Re: [PATCH 00/23] per device dirty throttling -v8

Linus Torvalds
2007-08-04T16:18:58Z

On Sat, 4 Aug 2007, Ingo Molnar wrote:

> > [ my personal interest in this is the following regression: every time
> > i start a large kernel build with DEBUG_INFO on a quad-core 4GB RAM
> > box, i get up to 30 seconds complete pauses in Vim (and most other
> > tasks), during plain editing of the source code. (which happens when
> > Vim tries to write() to its swap/undo-file.) ]
>
> hm, it turns out that it's due to vim doing an occasional fsync not only
> on writeout, but during normal use too. "set nofsync" in the .vimrc
> solves this problem.

Yes, that's independent. The fact is, ext3 *sucks* at fsync. I hate hate
hate it. It's totally unusable, imnsho.

The whole point of fsync() is that it should sync only that one file, and
avoid syncing all the other stuff that is going on, and ext3 violates
that, because it ends up having to sync the whole log, or something like
that. So even if vim really wants to sync a small file, you end up waiting
for megabytes of data being written out.

I detest logging filesystems.

Linus