[9] RFR(XXS): 8036091: compiler/membars/DekkerTest.java fails with -XX:CICompilerCount=1

[Aleksey Shipilev]

On 03/03/2014 02:04 PM, Roland Westrelin wrote:
> Hi Albert,
> 
>> Problem: JDK-8034775 changed the minimum number of compiler threads
>> for tiered compilation to 2, since each compiler (C1 and C2)
>> requires a separate compiler thread. The test is started with
>> -XX:CICompilerCount=1, which is illegal after JDK-8034775.
>> 
>> Solution: Remove -XX:CICompilerCount=1
> 
> But then if we run with tiered off, C2 will have more than 1 compiler
> thread which is not what the test wants for some reason. Maybe if
> tiered is on CICompilerCount=1 should make the VM silently use 1
> thread per compilers?

+1.

I missed the review of the original CICompilerCount fix which made "1"
illegal in some cases. I think there are other broken tests and/or use
cases which rely on CICompilerCount=1, e.g. printing generated assembly
without (hopefully) mixing up the output from the concurrent compiler
tests, i.e.:

$ alias java-asm
alias java-asm='java -XX:+UnlockDiagnosticVMOptions
-XX:CICompilerCount=1 -XX:+PrintCompilation -XX:+PrintInlining
-XX:+PrintAssembly'

-Aleksey