Passing time factor to tests run under jtreg

[David Holmes]

Hi Gary,

On 16/11/2011 6:14 AM, Gary Adams wrote:
> I've been scanning a number of the slow machine test
> bugs that are reported and wanted to check to see if
> anyone has looked into time dependencies in the regression
> tests previously. From what I've been able to learn so far
> individual bugs can use the "timeout" parameter to indicate to
> the test harness an expected time to run.
>
> The test harness has command line arguments where it can
> filter out tests that take too long (timelimit) or can apply a
> multiplier to
> to the timeout when conditions are known to slow down the process
> (timeoutFactor). e.g. 8X for a slow machine or running with -Xcomp
>
> I see that there are some wrappers that can be applied around running
> a particular test to allow processing before main(). Could this mechanism
> be exploited so the harness command line options could be made known
> to the time dependent tests as command line arguments or as system
> properties?
>
> My thought is the current timeout granularity is too large and only applies
> to the full test execution. If a test knew that a timeoutFactor was to
> be applied,
> it could internally adjust the time dependent delays appropriately. e.g.
> not every sleep(), await(), join() with timeouts would need the
> timeoutFactor applied.

I don't quite get what you mean about the timeouts applied to sleeps, 
awaits etc. Depending on the test some of these are delays (eg sleep is 
usually used this way) because it may not be feasible (or even possible) 
to coordinate the threads directly; while others (await, wait etc) are 
actual timeouts - if they expire it is an error because something 
appears to have gone wrong somewhere (of course this can be wrong 
because the timeout was too short for a given situation).

As many of these tests have evolved along with the testing 
infrastructure it isn't always very clear who has responsibility for 
programming defensive timeouts. And many tests are designed to be run 
stand-alone or under a test harness, where exceptions due to timeouts 
are preferable to hangs.

Further, while we can add a scale factor for known retarding factors - 
like Xcomp - there's no general way to assess the target machine 
capability (# cores, speed) and load, as it may impact a given test. And 
historically there has been a lack of resources to investigate and solve 
these issues.

Cheers,
David

> Before any test could be updated the information would need to be available
> from the test context.
>
> Any feedback/pointers appreciated!
>
>
> See
> timeoutFactorArg
> jtreg/src/share/classes/com/sun/javatest/regtest/Main.java
> runOtherJVM()
> jtreg/src/share/classes/com/sun/javatest/regtest/MainAction.java
> maxTimeoutValue
> jtreg/src/share/classes/com/sun/javatest/regtest/RegressionParameters.java
>
>