Brian Smith suggested applying vpaes-armv8's "2x" optimization to
vpaes-x86_64. The registers are a little tight (aarch64 has a whole 32
SIMD registers, while x86_64 only has 16), but it's doable with some
spills and makes vpaes much more competitive with bsaes. At small- and
medium-sized inputs, vpaes now matches bsaes. At large inputs, it's a
~10% perf hit.
bsaes is thus pulling much less weight. Losing an entire AES
implementation and having constant-time AES for SSSE3 is attractive.
Some notes:
- The fact that these are older CPUs tempers the perf hit, but CPUs
without AES-NI are still common enough to matter.
- This CL does regress CBC decrypt performance nontrivially (see below).
If this matters, we can double-up CBC decryption too. CBC in TLS is
legacy and already pays a costly Lucky13 mitigation.
- The difference between 1350 and 8192 bytes is likely bsaes AES-GCM
paying for two slow (and variable-time!) aes_nohw_encrypt
calls for EK0 and the trailing partial block. At larger inputs, those
two calls are more amortized.
- To that end, bsaes would likely be much faster on AES-GCM with smarter
use of bsaes. (Fold one-off calls above into bulk data.) Implementing
this is a bit of a nuisance though, especially considering we don't
wish to regress hwaes.
- I'd discarded the key conversion idea, but I think I did it wrong.
Benchmarks from
https://boringssl-review.googlesource.com/c/boringssl/+/33589 suggest
converting to bsaes format on-demand for large ctr32 inputs should
give the best of both worlds, but at the cost of an entire AES
implementation relative to this CL.
- ARMv7 still depends on bsaes and has no vpaes. It also has 16 SIMD
registers, so my plan is to translate it, with the same 2x
optimization, and see how it compares. Hopefully that, or some
combination of the above, will work for ARMv7.
Sandy Bridge
bsaes (before):
Did 3144750 AES-128-GCM (16 bytes) seal operations in 5016000us (626943.8 ops/sec): 10.0 MB/s
Did 2053750 AES-128-GCM (256 bytes) seal operations in 5016000us (409439.8 ops/sec): 104.8 MB/s
Did 469000 AES-128-GCM (1350 bytes) seal operations in 5015000us (93519.4 ops/sec): 126.3 MB/s
Did 92500 AES-128-GCM (8192 bytes) seal operations in 5016000us (18441.0 ops/sec): 151.1 MB/s
Did 46750 AES-128-GCM (16384 bytes) seal operations in 5032000us (9290.5 ops/sec): 152.2 MB/s
vpaes-1x (for reference, not this CL):
Did 8684750 AES-128-GCM (16 bytes) seal operations in 5015000us (1731754.7 ops/sec): 27.7 MB/s [+177%]
Did 1731500 AES-128-GCM (256 bytes) seal operations in 5016000us (345195.4 ops/sec): 88.4 MB/s [-15.6%]
Did 346500 AES-128-GCM (1350 bytes) seal operations in 5016000us (69078.9 ops/sec): 93.3 MB/s [-26.1%]
Did 61250 AES-128-GCM (8192 bytes) seal operations in 5015000us (12213.4 ops/sec): 100.1 MB/s [-33.8%]
Did 32500 AES-128-GCM (16384 bytes) seal operations in 5031000us (6459.9 ops/sec): 105.8 MB/s [-30.5%]
vpaes-2x (this CL):
Did 8840000 AES-128-GCM (16 bytes) seal operations in 5015000us (1762711.9 ops/sec): 28.2 MB/s [+182%]
Did 2167750 AES-128-GCM (256 bytes) seal operations in 5016000us (432167.1 ops/sec): 110.6 MB/s [+5.5%]
Did 474000 AES-128-GCM (1350 bytes) seal operations in 5016000us (94497.6 ops/sec): 127.6 MB/s [+1.0%]
Did 81750 AES-128-GCM (8192 bytes) seal operations in 5015000us (16301.1 ops/sec): 133.5 MB/s [-11.6%]
Did 41750 AES-128-GCM (16384 bytes) seal operations in 5031000us (8298.5 ops/sec): 136.0 MB/s [-10.6%]
Penryn
bsaes (before):
Did 958000 AES-128-GCM (16 bytes) seal operations in 1000264us (957747.2 ops/sec): 15.3 MB/s
Did 420000 AES-128-GCM (256 bytes) seal operations in 1000480us (419798.5 ops/sec): 107.5 MB/s
Did 96000 AES-128-GCM (1350 bytes) seal operations in 1001083us (95896.1 ops/sec): 129.5 MB/s
Did 18000 AES-128-GCM (8192 bytes) seal operations in 1042491us (17266.3 ops/sec): 141.4 MB/s
Did 9482 AES-128-GCM (16384 bytes) seal operations in 1095703us (8653.8 ops/sec): 141.8 MB/s
Did 758000 AES-256-GCM (16 bytes) seal operations in 1000769us (757417.5 ops/sec): 12.1 MB/s
Did 359000 AES-256-GCM (256 bytes) seal operations in 1001993us (358285.9 ops/sec): 91.7 MB/s
Did 82000 AES-256-GCM (1350 bytes) seal operations in 1009583us (81221.7 ops/sec): 109.6 MB/s
Did 15000 AES-256-GCM (8192 bytes) seal operations in 1022294us (14672.9 ops/sec): 120.2 MB/s
Did 7884 AES-256-GCM (16384 bytes) seal operations in 1070934us (7361.8 ops/sec): 120.6 MB/s
vpaes-1x (for reference, not this CL):
Did 2030000 AES-128-GCM (16 bytes) seal operations in 1000227us (2029539.3 ops/sec): 32.5 MB/s [+112%]
Did 382000 AES-128-GCM (256 bytes) seal operations in 1001949us (381256.9 ops/sec): 97.6 MB/s [-9.2%]
Did 81000 AES-128-GCM (1350 bytes) seal operations in 1007297us (80413.2 ops/sec): 108.6 MB/s [-16.1%]
Did 14000 AES-128-GCM (8192 bytes) seal operations in 1031499us (13572.5 ops/sec): 111.2 MB/s [-21.4%]
Did 7008 AES-128-GCM (16384 bytes) seal operations in 1030706us (6799.2 ops/sec): 111.4 MB/s [-21.4%]
Did 1838000 AES-256-GCM (16 bytes) seal operations in 1000238us (1837562.7 ops/sec): 29.4 MB/s [+143%]
Did 321000 AES-256-GCM (256 bytes) seal operations in 1001666us (320466.1 ops/sec): 82.0 MB/s [-10.6%]
Did 67000 AES-256-GCM (1350 bytes) seal operations in 1010359us (66313.1 ops/sec): 89.5 MB/s [-18.3%]
Did 12000 AES-256-GCM (8192 bytes) seal operations in 1072706us (11186.7 ops/sec): 91.6 MB/s [-23.8%]
Did 5680 AES-256-GCM (16384 bytes) seal operations in 1009214us (5628.1 ops/sec): 92.2 MB/s [-23.5%]
vpaes-2x (this CL):
Did 2072000 AES-128-GCM (16 bytes) seal operations in 1000066us (2071863.3 ops/sec): 33.1 MB/s [+116%]
Did 432000 AES-128-GCM (256 bytes) seal operations in 1000732us (431684.0 ops/sec): 110.5 MB/s [+2.8%]
Did 92000 AES-128-GCM (1350 bytes) seal operations in 1000580us (91946.7 ops/sec): 124.1 MB/s [-4.2%]
Did 16000 AES-128-GCM (8192 bytes) seal operations in 1016422us (15741.5 ops/sec): 129.0 MB/s [-8.8%]
Did 8448 AES-128-GCM (16384 bytes) seal operations in 1073962us (7866.2 ops/sec): 128.9 MB/s [-9.1%]
Did 1865000 AES-256-GCM (16 bytes) seal operations in 1000043us (1864919.8 ops/sec): 29.8 MB/s [+146%]
Did 364000 AES-256-GCM (256 bytes) seal operations in 1001561us (363432.7 ops/sec): 93.0 MB/s [+1.4%]
Did 77000 AES-256-GCM (1350 bytes) seal operations in 1004123us (76683.8 ops/sec): 103.5 MB/s [-5.6%]
Did 14000 AES-256-GCM (8192 bytes) seal operations in 1071179us (13069.7 ops/sec): 107.1 MB/s [-10.9%]
Did 7008 AES-256-GCM (16384 bytes) seal operations in 1074125us (6524.4 ops/sec): 106.9 MB/s [-11.4%]
Penryn, CBC mode decryption
bsaes (before):
Did 159000 AES-128-CBC-SHA1 (16 bytes) open operations in 1001019us (158838.1 ops/sec): 2.5 MB/s
Did 114000 AES-128-CBC-SHA1 (256 bytes) open operations in 1006485us (113265.5 ops/sec): 29.0 MB/s
Did 65000 AES-128-CBC-SHA1 (1350 bytes) open operations in 1008441us (64455.9 ops/sec): 87.0 MB/s
Did 17000 AES-128-CBC-SHA1 (8192 bytes) open operations in 1005440us (16908.0 ops/sec): 138.5 MB/s
vpaes (after):
Did 167000 AES-128-CBC-SHA1 (16 bytes) open operations in 1003556us (166408.3 ops/sec): 2.7 MB/s [+8%]
Did 112000 AES-128-CBC-SHA1 (256 bytes) open operations in 1005673us (111368.2 ops/sec): 28.5 MB/s [-1.7%]
Did 56000 AES-128-CBC-SHA1 (1350 bytes) open operations in 1005647us (55685.5 ops/sec): 75.2 MB/s [-13.6%]
Did 13635 AES-128-CBC-SHA1 (8192 bytes) open operations in 1020486us (13361.3 ops/sec): 109.5 MB/s [-20.9%]
Bug: 256
Change-Id: I11ed773323ec7a5ee61080c9ed9ed4761849828a
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/35364
Commit-Queue: David Benjamin <davidben@google.com>
Reviewed-by: Adam Langley <agl@google.com>
32ce6032ff