Integrated: 8336240: Test com/sun/crypto/provider/Cipher/DES/PerformanceTest.java fails with java.lang.ArithmeticException

[Fernando Guallini]

On Thu, 11 Jul 2024 09:51:10 GMT, Fernando Guallini <fguallini at 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 <fguallini at openjdk.org>
Committer: Bradford Wetmore <wetmore at 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

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PR: https://git.openjdk.org/jdk/pull/20135