AB379B - PCI-X Dual Channel 4Gb/s Fibre Channel Adapter Performance Paper for Integrity Servers

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On the sx2000 Superdome Integrity servers the AB379B provides outstanding performance with linear scaling
up to 6 adapters, when all twelve ports are being used at 4Gb/s bandwidth. Additional adapters may be
added to provide greater connectivity.
Test results
The performance data presented in this paper was obtained using the diskbench I/O benchmarking utility.
Various block size tests were executed for read and write and bidirectional traffic on single and dual ports. The
IOPS metric is obtained with 1 KB block size transfers. The throughput metric is obtained with 256 KB block size
transfers. The throughput metric is useful in modeling large sequential transfers such as remote backup etc. The
IOPS metric is useful in modeling small transactional traffic.
I/Os Per Second (IOPS)
Chart 1a: IOPS Chart 1b: % CPU Utilization
Chart 1a shows the number of I/O operations per second for sequential read and writes operations on single
and dual ports of the AB379B measured on an 8-way rx6600. The X-axis is the number of ports and the Y-axis
the number of I/O operations per second.
Chart 1a shows excellent linear scaling of IOPS for single and dual ports. The number of read operations per
second for single port and dual ports is 103,800 and 199,000 while the number of write operations per
second for single port and dual ports is 102,000 and 198,400, respectively. The IOPS metric is limited by the
I/O processing overhead on the AB379B. The chart demonstrates excellent IOPS numbers for small size IOs on
both the ports of the AB379B.
Chart 1b shows the % CPU utilization in the rx6600 for the I/O operation tests. The X-axis is the number of the
Fibre Channel adapter ports. The Y-axis is the % CPU utilization. Nearly 20% of the 8 CPUs is used to achieve
over 100,000 I/Os per second through a single port, and 46% to 50% is used to achieve close to 200,000
I/Os per second through two ports. The CPU utilization per megabyte transferred in the single port tests is
lower than previous generations of Fibre Channel adapters, as discussed in the next section.
0
5
0000
10
0
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15
0
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20
0
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Read
103,800
199,000
Write
102,000
198,400
1
port
2
ports
IOPS
0
15
30
45
60
Read
19.7
50.4
Write
19.4
46.4
1 port
2
ports
% CPU Utilization