NativePRNG SecureRandom doesn’t scale with number of threads. The performance starts dropping as we increase the number of threads. Even going from 1 thread to 2 threads shows significant drop. The bottleneck is the singleton RandomIO instance. Making the RandomIO ThreadLocal helps in removing this bottleneck.
Here are the jmh thrpt ops/s data for SecureRandomBench.nextBytes, algorithm=NativePRNGNonBlocking, datasize=64, notshared: <html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:x="urn:schemas-microsoft-com:office:excel" xmlns="http://www.w3.org/TR/REC-html40";> <head> <meta name=ProgId content=Excel.Sheet> <meta name=Generator content="Microsoft Excel 15"> <link id=Main-File rel=Main-File href="file:///C:/Users/xbzhang/AppData/Local/Temp/msohtmlclip1/01/clip.htm"> <link rel=File-List href="file:///C:/Users/xbzhang/AppData/Local/Temp/msohtmlclip1/01/clip_filelist.xml"> </head> <body link="#0563C1" vlink="#954F72"> #threads | singleton RandomIO | ThreadLocal RandomIO -- | -- | -- 1 | 1269133 | 1279088 2 | 862923 | 1362066 3 | 819734 | 1630522 4 | 809128 | 1614500 5 | 821514 | 1594965 6 | 808795 | 1545045 7 | 783050 | 1499388 8 | 787236 | 1470004 </body> </html> ------------- Commit messages: - cleanup - removed print statements - Initial change with Sandhya's patch Changes: https://git.openjdk.org/jdk/pull/11069/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=11069&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8296746 Stats: 30 lines in 1 file changed: 3 ins; 0 del; 27 mod Patch: https://git.openjdk.org/jdk/pull/11069.diff Fetch: git fetch https://git.openjdk.org/jdk pull/11069/head:pull/11069 PR: https://git.openjdk.org/jdk/pull/11069
