Replacing Atime With Relatime in the Kernel

eldavojohn writes "Our friend Jeremy at the Kernal Trap has dug up some interesting criticism of atime from Linus Torvalds. As Linus submitted patches to improve relatime he noted: 'I cannot over-emphasize how much of a deal it is in practice. Atime updates are by far the biggest IO performance deficiency that Linux has today. Getting rid of atime updates would give us more everyday Linux performance than all the pagecache speedups of the past 10 years, _combined_.' And later severely beat atime about the head with a pointed stick: 'It's also perhaps the most stupid Unix design idea of all times. Unix is really nice and well done, but think about this a bit: 'For every file that is read from the disk, lets do a ... write to the disk! And, for every file that is already cached and which we read from the cache ... do a write to the disk!'" Well, I guess I can expect my Linux machine to become a little bit faster!"

Comments

atime vs ctime

[Intron]

Amazingly, standard Unix filesystems keep time of last access (atime), change of status (ctime), and file modification (mtime) but do not remember when the file was first created, which is something I have frequently wished for.

Re:Ummm..

[vidarh]

People are using Mutt because it works and has the features lots of people needs. I have to question why people keep upgrading just for the sake of it. As for an event system, Linux has had that too for ages - search for dnotify and inotify.

However Mutt's use of atime simply is cheap enough that there's simply never been a reason to change it all the time most people have had atime updates on anyway. If it ain't broke, don't fix it.