On 21/07/2020 14:42, Pratik Rajesh Sampat wrote: > v2: https://lkml.org/lkml/2020/7/17/369 > Changelog v2-->v3 > Based on comments from Gautham R. Shenoy adding the following in the > selftest, > 1. Grepping modules to determine if already loaded > 2. Wrapper to enable/disable states > 3. Preventing any operation/test on offlined CPUs > --- > > The patch series introduces a mechanism to measure wakeup latency for > IPI and timer based interrupts > The motivation behind this series is to find significant deviations > behind advertised latency and resisdency values Why do you want to measure for the timer and the IPI ? Whatever the source of the wakeup, the exit latency remains the same, no ? Is all this kernel-ish code really needed ? What about using a highres periodic timer and make it expires every eg. 50ms x 2400, so it is 120 secondes and measure the deviation. Repeat the operation for each idle states. And in order to make it as much accurate as possible, set the program affinity on a CPU and isolate this one by preventing other processes to be scheduled on and migrate the interrupts on the other CPUs. That will be all userspace code, no? -- <http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs Follow Linaro: <http://www.facebook.com/pages/Linaro> Facebook | <http://twitter.com/#!/linaroorg> Twitter | <http://www.linaro.org/linaro-blog/> Blog
