Thanks Mandy.
dl
On 12/17/18 2:55 PM, Mandy Chung wrote:
This looks okay to me.
Mandy
On 12/14/18 4:59 PM, [email protected] wrote:
https://bugs.openjdk.java.net/browse/JDK-8214583
http://cr.openjdk.java.net/~dlong/8214583/webrev
This change includes two new regression test that demonstrate the
problem, and a fix that allows the tests
to pass.
The problem happens when the JIT compiler's escape analysis
eliminates the allocation of the AccessControlContext object passed
to doPrivileged. The compiler thinks this is safe because it does
not see that the object "escapes". However, getContext needs to be
able to find the object using a stack walk, so we need a way to tell
the compiler that it does indeed escape. To do this we pass the
value to a native method that does nothing.
Microbenchmark results:
jdk12-b18:
Benchmark Mode Cnt Score Error Units
DoPrivileged.test avgt 25 255.626 ± 6.446 ns/op
DoPrivileged.testInline avgt 25 250.968 ± 4.975 ns/op
jdk12-b19:
Benchmark Mode Cnt Score Error Units
DoPrivileged.test avgt 25 5.689 ± 0.001 ns/op
DoPrivileged.testInline avgt 25 2.765 ± 0.001 ns/op
this fix:
Benchmark Mode Cnt Score Error Units
DoPrivileged.test avgt 25 5.020 ± 0.001 ns/op
DoPrivileged.testInline avgt 25 2.774 ± 0.025 ns/op
dl
