Performance Report for A5483A, A5513A, and A5515A ATM/155 and ATM/622 Adapters
Performance Report on ATM adapters, Part No. A5483A, A5513A, and A5515A 09/30/99 6
Table 8: TCP Throughput Results on LAN Emulation Interface (N4000:8 CPUs, 4 155 Adapters)
Test/Interface
LANE
MTU 9218
bytes
LANE
MTU 1516
bytes
Outbound TCP Throughput Mbps 538 475
CPU utilization % 2.75 6.3
Inbound TCP Throughput Mbps 529 268
CPU Utilization % 4.04 3.28
Bidirectional TCP Throughput Mbps 772 338
CPU Utilization % 6.8 4.90
Table 9: TCP Throughput Results on LAN Emulation Interface (N4000: 8 CPUs, 4 622 Adapters)
Test/Interface
LANE
MTU 9218
bytes
LANE
MTU 1516
bytes
Outbound TCP Throughput Mbps 1567 598
CPU utilization % 14.36 11.83
Inbound TCP Throughput Mbps 1221 444
CPU Utilization % 11.91 6.91
Bidirectional TCP Throughput Mbps 1529 680
CPU Utilization % 23.54 20.88
Tuning Guidelines
• System-related Guidelines
When installing multiple adapters, make sure the adapters are evenly distributed in the card
cages on V series platforms. In particular, avoid installing more than 3 155 adapters and more
than 1 622 adapter per PCI Controller on the V series platforms. On N-class servers, install the
622 adapters in the Twin Turbo slots. Also, evenly distribute the adapters in slots of both I/O
controllers on N-class systems.
For best performance, we recommend that all four memory carriers be installed on the N-class
systems. Also, distribute the memory modules evenly on the memory carriers. When using
multiple adapters, 4 Gbytes of memory is recommended. For single adapter installations, the
memory size of 1 Gbytes is recommended.
• Application-related Guidelines
For standard applications (for example, ftp, NFS, and others), if the socket size is configurable,
choose socket size (on the receiving end) and message length values of at least 144 Kbytes. This
sets the TCP window size parameter. Alternatively, the TCP window size on the receiving end
can be set using the ndd command. Set the tcp_recv_hiwater_def parameter to 144 Kbytes. If the
receiving system is a non-HP platform, use a command equivalent to the ndd command on that
platform.
For a customized application, use SETSOCKOPT IOCTL to define a socket size of at least 128
Kbytes. When possible, design the application to use the largest message size possible.