GetPrimitiveArrayCritical vs GetByteArrayRegion: 140x slow-down using -Xcheck:jni and java.util.zip.DeflaterOutputStream

[Alan Bateman]

On 05/03/2018 06:33, David Holmes wrote:
> <swapped jdk-dev for core-libs-dev>
>
> Hi Ian,
>
> Do you run with -Xcheck:jni in production mode because you load 
> unknown native code libraries? It's mainly intended as a diagnostic 
> option to turn on if you encounter a possible JNI problem.
It does unusual to be running with -Xcheck:jni in a performance critical 
environment. I would expect to see-Xcheck:jni when developing or 
maintaining a library that uses JNI and drop the option the code has 
been fulling tested.

Lots of good work was done in JDK 9 to replace the ZipFile 
implementation with a Java implementation and it would be good to get 
some results with a re-write of Inflater and Deflater. It would need 
lots of testing, including startup. We would need have a dependency on 
libz of course as it is needed by the VM to deflate entries in the 
jimage container (when they are compressed) or access JAR files on the 
boot class path.

-Alan