Tangential aside:
On Tue, 02 Oct 2007, Rick Jones wrote:
> *) depending on the quantity of CPU around, and the type of test one is
> running,
> results can be better/worse depending on the CPU to which you bind the
> application. Latency tends to be best when running on the same core as takes
> interrupts from the NIC, bulk transfer can be better when running on a
> different
> core, although generally better when a different core on the same chip. These
> days the throughput stuff is more easily seen on 10G, but the netperf service
> demand changes are still visible on 1G.
Interesting. I was going to say that I've generally had the opposite
experience when it comes to bulk data transfers, which is what I would
expect due to CPU caching effects, but that perhaps it's motherboard/NIC/
driver dependent. But in testing I just did I discovered it's even
MTU dependent (most of my normal testing is always with 9000-byte
jumbo frames).
With Myricom 10-GigE NICs, NIC interrupts on CPU 0 and nuttcp app
running on CPU 1 (both transmit and receive sides), and using 9000-byte
jumbo frames:
[EMAIL PROTECTED] ~]# nuttcp -w10m 192.168.88.16
10078.5000 MB / 10.02 sec = 8437.5396 Mbps 100 %TX 99 %RX
With Myricom 10-GigE NICs, and both NIC interrupts and nuttcp app
on CPU 0 (both transmit and receive sides), again using 9000-byte
jumbo frames:
[EMAIL PROTECTED] ~]# nuttcp -w10m 192.168.88.16
11817.8750 MB / 10.00 sec = 9909.7537 Mbps 100 %TX 74 %RX
Same tests repeated with standard 1500-byte Ethernet MTU:
With Myricom 10-GigE NICs, NIC interrupts on CPU 0 and nuttcp app
running on CPU 1 (both transmit and receive sides), and using
standard 1500-byte Ethernet MTU:
[EMAIL PROTECTED] ~]# nuttcp -M1460 -w10m 192.168.88.16
5685.9375 MB / 10.00 sec = 4768.0951 Mbps 99 %TX 98 %RX
With Myricom 10-GigE NICs, and both NIC interrupts and nuttcp app
on CPU 0 (both transmit and receive sides), again using standard
1500-byte Ethernet MTU:
[EMAIL PROTECTED] ~]# nuttcp -M1460 -w10m 192.168.88.16
4974.0625 MB / 10.03 sec = 4161.6015 Mbps 100 %TX 100 %RX
Now back to your regularly scheduled programming. :-)
-Bill
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