On Mon, Mar 22, 2004 at 10:00:18AM -0500, Thor Lancelot Simon wrote:
> 
> Having looked at (and instrumented) the I/O spreading rotor as it is in
> your patch, I am not so sure it really does anything unless you happen
> to have disks that can clear well upwards of 8,192 metadata operations
> in a single second.  I implemented a very simple form of automatic
> tuning for the spreading, and it _seems_ to work as intended.  I'm
> attaching a patch.
> 
> However, there are some significant caveats:
> 
> 1) I am not _certain_ that all directory I/O appears in the syncer
>    worklists as the vnode, of type VDIR, for each directory.  I have
>    read and reread the code but I would like more people to look at
>    this.

Hm.  I'm particularly unsure about this -- because when I run a benchmark
that does two threads of heavy directory I/O, I see "dirburst" drop
quickly to the minimum, even when I intervene with DDB and set it to the
maximum.  Are all these directory writes, too, going on the mount point's
vnode?  Or am I counting/tuning wrong in some other way?

Thor