[aarch64-port-dev ] RFR: 8217368: AArch64: C2 recursive stack locking optimisation not triggered

Nick Gasson (Arm Technology China) Nick.Gasson at arm.com
Tue Jan 22 10:15:34 UTC 2019

Hi Andrew

On 22/01/2019 17:36, Andrew Haley wrote:
> Does any of the above stress test  recursive locking in the presence of many threads?

I can't immediately find anything in jcstress that does this (although I 
might not be looking in the right place).

If you do:

make test TEST="micro:LockUnlock.testRecursiveSynchronizationNoBias" 

It will run that recursive JMH case with 10 threads. In this case the 
lock will be inflated and as we don't have a fast-path for 
recursive-monitor we will call into the runtime for each recursive 
monitorenter/exit. The JMH test isn't checking for correctness but we at 
least don't hit any assertions in a fastdebug build.


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