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Physical Clock Synchronization

Module: Harness

Description

By default, the Faban harness will try to synchronize the clock of each system in the rig (driver and SUT) to be in sync with the master, within 10 milliseconds. This will ensure that the log records are displayed in chronologial order and avoid confusion interpreting the logs.

Note: This feature is to not to be confused with the virtual clock sync that already happens in the driver framework and happens at a much higher accuracy.

Configuration

The clock synchronization happens by default. No configuration is needed. In certain circumstances and for certain benchmarks (see the Restrictions/Limitations section, below), it is desirable to turn off the physical clock sync. This can be done by adding the fh:clockSync element under fa:runConfig in the run configuration file. This element contains a boolean value. If set to false, the clock sync will be omitted.

<fa:runConfig definition="sample.driver.WebDriver"
        xmlns="http://faban.sunsource.net/ns/fabandriver"
        xmlns:fa="http://faban.sunsource.net/ns/faban"
        xmlns:fh="http://faban.sunsource.net/ns/fabanharness">
    ....
    <fh:timeSync>false</fh:timeSync>
    ....
</fa:runConfig>

Restrictions/Limitations

There are very many circumstances the system clocks cannot be set. Mainly, if user does not have permissions to set the clock, Faban will log an error to the run log. Failure of the physical clock sync won't generally cause the run to fail and has no side-effect except for the log message just mentioned. Also the clock sync is known not to work on Windows so far and is known not to work on several virtual machine configurations that does not allow  operating system instances  to change the time.

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