On Thu, Dec 27, 2007 at 05:00:12PM +0200, saeed bishara wrote: > > >> Are you using TCP? Are you using NFSv4, or an older version? > > > I'm using NFSv3/UDP. > > > > IMO, you definitely want TCP and NFSv4. Much better network behavior, > > with some of the silly UDP limits (plus greatly improved caching > > behavior, due to v4 delegations). > the clients of my system going to be embedded system with low > performance cpus and I need UDP as it needs less cpu power.
You can try the attached adaptive readahead patch. Apply it on your server and compile kernel with CONFIG_ADAPTIVE_READAHEAD. Use large 1MB readahead on server and small readahead on clients. > > > when I run local dd with bs=4K, I can see that the average IO size is > > > more than 300KB. > > > > Read-ahead is easier in NFSv4, because the client probably has the file > > delegated locally, and has far less need to constantly revalidate file > > mapping(s). > I'll check that. > but what about the server side? why the issued IO's are only as twice > as the size of the NFS requests? The readahead code is helpless in NFSv3 :-( Use NFS over TCP and rsize=readahead=1MB on client side could help. But if you prefer UDP, the above patch may help you :-) Fengguang -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/