Re: Poor gige performance with 2.4.20-pre*

Richard Gooch wrote:

Ben Greear writes:

quoted

Richard Gooch wrote:

quoted

 Hi, all. For a while now I've noticed poor performance with gige
cards under 2.4.19 and 2.4.20-pre*. At first I thought it was because
of the cheap-ass Addtron cards I bought (these use the ns83820 chip).
But now that the Intel E1000 cards are pretty cheap too, I've grabbed
a couple (part number: PWLA8390MT) and see the same problem. In fact,
the E1000 cards are no better than the Addtron cards. I'm using the
D-Link DGS-1008T 8-port gige switch. MTU=1500 bytes.

Try setting the TxDescriptors=4096 RxDescriptors=1024 when loading the
e1000 module, that helps tremendously when using smaller packets.

Didn't help at all. Just to summarise, I've got:
options e1000 TxDescriptors=4096 RxDescriptors=1024
net.ipv4.tcp_rmem = 262144 262144 262144
net.ipv4.tcp_wmem = 262144 262144 262144
MTU=1500

I'm doing read(2)/write(2) to/from a user-space buffer over a TCP
socket with 256 KiB buffer size.

Is the E1000 supposed to have hardware interrupt mitigation (thus
avoiding the need for NAPI)?

NAPI did not greatly improve the performance I saw with larger packets,
but it did help with smaller (say, 60 byte) packets.

One other thing I saw with TCP connections:  They started off slow, but after
a few seconds they were reacing their peak throughput.  How long are you running
your test?

Ben

				Regards,

					Richard....
Permanent: rgooch@atnf.csiro.au
Current:   rgooch@ras.ucalgary.ca

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Ben Greear [off-list ref]       <Ben_Greear AT excite.com>
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