Hello,
I've performed some benchmarks using 2.4.19/20 kernels and the tigon3
driver. I've found that 2.4.19 performs better than 2.4.20.
This is the hardware that I've used :
** host 103 and host 104 :
Dual Pentium 3 1 GHz - 512 RAM
Network Card : 3c996-T
(identified in /proc/pci by :
Ethernet controller: BROADCOM Corporation NetXtreme BCM5700 Gigabit
Ethernet (rev 18).)
redhat 7.2
** host 110 :
Sinlge Pentium 4 2.40 GHz - 256 RAM
Network Card : 3c996-T
redhat 7.2
** network switch :
3com 17700 - GE network
I've used two benchmarks :
** lmbench-3.0-a2 :
on the server :
# ./bw_tcp -s
on the client :
# ./bw_tcp target_ip
** iperf version 1.6.4 (3 Dec 2002) pthreads
on the server :
# ./iperf -s
on the client :
# ./iperf -c target_ip -t 60
I've used the following monitor :
** sar from sysstat-4.0.1-2
on every node :
sar -I irq_network_card -n DEV -u 3 0
Here are the results (running every benchmark 10 times and taking the
average results) :
** bw_tcp :
server 103 - 2.4.19smp
clients 104-2.4.19smp 104-2.4.20smp 110-2.4.19up 110-2.4.20up
bw 101.9 63.7 89.2 76.3
(MB/s)
intr/s (reported by sar)
client 6743 40165 6772 39680
server 5628 4018 6705 6674
** iperf :
client 104 - 2.4.19smp
servers 103-2.4.19smp 103-2.4.20smp 110-2.4.19up 110-2.4.20up
iperf 116.6 96.5 107.2 79.9
(MB/s)
intr/s (reported by sar)
client 6775 6799 6727 6774
server 6800 49029 6772 39515
As you can see there is a loss in performance between 2.4.19 and 2.4.20
and a big rise in the number of interrupts generated by the network card.
So here are my questions :
1) Is NAPI enabled in 2.4.20 ? If not, how could I enable it ? The idea
behind these tests is to evaluate NAPI.
2) Why is there such a high rate of interrupts generated by the network
card ?
Thank you
Mathias Gug
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