I agree that there wasn't any notable "copy" I/O performance increase, but the CPU cycles and memory I/O are significantly reduced.
So while most modern machines' have CPUs and memory buses that have plenty of room for inefficient user-space copies on a quiescent machine, it's the efficiency I was looking for. I think on a heavily loaded machine or with a serious disk subsystem the difference would be more apparent to the user. /kristofer > -----Original Message----- > From: Jim Meyering [mailto:[EMAIL PROTECTED] > Sent: Saturday, April 05, 2003 1:29 PM > To: Spinka, Kristofer > Cc: [EMAIL PROTECTED] > Subject: Re: Patch to eliminate user space memory copying in 'cp' > > Jim Meyering <[EMAIL PROTECTED]> wrote: > > "Spinka, Kristofer" <[EMAIL PROTECTED]> wrote: > >> You will have to incorporate the check for sendfile, but otherwise > >> this patch should avoid the most common kernel<->user space read/write > >> transitions. > > > > Thank you for that patch. It looks like a fine optimization. > > > > I'll work on integrating it after coreutils-5.0. > > After a few simple tests, I don't see any performance > benefit to using sendfile. Do you have evidence that > using sendfile is worthwhile? _______________________________________________ Bug-fileutils mailing list [EMAIL PROTECTED] http://mail.gnu.org/mailman/listinfo/bug-fileutils
