On Thu, 25 Jul 2024 09:46:48 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 > > Fernando Guallini has updated the pull request with a new target base due to > a merge or a rebase. The incremental webrev excludes the unrelated changes > brought in by the merge/rebase. The pull request contains eight additional > commits since the last revision: > > - converted to automated test > - Merge branch 'master' into 8336240 > - adding back the validation to avoid dividing by zero > - byter per microsec > - use microseconds as time unit > - remove unused imports > - tiny refactor > - avoid dividing by zero Marked as reviewed by wetmore (Reviewer). ------------- PR Review: https://git.openjdk.org/jdk/pull/20135#pullrequestreview-2200590277
