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Intelligent NIC Installation and Tuning Guide
NetXen, Inc.
Appendix A. Tuning Guidelines
Appendix A Tuning Guidelines
A.1
Windows Performance Tools
A.1.1
NTttcp (Windows)
There are two switches on
ntttcp
that boost performance:
-a
and
-rb
.
Running
ntttcp
without an optimal value for the
-a
switch and without the
-rb
switch is
acceptable for the Gigabit NIC product.
In the 10G NIC product, however, and in particular with fewer threads on Windows,
performance is limited by the Receive window for the most part and by the outstanding
I/O (
-a
) value, regardless of hardware limitations.
For receive, an optimal value is
16
for
-a
and
512000
for
-rb
(or something similar). With
these values, a single thread should perform closer to a multi-thread configuration.
ntttcpr -m 16,0,
<rcv ipaddr>
-n <# of tcp segs for snd/rcv> -a 16
For transmit,
-a
should be a value less than 8. The more threads, the lower the number
should be.
Note:
The send and receive side NTTTCP commands must use the receive side’s IP address.
Steps for NIC Performance Testing using NTTTCP on Windows
1
Install Windows Server 2003 Service Pack 2.
2
Enable Windows Scaling
Set TCp1323Opts parameter value to 1, if the parameter does not exist, create it:
"regedit" to HKLM\system\currentcontrolset\services\Tcpip\Parameters
3
Set Tcp window size. From regedit, create a parameter “TcpWindowSize” and set to a
decimal value of 512000.
4
The drivers property sheet default is 1500. For Jumbo, set the frame size to 8000.
Table 20 ntttcpr Command Options
Command Options
ntttcpr
Description
-l
Message size in bytes. Default is 64K.
-m
Number of threads.
0
CPU number.
IP
Address
Receive IP address.
(Send side also uses receive side's IP Address).
-n
Number of TCP segments.
-a
Number of requests in parallel.
(Send and receive side values must match).
-rb
Receive window size on the receiver.
