RFR: JDK-8211727: Adjust default concurrency settings for running tests on Sparc

[Tim Bell]

Erik:

Looks good.  Thanks.

Tim

> I didn't know. Updated references to SPARC.
>
> http://cr.openjdk.java.net/~erikj/8211727/webrev.02/
>
> /Erik
>
> On 2018-11-13 14:10, Tim Bell wrote:
>> Erik:
>>
>> One nit: for trademark purposes SPARC is used in upper case [1].
>>
>> Looks good otherwise.
>>
>> Tim
>>
>> [1] Aside from appearing lowercase in URLs, it seems:
>>     https://sparc.org/trademark-usage-guide
>>     https://www.oracle.com/servers/sparc/
>>
>>
>>> This patch changes the formula for default test concurrency in
>>> RunTest.gmk. The current formula is:
>>>
>>> min(cpus/2, 12)
>>>
>>> This seems to work well enough on the x64 machines we currently run our
>>> tests on, but less so for Sparc. I have now run rather extensive testing
>>> in our lab and have come up with a new formula that provides much better
>>> test reliability while preserving as much test throughput as possible.
>>> The new formula is cpus/4 for sparcs with up to 16 cpus and cpus/5 for
>>> larger machines. For non Sparc it's still cpus/2 and I've removed the
>>> cap for all.
>>>
>>> In addition to this, since Sparc generally have lower per thread
>>> performance, at least when running JDK tests, I have bumped the default
>>> timeout factor from 4 to 8 for Sparc.
>>>
>>> With these defaults, we were able to remove a lot of special cases for
>>> Sparc in other parts of our configurations and I was able to get clean
>>> runs of all the lower tiers of testing, on each of our machine classes
>>> in the lab.
>>>
>>> In addition to this, the test
>>> compiler/jsr292/ContinuousCallSiteTargetChange.java, which had its
>>> timeout increased in JDK-8212028, no longer needs an increased timeout
>>> with the new defaults.
>>>
>>> Bug: https://bugs.openjdk.java.net/browse/JDK-8211727
>>>
>>> Webrev: http://cr.openjdk.java.net/~erikj/8211727/webrev.01/
>>>
>>> /Erik
>>
>>