HTTP/2 performance issue

[jfgiorgi]

bug in the golang net/http implementation of HTTP/2
see golang/go#47840

workaround/proposed fixes:

• apply https://go-review.googlesource.com/c/net/+/362834 in your own Go copy. Then set a big enough MaxFrameSize in a http2.Transport (so this isn't automatic)
• tweak http2bufWriterPoolBufferSize in http2.go ?

In both case you might need to rebuild the whole net/http lib because of bundle trick used to merge http2 into net/http.

mid-term solution: Investigate using 3rd party HTTP/2 implementation (libcurl ?) or abandon Go and use C++ or Rust ?

[jfgiorgi]

update on nov 2023: progress were made by the Go team. the ratio is now ~2x, down from ~5x.

[jfgiorgi]

with go1.21.3:

./nspeed b h1sg then b h2g then b h3g

batch #0:
 Id| Read speed| Write speed| Time| Bytes read| Bytes written|command
 #1|  11.7 Gbps|       0 bps| 8.00|    11.7 GB|           0 B|get -http1.1 https://[::1]:45025/20g (IPv6 - 0.250 ms - HTTP/1.1 - TLS 1.3)

batch #1:
 Id| Read speed| Write speed| Time| Bytes read| Bytes written|command
 #3|   8.5 Gbps|       0 bps| 8.00|     8.5 GB|           0 B|get -http2 https://[::1]:45939/20g (IPv6 - 0.113 ms - HTTP/2.0 - TLS 1.3)

batch #2:
 Id| Read speed| Write speed| Time| Bytes read| Bytes written|command
 #5|   3.7 Gbps|       0 bps| 8.00|     3.7 GB|           0 B|get -http3 https://[::1]:33659/20g (IPv6 - 0.220 ms - HTTP/3.0 - TLS 1.3)```