On Sun, 18 Oct 2009, Greg Lewis wrote: > G'day Michael, > > On Fri, Oct 16, 2009 at 04:55:08PM -0700, Michael Allman wrote: >> Can someone explain why we aren't using sendfile() in the transferTo0 call >> for the case of a file transfer to a network socket in FileChannelImpl.c? >> >> Also, my understanding is that if this call cannot do a sendfile(), it >> should return IOS_UNSUPPORTED_CASE. This will tell the caller to do a >> loop-based transfer (see sun.nio.ch.FileChannelImpl.transferTo(), line >> 531). > > I think the reason is basically historical. I don't recall there being > a fallback when we originally ported the NIO code, so sendfile() didn't > make sense since it only transferred to network sockets. > > Before switching I'd want to see what sort of affect that had performance > wise on the case of transferring to a file descriptor.
Hi Greg, >From a Darwin perspective, it would be awful nice if Apple open-sourced their implementation. I recall finding a while back that Apple's Java runtime used sendfile() by using DTrace. Thanks for the info. If I had a knowledge of C++ and system programming on BSD platforms, I'd be happy to submit a patch. Cheers, Michael
