Load average

Ideally, a performant job flow should be consuming as much CPU as is available. The load average on the machine should be two to three times the value as the number of processors on the machine (for example, an 8-way SMP should have a load average of roughly 16-24). Some operating systems, such as HPUX, show per-processor load average. In this case, load average should be 2-3, regardless of number of CPUs on the machine.

If the machine is not CPU-saturated, it indicates a bottleneck might exist elsewhere in the flow. A useful strategy in this case is to over-partition your data, as more partitions cause extra processes to be started, utilizing more of the available CPU power.

If the flow cause the machine to be fully loaded (all CPUs at 100%), then the flow is likely to be CPU limited, and some determination needs to be made as to where the CPU time is being spent (setting the APT_PM_PLAYER _TIMING environment variable can be helpful here - see the following section).

The commands top or uptime can provide the load average.