On Thu, 11 Jul 2024 09:51:10 GMT, Fernando Guallini <fguall...@openjdk.org> wrote:
> The manual test Cipher/DES/PerformanceTest.java fails with > ArithmeticException due to potential division by zero. The issue arises when > calculating the elapsed time using end - start, which could result in zero > milliseconds if start and end are identical due to the high speed of > execution. This leads to a division error in the following code snippet: > > > start = System.currentTimeMillis(); > end = System.currentTimeMillis(); > int speed = (int)((data.length * count)/(end - start)); > > This issue is easily reproducible on platforms where > System.currentTimeMillis() has low granularity, such as many versions of > Windows, end and start can be equal when obtaining System.currentTimeMillis() > if the test runs very quickly. > > The fix is to use System.nanoTime() instead, which is designed to measure > elapsed time with very high precision. This value is then converted to > microseconds so the tests can properly calculate the throughput (bytes > processed per microsecond) for the report. Example output: > > > Algorithm DataSize Rounds Bytes/microsec > DES/ECB/NoPadding 1024 100 66 > DES/ECB/NoPadding 1024 1000 50 > DES/ECB/NoPadding 8192 100 70 > DES/ECB/NoPadding 8192 1000 70 > Average: 64 This pull request has now been integrated. Changeset: 034297a6 Author: Fernando Guallini <fguall...@openjdk.org> Committer: Bradford Wetmore <wetm...@openjdk.org> URL: https://git.openjdk.org/jdk/commit/034297a6bd9bfcea7fa48792f54c84a6e976b319 Stats: 16 lines in 3 files changed: 6 ins; 5 del; 5 mod 8336240: Test com/sun/crypto/provider/Cipher/DES/PerformanceTest.java fails with java.lang.ArithmeticException Reviewed-by: wetmore ------------- PR: https://git.openjdk.org/jdk/pull/20135
