Searched nginx source. Seems like it's using aio_read() aio_write() ./src/os/unix/ngx_file_aio_read.c API's doc https://man7.org/linux/man-pages/man3/aio_read

Searched nginx source. Seems like it's using aio_read() aio_write() ./src/os/unix/ngx_file_aio_read.c API's doc https://man7.org/linux/man-pages/man3/aio_read.3.html https://man7.org/linux/man-pages/man3/aio_read.3.html Even though the source is there don't mean it's compiled or used though. Might or might not be. No idea about the details.