Date: Mon, 25 Oct 2004 09:37:25 -0400 From: "Don Bowman" <don@sandvine.com> To: <lukem.freebsd@cse.unsw.edu.au>, <freebsd-net@freebsd.org> Subject: RE: Underutilisation of CPU --- am I PCI bus bandwidth limited? Message-ID: <A8535F8D62F3644997E91F4F66E341FC9E36EA@exchange.sandvine.com>
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From: lukem.freebsd@cse.unsw.edu.au >=20 ... >=20 > This is rather confusing, as I cannot tell if the system is=20 > IO bound or CPU=20 > bound. Certainly I would not have expected the 133/64 PCI bus=20 > to be saturated=20 > given that peak throughput is around 550Mbit/s with 1024-byte=20 > packets. (Such a=20 > low figure is not unexpected given there are 2 syscalls per packet). You may find you have not loaned the em driver enough buffers, (max_rxd, max_txd). you may find you want to use device polling, poll on idle, and play with the polling parameters. In this config i have achieved ~2Gbps of throughput with these large packets, so i know it can be done.
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