HP-UX IPSec vA.02.00 Performance and Sizing White Paper

16
Applying Performance Data
Use the following steps to create a sizing and performance report for a customer or test system:
1. Locate a server that is running HP-UX IPSec.
2. Assess the current environment, then forecast the potential future environment. Take the following
into account:
• Customer hardware
Processor speed
NIC bandwidth
• Network bandwidth
• Number of connections
3. Obtain current throughput and CPU utilization information for the system(s).
4. Use the current throughput with the performance data in this document to project throughput with
HP-UX IPSec. For example, on HP-UX Integrity servers, you can expect 3 – 5 % throughput
degradation with ESP-AES.
5. Use the current CPU utilization data with the data in this document to project additional CPU
requirements.
You can also use the following formula and the service demand data in this document to determine
the baseline CPU speed needed to obtain the customer’s desired throughput.
service_demand * CPI (cycles/instruction in test topology) *
desired_throughput = baseline CPU speed needed
The units for the items in the above formula are as follows:
service_demand: microseconds/KB
CPI: cycles/microsecond. For a 900 MHz processor, CPI is 900.
desired_throughput: KB/second
Using these units, the formula is:
(microseconds/KB) * (cycles/microsecond) * (KB/second) = baseline CPU
speed in cycles/second
Divide the resulting baseline CPU speed by 1,000,000 to get the processor speed in MHz; divide by
1,000,000,000 to get the processor speed in GHz.
If the desired throughput is represented in Mb/second (1,000,000 bits per second), multiply it by
122.07 to convert the throughput to KB/second (1024 bytes per second).
For example, service demand for sending 4096-byte TCP packets using ESP-AES on a one-way HP-UX
Integrity server with a 900 MHz processor is 30.56 microseconds/KB, as shown in Figure 3.
The customer’s desir
ed throughput is 160 Mb/second, or 19531.2 KB/second.
19531 * 30.56 * 900 = 537186124.8 (cycles/second)
537186124.8/1,000,000 = 537 (The minimum CPU speed needed just for HP-UX IPSec data
processing is 537 MHz.)