The vcpuperf utility measures your server's CPU processing speed and compares it against benchmarks for common server CPUs. The utility performs a CPU test and measures the time it takes to complete the test. The lower the number scored on the test, the better the performance of the CPU.
The vcpuperf utility also checks the high and low load times to determine if CPU throttling is enabled. If a server's low-load computation time is significantly longer than the high-load computation time, CPU throttling may be enabled. CPU throttling is a power-saving feature. However, CPU throttling can reduce the performance of your server. Vertica recommends disabling CPU throttling to enhance server performance.
|Run in quiet mode. Quiet mode displays only the CPU Time, Real Time, and high and low load times.|
- CPU Time: the amount of time it took the CPU to run the test.
- Real Time: the total time for the test to execute.
- High load time: The amount of time to run the load test while simulating a high CPU load.
- Low load time: The amount of time to run the load test while simulating a low CPU load.
The following example shows a CPU that is running slightly slower than the expected time on a Xeon 5670 CPU that has CPU throttling enabled.
[root@node1 bin]# /opt/vertica/bin/vcpuperf Compiled with: 4.1.2 20080704 (Red Hat 4.1.2-52) Expected time on Core 2, 2.53GHz: ~9.5s Expected time on Nehalem, 2.67GHz: ~9.0s Expected time on Xeon 5670, 2.93GHz: ~8.0s This machine's time: CPU Time: 8.540000s Real Time:8.710000s Some machines automatically throttle the CPU to save power. This test can be done in <100 microseconds (60-70 on Xeon 5670, 2.93GHz). Low load times much larger than 100-200us or much larger than the corresponding high load time indicate low-load throttling, which can adversely affect small query / concurrent performance. This machine's high load time: 67 microseconds. This machine's low load time: 208 microseconds.