Folks -
I was trying to look at bonding vs discrete links and so put a couple dual-port
e1000-driven NICs:
4a:01.1 Ethernet controller: Intel Corporation 82546GB Gigabit Ethernet
Controller (rev 03)
Subsystem: Hewlett-Packard Company HP Dual Port 1000Base-T [A9900A]
into a pair of 8 core systems running a 2.6.22.2 kernel. This gave me:
hpcpc109:~/netperf2_trunk# ethtool -i eth2
driver: e1000
version: 7.3.20-k2-NAPI
firmware-version: N/A
bus-info: 0000:49:02.0
for the e1000 driver. I connected the two systems back-to-back and started
running some tests. In the course of trying to look at something else
(verifying the results reported by bwm-ng) I enabled demo-mode in netperf
(./configure --enable-demo) and noticed a considerable oscillation. I undid the
bond and repeated the experiment with a discrete NIC:
hpcpc109:~/netperf2_trunk# src/netperf -t TCP_RR -H 192.168.2.105 -D 1.0 -l 15
TCP REQUEST/RESPONSE TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.2.105
(192.168.2.105) port 0 AF_INET : demo : first burst 0
Interim result: 10014.93 Trans/s over 1.00 seconds
Interim result: 10015.79 Trans/s over 1.00 seconds
Interim result: 10014.30 Trans/s over 1.00 seconds
Interim result: 10016.29 Trans/s over 1.00 seconds
Interim result: 10085.80 Trans/s over 1.00 seconds
Interim result: 17526.61 Trans/s over 1.00 seconds
Interim result: 20007.60 Trans/s over 1.00 seconds
Interim result: 19626.46 Trans/s over 1.02 seconds
Interim result: 10616.44 Trans/s over 1.85 seconds
Interim result: 10014.88 Trans/s over 1.06 seconds
Interim result: 10015.79 Trans/s over 1.00 seconds
Interim result: 10014.80 Trans/s over 1.00 seconds
Interim result: 10035.30 Trans/s over 1.00 seconds
Interim result: 13974.69 Trans/s over 1.00 seconds
Local /Remote
Socket Size Request Resp. Elapsed Trans.
Send Recv Size Size Time Rate
bytes Bytes bytes bytes secs. per sec
16384 87380 1 1 15.00 12225.77
16384 87380
On a slightly informed whim I tried disabling the interrupt thottle on both
sides (modprobe e1000 InterruptThrottleRate=0,0,0,0,0,0,0,0) and re-ran:
hpcpc109:~/netperf2_trunk# src/netperf -t TCP_RR -H 192.168.2.105 -D 1.0 -l
15TCP REQUEST/RESPONSE TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to
192.168.2.105 (192.168.2.105) port 0 AF_INET : demo : first burst 0
Interim result: 18673.68 Trans/s over 1.00 seconds
Interim result: 18685.01 Trans/s over 1.00 seconds
Interim result: 18682.30 Trans/s over 1.00 seconds
Interim result: 18681.05 Trans/s over 1.00 seconds
Interim result: 18680.25 Trans/s over 1.00 seconds
Interim result: 18742.44 Trans/s over 1.00 seconds
Interim result: 18739.45 Trans/s over 1.00 seconds
Interim result: 18723.52 Trans/s over 1.00 seconds
Interim result: 18736.53 Trans/s over 1.00 seconds
Interim result: 18737.61 Trans/s over 1.00 seconds
Interim result: 18744.76 Trans/s over 1.00 seconds
Interim result: 18728.54 Trans/s over 1.00 seconds
Interim result: 18738.91 Trans/s over 1.00 seconds
Interim result: 18735.53 Trans/s over 1.00 seconds
Interim result: 18741.03 Trans/s over 1.00 seconds
Local /Remote
Socket Size Request Resp. Elapsed Trans.
Send Recv Size Size Time Rate
bytes Bytes bytes bytes secs. per sec
16384 87380 1 1 15.00 18717.94
16384 87380
and then just for grins I tried just disabling it on one side, leaving the other
at defaults:
hpcpc109:~/netperf2_trunk# src/netperf -t TCP_RR -H 192.168.2.105 -D 1.0 -l
15TCP REQUEST/RESPONSE TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to
192.168.2.105 (192.168.2.105) port 0 AF_INET : demo : first burst 0
Interim result: 19980.84 Trans/s over 1.00 seconds
Interim result: 19997.60 Trans/s over 1.00 seconds
Interim result: 19995.60 Trans/s over 1.00 seconds
Interim result: 20002.60 Trans/s over 1.00 seconds
Interim result: 20011.58 Trans/s over 1.00 seconds
Interim result: 19985.66 Trans/s over 1.00 seconds
Interim result: 20002.60 Trans/s over 1.00 seconds
Interim result: 20010.58 Trans/s over 1.00 seconds
Interim result: 20012.60 Trans/s over 1.00 seconds
Interim result: 19993.63 Trans/s over 1.00 seconds
Interim result: 19979.63 Trans/s over 1.00 seconds
Interim result: 19991.58 Trans/s over 1.00 seconds
Interim result: 20011.60 Trans/s over 1.00 seconds
Interim result: 19948.84 Trans/s over 1.00 seconds
Local /Remote
Socket Size Request Resp. Elapsed Trans.
Send Recv Size Size Time Rate
bytes Bytes bytes bytes secs. per sec
16384 87380 1 1 15.00 19990.14
16384 87380
It looks like the e1000 interrupt throttle autotuning works very nicely when the
other side isn't doing any, but if the other side is also trying to autotune it
doesn't seem to stablize. At least not during a netperf TCP_RR test.
Does anyone else see this? To try to eliminate netperf demo mode I re-ran
without it and got the same end results.
rick jones
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