Integrated: 8298865: Excessive memory allocation in CipherOutputStream AEAD decryption

[Daniel Jeliński]

On Thu, 15 Dec 2022 14:05:43 GMT, Daniel Jeliński <djelinski at openjdk.org> wrote:

> This patch modifies `CipherOutputStream` to avoid pointless memory allocations when decrypting data using AEAD ciphers. This is related to #11597, which fixed a similar issue in `CipherInputStream`.
> 
> `Cipher.update` does not output any data when doing AEAD decryption; all data is buffered, and is later returned in one shot from `doFinal`. `Cipher.getOutputSize` returns the buffer size required by `doFinal`, which increases after every `update`, triggering new allocation in `ensureCapacity`.
> 
> This patch addresses the issue by calling the `update` overload that returns the output buffer until one of the update calls returns some data. When that happens, we know that the cipher does not buffer everything until `doFinal`, and revert to original behavior.
> 
> This PR adds a new benchmark for AES/GCM encryption and decryption using `CipherOutputStream`.
> 
> Benchmark results before:
> 
> Benchmark                         (dataSize)  (keyLength)  (provider)   Mode  Cnt       Score      Error  Units
> AESGCMCipherOutputStream.decrypt       16384          128              thrpt   40   27949,624 ±  301,408  ops/s
> AESGCMCipherOutputStream.decrypt     1048576          128              thrpt   40      20,730 ±    0,875  ops/s
> AESGCMCipherOutputStream.encrypt       16384          128              thrpt   40  175358,641 ± 4235,808  ops/s
> AESGCMCipherOutputStream.encrypt     1048576          128              thrpt   40    2588,111 ±   35,469  ops/s
> 
> 
> after:
> 
> Benchmark                         (dataSize)  (keyLength)  (provider)   Mode  Cnt       Score      Error  Units
> AESGCMCipherOutputStream.decrypt       16384          128              thrpt   40   69644,217 ± 1081,032  ops/s
> AESGCMCipherOutputStream.decrypt     1048576          128              thrpt   40     949,667 ±    9,431  ops/s
> AESGCMCipherOutputStream.encrypt       16384          128              thrpt   40  173144,038 ± 3279,149  ops/s
> AESGCMCipherOutputStream.encrypt     1048576          128              thrpt   40    2514,840 ±   87,935  ops/s

This pull request has now been integrated.

Changeset: 36de61c4
Author:    Daniel Jeliński <djelinski at openjdk.org>
URL:       https://git.openjdk.org/jdk/commit/36de61c460d7038019294293143e420dfcce2936
Stats:     159 lines in 3 files changed: 152 ins; 0 del; 7 mod

8298865: Excessive memory allocation in CipherOutputStream AEAD decryption

Reviewed-by: valeriep, ascarpino

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PR: https://git.openjdk.org/jdk/pull/11693