Re: [ANNOUNCE] iSCSI enterprise target software

[Ming Zhang <mingz@ele.uri.edu>]

On Tue, 2005-03-01 at 16:04, Bryan Henderson wrote:
> >it is hard to beat linux kernel [page] cache performance though.
> 
> It's quite easy to beat it for particular applications.  You can use 
> special knowledge about the workload to drop pages that won't be accessed 
> soon in favor of pages that will, not clean a page that's just going to 
> get discarded or overwritten soon, allocate less space to less important 
> data, and on and on.
u are talking about application aware caching/prefetching stuff. but i
prefer to modifying kernel page cache a little bit while make use of
most of the code there.


> 
> And that's pretty much the whole argument for direct I/O.  Sometimes the 
> code above the filesystem layer is better at caching.
> 
> Of course, in this thread we're not talking about beating the page cache 
> -- we're just talking about matching it, while reaping other benefits of 
> user space code vs kernel code.
> 
yes, we went too far.

> --
> Bryan Henderson                          IBM Almaden Research Center
> San Jose CA                              Filesystems