What is the CPU Number for Affinity option, "sqlio -p"?

The CPU Number for Affinity option, "sqlio -p", specifies a specific CPU to run SQLIO.

The default value is "", all CPUs. In this case, all CPUs are used.

Example 1 - Run SQLIO with the first CPU:

C:\fyicenter\SQLIO>sqlio -p0

1 thread reading for 30 secs from file testfile.dat
        using 2KB IOs over 128KB stripes with 64 IOs per run
        affinity on cpu number 0
initialization done
CUMULATIVE DATA:
throughput metrics:
IOs/sec:  2337.71
MBs/sec:     4.56

Example 2 - Run SQLIO with the 4th CPU:

C:\fyicenter\SQLIO>sqlio -p3

1 thread reading for 30 secs from file testfile.dat
        using 2KB IOs over 128KB stripes with 64 IOs per run
        affinity on cpu number 3
initialization done
CUMULATIVE DATA:
throughput metrics:
IOs/sec:  1957.83
MBs/sec:     3.82

Example 3 - Run SQLIO with all CPUs:

C:\fyicenter\SQLIO>sqlio

1 thread reading for 30 secs from file testfile.dat
        using 2KB IOs over 128KB stripes with 64 IOs per run
initialization done
CUMULATIVE DATA:
throughput metrics:
IOs/sec:  3852.54
MBs/sec:     7.52

As you can see, when using all CPUs, the throughput is better as we expected.

⇒ "sqlio -a" - CPU Mask for Affinity

⇐ "sqlio -o" - Outstanding Tests in Asynchronous Queue

⇑ Getting Started with Microsoft SQLIO

⇑⇑ SQLIO Disk I/O Benchmark Test Tutorials