On Wed, 2005-03-30 at 09:50 -0500, Trond Myklebust wrote: > on den 30.03.2005 Klokka 09:26 (-0500) skreiv Lee Revell: > > On Tue, 2005-03-29 at 18:18 -0500, Trond Myklebust wrote: > > > ty den 29.03.2005 Klokka 18:04 (-0500) skreiv Lee Revell: > > > > I am seeing long latencies in the NFS client code. Attached is a ~1.9 > > > > ms latency trace. > > > > > > What kind of workload are you using to produce these numbers? > > > > > > > Here is the other long latency I am seeing in the NFS client. I posted > > this before, but did not cc: the correct people. > > > > It looks like nfs_wait_on_requests is doing thousands of > > radix_tree_gang_lookups while holding some lock. > > That's normal and cannot be avoided: when writing, we have to look for > the existence of old nfs_page requests. The reason is that if one does > exist, we must either coalesce our new dirty area into it or if we > can't, we must flush the old request out to the server.
But holding a spinlock for 3ms is not acceptable. _Something_ has to be done. Can't the lock be dropped and reacquired after processing N requests where N is some reasonable number? Lee - 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/
