RFR: 8330108: Increase CipherInputStream buffer size

[Sean Mullan]

On Fri, 12 Apr 2024 15:34:01 GMT, Oli Gillespie <ogillespie at openjdk.org> wrote:

> Increase buffer size in CipherInputStream from 512 bytes to 8192 bytes.
> 
> I have seen applications where this small buffer size significantly reduces throughput, and I've even seen applications which use reflection to modify the buffer size to work around the issue.
> 
> Using the existing `AESGCMCipherInputStream` benchmark, we can see that 8192 performs better in all the explored cases than 512. Sometimes other sizes beat 8192, but it seems a good compromise of performance across encrypt/decrypt and memory usage, plus it's in line with other JDK classes like ChannelInputStream and FileInputStream.
> 
> ### Benchmark results
> 
> 
> make test TEST=micro:org.openjdk.bench.javax.crypto.full.AESGCMCipherInputStream
> 
> 
> These are the results just comparing 512 and 8192. 8192 wins substantially for encrypt of both data sizes, and wins noticeably for small decrypt data size, while remaining roughly equal for large decrypt data size (why are the error bars so wide there...?)
> 
> 
>  (benchmark)  (dataSize)        Score      Error  Units
> Before: (buffer size 512 bytes)
>    decrypt         16384    41800.053 +-  674.761  ops/s
>    decrypt       1048576      219.218 +- 4509.696  ops/s
>    encrypt         16384    59481.957 +- 2297.546  ops/s
>    encrypt       1048576     1030.822 +-   48.273  ops/s
> After: (buffer size 8192 bytes)
>    decrypt         16384    45023.512 +-  351.284  ops/s
>    decrypt       1048576      217.506 +- 4498.711  ops/s
>    encrypt         16384    71678.424 +- 1731.105  ops/s
>    encrypt       1048576     1562.457 +-   50.944  ops/s
> 
> 
> These are the full results including other candidate buffer sizes.
> 
> 
> AESGCMCipherInputStream.decrypt
>  (bufSize)  (dataSize)        Score      Error  Units
>        128       16384    36282.200 +- 3827.690  ops/s
>        512       16384    41800.053 +-  674.761  ops/s
>       2048       16384    44411.579 +- 2452.429  ops/s
>       8192       16384    45023.512 +-  351.284  ops/s
>      32768       16384    51004.362 +- 3147.855  ops/s
>     131702       16384    32111.911 +-  766.159  ops/s
>        128     1048576      200.096 +- 3972.338  ops/s
>        512     1048576      219.218 +- 4509.696  ops/s
>       2048     1048576      224.036 +- 4582.988  ops/s
>       8192     1048576      217.506 +- 4498.711  ops/s
>      32768     1048576      205.818 +- 4233.473  ops/s
>     131702     1048576      247.852 +- 5533.972  ops/s
> 
> 
> AESGCMCipherInputStream.encrypt
>  (bufSize)  (dataSize)        Score      Error  Units
>        128       16384    38352.717 +- 5030.671  o...

Please don't integrate until a Reviewer from the Security Group has reviewed this. Thanks.

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PR Comment: https://git.openjdk.org/jdk/pull/18763#issuecomment-2052072764