On Sat, 4 Aug 2007 18:37:33 +0200 Ingo Molnar [off-list ref] wrote:

* Linus Torvalds [off-list ref] wrote:

quoted

quoted

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.

yeah, it's really ugly. But otherwise i've got no real complaint about 
ext3 - with the obligatory qualification that "noatime,nodiratime" in 
/etc/fstab is a must. This speeds up things very visibly - especially 
when lots of files are accessed. It's kind of weird that every Linux 
desktop and server is hurt by a noticeable IO performance slowdown due 
to the constant atime updates,

Not just more IO: it will cause great gobs of blockdev pagecache to remain
in memory, too.

while there's just two real users of it: 
tmpwatch [which can be configured to use ctime so it's not a big issue] 
and some backup tools. (Ok, and mail-notify too i guess.) Out of tens of 
thousands of applications. So for most file workloads we give Windows a 
20%-30% performance edge, for almost nothing. (for RAM-starved kernel 
builds the performance difference between atime and noatime+nodiratime 
setups is more on the order of 40%)

	Ingo

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