Hi devs, Maybe you have also noticed some noise in the web about io_uring <https://kernel.dk/io_uring.pdf> - the better epoll.
Pros: - less syscalls - no copying of data between userland and kernel Cons: - it seems rather unstable to me. Many articles say that io_uring should be more stable since kernel v5.6.x but in my experience there are many changes in each kernel versions https://www.scylladb.com/2020/05/05/how-io_uring-and-ebpf-will-revolutionize-programming-in-linux/ is a good article explaining the benefits. Recently Netty project released 0.0.1-SNAPSHOT ( https://netty.io/news/2020/11/16/io_uring-0-0-1-Final.html) and 0.0.2-SNAPSHOT with some nice numbers: - epoll Speed: 80820 request/sec, 80820 response/sec Requests: 2424626 Responses: 2424625 - io_uring Speed: 267371 request/sec, 267370 response/sec Requests: 8021137 Responses: 8021128 I've tried it with my HTTP2 comparison tests (https://martin-grigorov.medium.com/comparing-the-performance-of-several-http2-web-servers-fb5f3787532a) and the results were better but not so dramatic: - epoll -- x86_64: 24688 reqs/sec -- aarch64: 25344 - uring -- x86_64: 26731 -- aarch64: 28443 So I thought: What about introducing a Uring Protocol/Connector ?! Since Netty uses JNI to talk to io_uring C APIs it should look something like the AprConnector. But soon after I realized that it would be much more reusable if implemented as java.nio.channels.spi.SelectorProvider. This way any project (not just Tomcat) can make use of it. Here I wanted to poll what other devs think about this idea ? Does that sound interesting to you ? Or we should leave it to the JDK developers to do it for JDK XY (I guess this could be as early as Java 18 since 17 will be a LTS and most probably the current epoll based impl won't be replaced so soon). I don't suggest to put it in Tomcat's code, so the dependency on JNI should not be considered as a stopper. I have some very early attempts implementing it with Netty's JNI code and with Java Panama's jextract, but I've faced issues with both. Please encourage/discourage me to continue digging in this! :-) Regards, Martin
