On Wed, 16 Nov 2022 16:57:14 GMT, Mark Powers <mpow...@openjdk.org> wrote:
>> I would like a review of an update to the GCM code. A recent report showed >> that GCM memory usage for TLS was very large. This was a result of in-place >> buffers, which TLS uses, and how the code handled the combined intrinsic >> method during decryption. A temporary buffer was used because the combined >> intrinsic does gctr before ghash which results in a bad tag. The fix is to >> not use the combined intrinsic during in-place decryption and depend on the >> individual GHASH and CounterMode intrinsics. Direct ByteBuffers are not >> affected as they are not used by the intrinsics directly. >> >> The reduction in the memory usage boosted performance back to where it was >> before despite using slower intrinsics (gctr & ghash individually). The >> extra memory allocation for the temporary buffer out-weighted the faster >> intrinsic. >> >> >> JDK 17: 122913.554 ops/sec >> JDK 19: 94885.008 ops/sec >> Post fix: 122735.804 ops/sec >> >> There is no regression test because this is a memory change and test >> coverage already existing. > > src/java.base/share/classes/com/sun/crypto/provider/GaloisCounterMode.java > line 592: > >> 590: >> 591: int len = 0; >> 592: // Loop if input length is greater than the SPLIT_LEN > > comment doesn't add anything not already obvious from the code yeah.. probably right > src/java.base/share/classes/com/sun/crypto/provider/GaloisCounterMode.java > line 694: > >> 692: int originalOutOfs = 0; >> 693: >> 694: // True if op is in-place array decryption with the input & >> output > > // Setting `inPlaceArray` to true turns off combined intrinsic processing. yeah that's better ------------- PR: https://git.openjdk.org/jdk/pull/11121
