Glossary of Terms
Bimodal Performance Behavior
- Each NULLSTONE performance test has been designed to exhibit
Bimodal Performance Behavior. That is, the optimization being tested
dominates the code in the test, and failure to perform the optimization
being tested will significantly affect the run-time performance of the
- Measured in seconds, the time to compile a test. Lower is better.
- Measured in iterations per second, the rate at which the test can
be executed after the optimization under test has been successfully optimized.
The Ideal Rate for a test is dependent upon system features such as
architecture, micro-architecture, cache, and memory size.
- Measured in iterations per second, the rate at which the test code
fragment can be executed. Higher is better.
- A percentage between 0% and 100% inclusive, the ratio of the NULLSTONE Rate
and the Ideal Rate. A NULLSTONE Ratio of 100% is a perfect score, and
indicates that the compiler performed the optimization being tested.
Compilation failures and execution failures are reported as 0%. Higher is
- A decrease in the NULLSTONE Rate for a performance test when compared to
a previous release of the same compiler.
- The number of tests in a particular category.
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