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)```

[jfgiorgi]

with go 1.23.2

batch #0:
 Id| Read speed| Write speed| Time| Bytes read| Bytes written|command
 #1|  12.2 Gbps|       0 bps| 8.00|    12.2 GB|           0 B|get -http1.1 https://[::1]:46075/20g (IPv6 - 0.151 ms - HTTP/1.1 - TLS 1.3)

batch #1:
 Id| Read speed| Write speed| Time| Bytes read| Bytes written|command
 #3|   9.3 Gbps|       0 bps| 8.00|     9.3 GB|           0 B|get -http2 https://[::1]:35761/20g (IPv6 - 0.202 ms - HTTP/2.0 - TLS 1.3)

batch #2:
 Id| Read speed| Write speed| Time| Bytes read| Bytes written|command
 #5|   4.1 Gbps|       0 bps| 8.00|     4.1 GB|           0 B|get -http3 https://[::1]:49088/20g (IPv6 - 0.163 ms - HTTP/3.0 - TLS 1.3)

[jfgiorgi]

march 2025, with go 1.24.1

batch #0:
              Id| Read speed| Write speed| Time| Bytes read| Bytes written|command
 HTTPS/1.1 GET 1|  11.8 Gbps|       0 bps| 8.00|    11.8 GB|           0 B|get -http1.1 https://[::1]:35619/20g - 1/1(IPv6 - 0.136 ms - HTTP/1.1 - TLS 1.3)

batch #1:
            Id| Read speed| Write speed| Time| Bytes read| Bytes written|command
 HTTPS/2 GET 2|   6.5 Gbps|       0 bps| 8.00|     6.5 GB|           0 B|get -http2 https://[::1]:37649/20g - 1/1(IPv6 - 0.106 ms - HTTP/2.0 - TLS 1.3)

batch #2:
            Id| Read speed| Write speed| Time| Bytes read| Bytes written|command
 HTTPS/3 GET 3|   4.5 Gbps|       0 bps| 8.00|     4.5 GB|           0 B|get -http3 https://[::1]:45108/20g - 1/1(IPv6 - 0.183 ms - HTTP/3.0 - TLS 1.3)

[jfgiorgi]

July 2026, with go 1.26.3

batch #0:
┌────────────┬────────────┬────────────────────────────────────────────────────────────────────────────────┐
│HTTPS/1.1   │12.0 Gbps   │get -http1.1 https://[::1]:39517/20g - 1/1(IPv6 - 0.112 ms - HTTP/1.1 - TLS 1.3)│
└────────────┴────────────┴────────────────────────────────────────────────────────────────────────────────┘
batch #1:
┌─────────────┬───────────────────────────────────────────────────────────────────────────────────────────┐
│HTTPS/2      │8.3 Gbps     │get -http2 https://[::1]:41811/20g - 1/1(IPv6 - 0.75 ms - HTTP/2.0 - TLS 1.3)│
└─────────────┴─────────────┴─────────────────────────────────────────────────────────────────────────────┘
batch #2:
┌─────────────┬─────────────┬─────────────────────────────────────────────────────────────────────────────┐
│HTTPS/3      │4.9 Gbps     │get -http3 https://[::1]:35697/20g - 1/1(IPv6 - 0.30 ms - HTTP/3.0 - TLS 1.3)│
└─────────────┴─────────────┴─────────────────────────────────────────────────────────────────────────────┘