Hi, I am running some load tests on Tomcat and I've noticed that when HTTP2 is enabled the throughput drops considerably.
Here are the steps to reproduce: 1) Enable HTTP2, e.g. by commenting out this connector: https://github.com/apache/tomcat/blob/d381d87005fa89d1f19d9091c0954f317c135d9d/conf/server.xml#L103-L112 2) Download Vegeta load tool from: https://github.com/tsenart/vegeta/releases/ 3) Run the load tests: 3.1) HTTP/1.1 echo -e '{"method": "GET", "url": "http://localhost:8080/examples/"}' | vegeta attack -format=json -rate=0 -max-workers=1000 -duration=10s | vegeta encode > /tmp/http1.json; and vegeta report -type=json /tmp/http1.json | jq . 3.2) HTTP2 echo -e '{"method": "GET", "url": "https://localhost:8443/examples/"}' | vegeta attack -format=json -http2 -rate=0 -max-workers=1000 -insecure -duration=10s | vegeta encode > /tmp/http2.json; and vegeta report -type=json /tmp/http2.json | jq . As explained at https://github.com/tsenart/vegeta#-rate -rate=0 means that Vegeta will try to send as many requests as possible with the configured number of workers. I use '-insecure' because I use self-signed certificate. On my machine I get around 14-15K reqs/sec for HTTP1.1 with only responses with code=200 . But for HTTP2 Tomcat starts returning such kind of errors: "errors": [ "Get \"https://localhost:8443/examples/\": http2: server sent GOAWAY and closed the connection; LastStreamID=9259, ErrCode=PROTOCOL_ERROR, debug=\"Stream [9,151] has been closed for some time\"", "http2: server sent GOAWAY and closed the connection; LastStreamID=9259, ErrCode=PROTOCOL_ERROR, debug=\"Stream [9,151] has been closed for some time\"", "Get \"https://localhost:8443/examples/\": http2: server sent GOAWAY and closed the connection; LastStreamID=239, ErrCode=PROTOCOL_ERROR, debug=\"Stream [49] has been closed for some time\"" ] when I ask for more than 2000 reqs/sec, i.e. -rate=2000/1s All the access logs look like: 127.0.0.1 - - [15/Sep/2020:13:59:24 +0300] "GET /examples/ HTTP/2.0" 200 1126 127.0.0.1 - - [15/Sep/2020:13:59:24 +0300] "GET /examples/ HTTP/2.0" 200 1126 127.0.0.1 - - [15/Sep/2020:13:59:24 +0300] "GET /examples/ HTTP/2.0" 200 1126 127.0.0.1 - - [15/Sep/2020:13:59:24 +0300] "GET /examples/ HTTP/2.0" 200 1126 127.0.0.1 - - [15/Sep/2020:13:59:24 +0300] "GET /examples/ HTTP/2.0" 200 1126 127.0.0.1 - - [15/Sep/2020:13:59:24 +0300] "GET /examples/ HTTP/2.0" 200 1126 i.e. there are no error codes, just 200. Vegeta reports the error with status code = 0. I think this just means that it didn't get a proper HTTP response but just TCP error. There are no errors in catalina.out. Are there any settings I can tune to get better throughput with HTTP2 ? Tomcat 10.0.0-M8. Regards, Martin
