Description for scheduling policy switch trace.

docs/data/withSpsEnabled/SchedulingPolicySwitchTrace.md

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+# Scheduling Policy Switch Trace
+
+Every time _Elektron_ switches to a different scheduling policy, the name of the scheduling policy and the time at which the switch took place is logged.
+
+The logs are written to a file named _\<logFilePrefix\>\_\<timestamp\>_schedPolSwitch.log_, where
+* _logFilePrefix_ is the prefix provided using the `-logPrefix` option.
+* _timestamp_ corresponds to the time when _Elektron_ was run.
+
+The format of the data logged is as shown below.
+```
+<yyyy/mm/dd> <hh:mm:ss> <scheduling policy name>
+```
+
+_Note: The names of the scheduling policies can be found [here](https://gitlab.com/spdf/elektron/blob/master/schedulers/store.go#L14)_
+