RE: Underutilisation of CPU --- am I PCI bus bandwidth limited?
From: Don Bowman (don_at_sandvine.com)
Date: 10/25/04
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- Maybe in reply to: lukem.freebsd_at_cse.unsw.edu.au: "Underutilisation of CPU --- am I PCI bus bandwidth limited?"
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Date: Mon, 25 Oct 2004 09:37:25 -0400 To: <lukem.freebsd@cse.unsw.edu.au>, <freebsd-net@freebsd.org>
From: lukem.freebsd@cse.unsw.edu.au
>
...
>
> This is rather confusing, as I cannot tell if the system is
> IO bound or CPU
> bound. Certainly I would not have expected the 133/64 PCI bus
> to be saturated
> given that peak throughput is around 550Mbit/s with 1024-byte
> packets. (Such a
> 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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- Previous message: gnn_at_freebsd.org: "Updated scope6.c locking patch..."
- Maybe in reply to: lukem.freebsd_at_cse.unsw.edu.au: "Underutilisation of CPU --- am I PCI bus bandwidth limited?"
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