Date: Tue, 11 Feb 2014 13:58:54 -0500 From: John Baldwin <jhb@freebsd.org> To: freebsd-net@freebsd.org Cc: rmacklem@freebsd.org, Garrett Wollman <wollman@freebsd.org> Subject: Re: ixgbe/NFS m_defrag() instrumentation Message-ID: <201402111358.54764.jhb@freebsd.org> In-Reply-To: <21233.52147.912022.488615@hergotha.csail.mit.edu> References: <21233.52147.912022.488615@hergotha.csail.mit.edu>
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On Wednesday, February 05, 2014 12:27:15 am Garrett Wollman wrote: > I instrumented calls to m_defrag() in ixgbe. As expected, it gets > called *a lot* when NFS is running with the default read size of 64k. > A simple benchmark (single-threaded sequential read of a 128 GB file > which I didn't even run to completion) tells the tale: > > $ sysctl dev.ix.0.mbuf_defrag_attempted > dev.ix.0.mbuf_defrag_attempted: 1737994 > > (There's already a similar counter for m_defrag() failures, which made > it easy to add this counter. Unfortunately, there is no analogous > instrumentation in cxgbe so I couldn't do likewise for that NIC.) Is this due to the other thread Rick has about TSO interacting with NFS? Do these go away if you disable TSO on the interface? -- John Baldwin
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