On Tue, 2007-01-16 at 17:27 -0500, Trond Myklebust wrote: > On Tue, 2007-01-16 at 23:08 +0100, Peter Zijlstra wrote: > > Subject: nfs: fix congestion control > > > > The current NFS client congestion logic is severely broken, it marks the > > backing device congested during each nfs_writepages() call and implements > > its own waitqueue. > > > > Replace this by a more regular congestion implementation that puts a cap > > on the number of active writeback pages and uses the bdi congestion > > waitqueue. > > > > NFSv[34] commit pages are allowed to go unchecked as long as we are under > > the dirty page limit and not in direct reclaim.
> > What on earth is the point of adding congestion control to COMMIT? > Strongly NACKed. They are dirty pages, how are we getting rid of them when we reached the dirty limit? > Why 16MB of on-the-wire data? Why not 32, or 128, or ... Andrew always promotes a fixed number for congestion control, I pulled one from a dark place. I have no problem with a more dynamic solution. > Solaris already allows you to send 2MB of write data in a single RPC > request, and the RPC engine has for some time allowed you to tune the > number of simultaneous RPC requests you have on the wire: Chuck has > already shown that read/write performance is greatly improved by upping > that value to 64 or more in the case of RPC over TCP. Why are we then > suddenly telling people that they are limited to 8 simultaneous writes? min(max RPC size * max concurrent RPC reqs, dirty threshold) then? - 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/
