl http://test.example.org:12345/upload.py: 100k file upload default w. Expect...
        0.07 real         0.00 user         0.00 sys
        0.01 real         0.00 user         0.00 sys
curl http://test.example.org:12345/upload.py: 100k file upload via http/2 w. Expect...
        7.24 real         0.00 user         0.00 sys
        0.01 real         0.00 user         0.00 sys.

[bagder]

All right. Thanks a bunch for all the details. I guess I need to roll up my sleeves and check it out closer.

[bagder]

commit abfab17 fixes this problem for me at least.

Thanks again!

[icing]

Yep. Works flawlessly. Thanks!