Here are results of a simple run (average of three results, bigger is better) of tools from unixbench suite with WITNESS+INVARIANTS enabled and disabled:

| . | **aritoh** | **float** | **context1** | **syscall** |
| WITNESS+INVARIANTS | 76467098 | 7477383 |  66894 |  460400 |
| Plain | 78024481 | 7549189 |  265514 |  1308646 |

This benchmark was performed on i386 Athlon64 1.6 GHz machine, on %%FreeBSD%% 6.1-RELEASE. There's no statistical analysis, but there's clearly an order-of-magnitude impact on some workloads.

WITNESS and INVARIANTS are debug options that should not be enabled on production systems.

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{{tag>Performance}}
{{tag>Stale}}