[lkml]   [2005]   [Apr]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectUncached stat performace [ Was: Re: Kernel SCM saga.. ]
On Fri, Apr 08, 2005 at 12:39:26PM -0700, Linus Torvalds wrote:
> One of the reasons I do inode numbers in the "index" file (apart from
> checking that the inode hasn't changed) is in fact that "stat()" is damn
> slow if it causes seeks. Since your stat loop is entirely
> You can optimize your stat() patterns on traditional unix-like filesystems
> by just sorting the stats by inode number (since the inode number is
> historically a special index into the inode table - even when filesystems
> distribute the inodes over several tables, sorting will generally do the
> right thing from a seek perspective). It's a disgusting hack, but it
> literally gets you orders-of-magnitude performance improvments in many
> real-life cases.

It does, so why isn't there a way to do this without the disgusting
hack? (Your words, not mine :) )

E.g, wouldn't a aio_stat() allow simular or better speedups in a way
that doesn't depend on ext2/3 internals?

I bet it would make a significant difference from things like "ls -l" in
large uncached directories and imap-servers with maildir?

Ragnar Kjørstad
Software Engineer
Scali -
Scaling the Linux Datacenter
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

 \ /
  Last update: 2005-04-08 22:15    [W:0.169 / U:1.760 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site