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realtime:documentation:howto:tools:cyclictest:test-design [2018/08/23 15:03] ebugden [System Load] Add hackbench link |
realtime:documentation:howto:tools:cyclictest:test-design [2021/12/02 17:48] (current) bartwensley [Option Selection] |
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* [[realtime:documentation:howto:tools:cyclictest:options:duration|Test duration]] | * [[realtime:documentation:howto:tools:cyclictest:options:duration|Test duration]] | ||
* [[realtime:documentation:howto:tools:cyclictest:options:mlockall|Prevent Cyclictest pages from being paged out of memory]] (--mlockall) | * [[realtime:documentation:howto:tools:cyclictest:options:mlockall|Prevent Cyclictest pages from being paged out of memory]] (--mlockall) | ||
- | * [[realtime:documentation:howto:tools:cyclictest:options:nanosleep|Use clock_nanosleep( )]] (--nanosleep) | ||
- | When running Cyclictest on a symmetic multi-processing (SMP) system, specifying the --smp option can be useful as it takes care of some of the options mentioned above without having to specify them all individually. | + | When running Cyclictest on a symmetric multi-processing (SMP) system, specifying the --smp option can be useful as it takes care of some of the options mentioned above without having to specify them all individually. |
===== Observer Effect ===== | ===== Observer Effect ===== | ||
When designing a test, it is important to minimize the effect that running Cyclictest could have on the latencies that are being observed in a system. For example, when measuring the latencies on a specific CPU, make sure that the main Cyclictest thread is not running on that CPU, otherwise the additional context switches will influence the latencies that are measured. A technique for doing this is presented on the [[realtime:documentation:howto:tools:cyclictest:faq#how-can-the-influence-of-cyclictest-be-minimized-when-evaluating-latencies-on-an-isolated-set-of-cpus|Cyclictest FAQ]]. | When designing a test, it is important to minimize the effect that running Cyclictest could have on the latencies that are being observed in a system. For example, when measuring the latencies on a specific CPU, make sure that the main Cyclictest thread is not running on that CPU, otherwise the additional context switches will influence the latencies that are measured. A technique for doing this is presented on the [[realtime:documentation:howto:tools:cyclictest:faq#how-can-the-influence-of-cyclictest-be-minimized-when-evaluating-latencies-on-an-isolated-set-of-cpus|Cyclictest FAQ]]. |