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realtime:documentation:howto:debugging:cyclictest:test-design:start [2018/08/06 13:23] ebugden [System Load] Add link to worst case latency test setup examples |
realtime:documentation:howto:debugging:cyclictest:test-design:start [2018/08/21 10:48] ebugden Move from temporary location to main tools page |
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This page presents some of the concepts to keep in mind when setting up a system for measuring latencies and when selecting Cyclictest options. The purpose of this information is to facilitate measuring latencies correctly. However, measuring latencies and evaluating a system's performance remains a difficult task that requires an in-depth knowledge of the platform, its intended final purpose (application), and its latency requirements. | This page presents some of the concepts to keep in mind when setting up a system for measuring latencies and when selecting Cyclictest options. The purpose of this information is to facilitate measuring latencies correctly. However, measuring latencies and evaluating a system's performance remains a difficult task that requires an in-depth knowledge of the platform, its intended final purpose (application), and its latency requirements. | ||
- | When learning how to design a test, it is useful to have a look at [[realtime:documentation:howto:debugging:cyclictest:result-examples|examples of results]] that show the effect of different loads and parameters on the latencies measured by Cyclictest. It is also important to understand [[realtime:documentation:howto:debugging:cyclictest:start#technical-explanation|how Cyclictest works]] before reading the rest of the content on this page. | + | When learning how to design a test, it is useful to have a look at [[realtime:documentation:howto:tools:cyclictest:result-examples|examples of results]] that show the effect of different loads and parameters on the latencies measured by Cyclictest. It is also important to understand [[realtime:documentation:howto:tools:cyclictest:start#technical-explanation|how Cyclictest works]] before reading the rest of the content on this page. |
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===== 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:debugging: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]]. |