On Jun 29, 2009, at 1:44 PM, Scott Atchley wrote:
Right, and that's what I did before, with sensible results I thought.
Repeating it now on Centos 5.2 and OpenSuSE 10.3, it doesn't behave
sensibly, and I don't know what's different from the previous SuSE
results apart, probably, from the minor kernel version. If I set
rx-frames=0, I see this:
rx-usec latency (µs)
20 34.6
12 26.3
6 20.0
1 14.8
whereas if I just set rx-frames=1, I get 14.7 µs, roughly
independently
of rx-usec. (Those figures are probably ±∼0.2µs.)
That is odd. I have only tested with Intel e1000 and our myri10ge
Ethernet driver. The Intel driver does not let you specify value
other than certain settings (0, 25, etc.). The myri10ge driver does
allow you to specify any value.
Your results may be specific to that driver.
As Patrick kindly pointed out, you are using rx-frames and not rx-
usec. They are not equivalent.
Scott
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