serious networking (em) performance (ggate and NFS) problem

Sean McNeil sean at
Sun Nov 21 09:27:31 PST 2004

On Sun, 2004-11-21 at 21:27 +0900, Shunsuke SHINOMIYA wrote:
>  Jeremie, thank you for your comment.
>  I did simple benchmark at some settings.
>  I used two boxes which are single Xeon 2.4GHz with on-boarded em.
>  I measured a TCP throughput by iperf.
>  These results show that the throughput of TCP increased if Interrupt
> Moderation is turned OFF. At least, adjusting these parameters affected
> TCP performance. Other appropriate combination of parameter may exist.

I have found interrupt moderation to seriously kill gigE performance.
Another test you can make is to have the driver always defrag packets in
em_encap().  Something like

		m_head = m_defrag(*m_headp, M_DONTWAIT);
		if (m_head == NULL)
			return ENOBUFS;

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