proposal: net/http: a configurable write buffer size for the http server

[oddmario]

Proposal Details

The Go http.Server currently uses a hard coded 4 KB buffer for the response writer. In some cases, developers of certain applications may prefer increasing the default 4 KB for higher throughput and better performance.

This has been discussed previously at #13870 and at https://groups.google.com/g/golang-dev/c/OuFtcKEyGrg

The performance with the default 4 KB buffer size:

go test -test.bench=".*" -benchmem -benchtime=5s
BenchmarkBigWrite-4   100000         79756 ns/op       37929 B/op         72 allocs/op
ok      mytest/httpbuf  8.857s
BenchmarkBigWrite-4   100000         78570 ns/op       37948 B/op         72 allocs/op
ok      mytest/httpbuf  8.665s
BenchmarkBigWrite-4   100000         79072 ns/op       37876 B/op         72 allocs/op
ok      mytest/httpbuf  8.718s

The performance with a 10 KB buffer size:

go test -test.bench=".*" -benchmem -benchtime=5s
BenchmarkBigWrite-4   100000         69645 ns/op       39890 B/op         73 allocs/op
ok      mytest/httpbuf  7.692s
BenchmarkBigWrite-4   100000         69816 ns/op       39961 B/op         73 allocs/op
ok      mytest/httpbuf  7.702s
BenchmarkBigWrite-4   100000         67768 ns/op       39856 B/op         73 allocs/op
ok      mytest/httpbuf  7.516s

Proposed solution:

Add a configurable WriteBufferSize option to the http.Server struct, which then the HTTP server will use when set instead of the hard coded 4 << 10 value.

I have recently opened a pull request that possibly addresses this #68143

[gabyhelp]

Similar Issues

• net/http: make ResponseWriter buffer size configurable #7467
• net/http: make the http server con write buffer size configurable #68143
• net/http: make the http server con write buffer size configurable #68142
• net/http: Can the http.Server add set read/write buffer size? #13870
• net/http: consider adding configurable buffer sizes to Transport #22618
• net/http: server sets TCPConn writebuf through ConnContext hook will block the send of a big response body #50795

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[seankhliao]

Let's just keep the conversation in #13870

[gopherbot]

Change https://go.dev/cl/594196 mentions this issue: net/http: make the http server con write buffer size configurable