Integrated: 8259498: Reduce overhead of MD5 and SHA digests

Claes Redestad redestad at openjdk.java.net
Wed Jan 20 23:48:55 UTC 2021


On Sun, 20 Dec 2020 20:27:03 GMT, Claes Redestad <redestad at openjdk.org> wrote:

> - The MD5 intrinsics added by [JDK-8250902](https://bugs.openjdk.java.net/browse/JDK-8250902) shows that the `int[] x` isn't actually needed. This also applies to the SHA intrinsics from which the MD5 intrinsic takes inspiration
> - Using VarHandles we can simplify the code in `ByteArrayAccess` enough to make it acceptable to use inline and replace the array in MD5 wholesale. This improves performance both in the presence and the absence of the intrinsic optimization.
> - Doing the exact same thing in the SHA impls would be unwieldy (64+ element arrays), but allocating the array lazily gets most of the speed-up in the presence of an intrinsic while being neutral in its absence.
> 
> Baseline:
>                               (digesterName)  (length)    Cnt     Score      Error   Units
> MessageDigests.digest                                MD5        16     15  2714.307 ±   21.133  ops/ms
> MessageDigests.digest                                MD5      1024     15   318.087 ±    0.637  ops/ms
> MessageDigests.digest                              SHA-1        16     15  1387.266 ±   40.932  ops/ms
> MessageDigests.digest                              SHA-1      1024     15   109.273 ±    0.149  ops/ms
> MessageDigests.digest                            SHA-256        16     15   995.566 ±   21.186  ops/ms
> MessageDigests.digest                            SHA-256      1024     15    89.104 ±    0.079  ops/ms
> MessageDigests.digest                            SHA-512        16     15   803.030 ±   15.722  ops/ms
> MessageDigests.digest                            SHA-512      1024     15   115.611 ±    0.234  ops/ms
> MessageDigests.getAndDigest                          MD5        16     15  2190.367 ±   97.037  ops/ms
> MessageDigests.getAndDigest                          MD5      1024     15   302.903 ±    1.809  ops/ms
> MessageDigests.getAndDigest                        SHA-1        16     15  1262.656 ±   43.751  ops/ms
> MessageDigests.getAndDigest                        SHA-1      1024     15   104.889 ±    3.554  ops/ms
> MessageDigests.getAndDigest                      SHA-256        16     15   914.541 ±   55.621  ops/ms
> MessageDigests.getAndDigest                      SHA-256      1024     15    85.708 ±    1.394  ops/ms
> MessageDigests.getAndDigest                      SHA-512        16     15   737.719 ±   53.671  ops/ms
> MessageDigests.getAndDigest                      SHA-512      1024     15   112.307 ±    1.950  ops/ms
> 
> GC:
> MessageDigests.getAndDigest:·gc.alloc.rate.norm      MD5        16     15   312.011 ±    0.005    B/op
> MessageDigests.getAndDigest:·gc.alloc.rate.norm    SHA-1        16     15   584.020 ±    0.006    B/op
> MessageDigests.getAndDigest:·gc.alloc.rate.norm  SHA-256        16     15   544.019 ±    0.016    B/op
> MessageDigests.getAndDigest:·gc.alloc.rate.norm  SHA-512        16     15  1056.037 ±    0.003    B/op
> 
> Target:
> Benchmark                                 (digesterName)  (length)    Cnt     Score      Error   Units
> MessageDigests.digest                                MD5        16     15  3134.462 ±   43.685  ops/ms
> MessageDigests.digest                                MD5      1024     15   323.667 ±    0.633  ops/ms
> MessageDigests.digest                              SHA-1        16     15  1418.742 ±   38.223  ops/ms
> MessageDigests.digest                              SHA-1      1024     15   110.178 ±    0.788  ops/ms
> MessageDigests.digest                            SHA-256        16     15  1037.949 ±   21.214  ops/ms
> MessageDigests.digest                            SHA-256      1024     15    89.671 ±    0.228  ops/ms
> MessageDigests.digest                            SHA-512        16     15   812.028 ±   39.489  ops/ms
> MessageDigests.digest                            SHA-512      1024     15   116.738 ±    0.249  ops/ms
> MessageDigests.getAndDigest                          MD5        16     15  2314.379 ±  229.294  ops/ms
> MessageDigests.getAndDigest                          MD5      1024     15   307.835 ±    5.730  ops/ms
> MessageDigests.getAndDigest                        SHA-1        16     15  1326.887 ±   63.263  ops/ms
> MessageDigests.getAndDigest                        SHA-1      1024     15   106.611 ±    2.292  ops/ms
> MessageDigests.getAndDigest                      SHA-256        16     15   961.589 ±   82.052  ops/ms
> MessageDigests.getAndDigest                      SHA-256      1024     15    88.646 ±    0.194  ops/ms
> MessageDigests.getAndDigest                      SHA-512        16     15   775.417 ±   56.775  ops/ms
> MessageDigests.getAndDigest                      SHA-512      1024     15   112.904 ±    2.014  ops/ms
> 
> GC
> MessageDigests.getAndDigest:·gc.alloc.rate.norm      MD5        16     15   232.009 ±    0.006    B/op
> MessageDigests.getAndDigest:·gc.alloc.rate.norm    SHA-1        16     15   584.021 ±    0.001    B/op
> MessageDigests.getAndDigest:·gc.alloc.rate.norm  SHA-256        16     15   272.012 ±    0.015    B/op
> MessageDigests.getAndDigest:·gc.alloc.rate.norm  SHA-512        16     15   400.017 ±    0.019    B/op
> 
> For the `digest` micro digesting small inputs is faster with all algorithms, ranging from ~1% for SHA-512 up to ~15% for MD5. The gain stems from not allocating and reading into a temporary buffer once outside of the intrinsic. SHA-1 does not see a statistically gain because the intrinsic is disabled by default on my HW.
> 
> For the `getAndDigest` micro - which tests `MessageDigest.getInstance(..).digest(..)` there are similar gains with this patch. The interesting aspect here is verifying the reduction in allocations per operation when there's an active intrinsic (again, not for SHA-1). JDK-8259065 (#1933) reduced allocations on each of these with 144B/op, which means allocation pressure for SHA-512 is down two thirds from 1200B/op to 400B/op in this contrived test.
> 
> I've verified there are no regressions in the absence of the intrinsic - which the SHA-1 numbers here help show.

This pull request has now been integrated.

Changeset: 35c9da70
Author:    Claes Redestad <redestad at openjdk.org>
URL:       https://git.openjdk.java.net/jdk/commit/35c9da70
Stats:     655 lines in 8 files changed: 79 ins; 350 del; 226 mod

8259498: Reduce overhead of MD5 and SHA digests

Reviewed-by: valeriep

-------------

PR: https://git.openjdk.java.net/jdk/pull/1855


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