From: Jens Axboe > Sent: 03 May 2021 15:58 > > Had a report on writing to eventfd with io_uring is slower than it > should be, and it's the usual case of if a file type doesn't support > ->write_iter(), then io_uring cannot rely on IOCB_NOWAIT being honored > alongside O_NONBLOCK for whether or not this is a non-blocking write > attempt. That means io_uring will punt the operation to an io thread, > which will slow us down unnecessarily. > > Convert eventfd to using fops->write_iter() instead of fops->write(). Won't this have a measurable performance degradation on normal code that does write(event_fd, &one, 4); David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)
