RFR(XS): [TEST] add test to verify EnableTrace works

[David Holmes]

Hi Liu Xin,

On 4/09/2018 7:45 PM, David Holmes wrote:
> On 4/09/2018 10:12 AM, Liu, Xin wrote:
>> Hi, David,
>> Thank you for reviewing it.
>>
>> If you are using OracleJDK, it won't have any output. OracleJDK 
>> doesn't suffer from crash. I guess It suppress events unconditionally.
>> For JDK8u, "-XX:+EnableTracing -version" will dump some events.  It 
>> won't crash if it has this patch 
>> http://hg.openjdk.java.net/jdk8u/jdk8u-dev/hotspot/rev/80ee2541504e
>> The attachment is the output.
> 
> If the Oracle JDK doesn't produce any output then this test will fail on 
> the Oracle JDK so can't be accepted in current form.
> 
> There's something going on with EnableTracing that I'm not 
> understanding. I'll try to take a closer look tomorrow ( was on a day 
> off today).

Okay ... the Oracle JDK replaces the OpenJDK tracing facility with JFR 
which completely ignores the EnableTracing flag.

If the test is simply verifying that -XX:+EnableTracing doesn't crash 
then it can reduce to just:

/*
  * @test
  * @summary Ensure -XX:+EnableTracing doesn't crash
  * @run main/othervm -XX:+EnableTracing TestEnableTracing
  */
public class TestEnableTracing {
     public static void main(String[] args) {
     }
}

If you want to actually verify some of the trace output then you will 
need to guard the shouldMatch/Contain statements with something like:

if (output.getOutput().contains("OpenJDK")) {
...
}

I don't think there is a direct way to ensure the test is only executed 
on an OpenJDK binary.

Thanks,
David

> Thanks,
> David
> 
>>
>> Output of jtreg
>> ###
>> # Running suite single for openJDK
>> # Results are available in build/brazil-open-single-tests
>> ###
>> Directory "build/JTwork" not found: creating
>> Passed: runtime/EnableTracing/TestEnableTracing.java
>> Test results: passed: 1
>> Report written to 
>> /local/home/xxinliu/ws-openjdk8/build/OpenJDK8CompatibilityTests/OpenJDK8CompatibilityTests-1.0/RHEL5_64/DEV.STD.PTHREAD/build/brazil-open-single-tests/html/report.html 
>>
>> Results written to 
>> /local/home/xxinliu/ws-openjdk8/build/OpenJDK8CompatibilityTests/OpenJDK8CompatibilityTests-1.0/RHEL5_64/DEV.STD.PTHREAD/build/JTwork 
>>
>>
>> Thanks,
>> --lx
>>
>>
>> On 9/2/18, 10:01 PM, "David Holmes" <david.holmes at oracle.com> wrote:
>>
>>      Hi,
>>      On 25/08/2018 2:35 AM, Liu, Xin wrote:
>>      > Hi, hotspot-Runtime Developers,
>>      >
>>      > Could you review this small tests?
>>      > It adds a new test to verify +EnableTracing works for jdk8u.
>>      I don't see any output produced with just "-XX:+EnableTracing 
>> -version". ??
>>        >
>>      
>> /java/re/jdk/8u172/promoted/latest/binaries/linux-amd64/fastdebug/bin/java 
>>
>>      -XX:+EnableTracing -version
>>      java version "1.8.0_172-fastdebug"
>>      Java(TM) SE Runtime Environment (build 1.8.0_172-fastdebug-b35)
>>      Java HotSpot(TM) 64-Bit Server VM (build 25.172-b35-fastdebug, 
>> mixed mode)
>>      Thanks,
>>      David
>>      > BUG:  https://bugs.openjdk.java.net/browse/JDK-8209863
>>      > WEBREV: http://cr.openjdk.java.net/~phh/8209863/webrev.00/
>>      >
>>      > Thanks,
>>      > -lx
>>      >
>>