Delete aes_ctrby8_avx-x86_64.S and add a new assembly file
aes-ctr-avx-x86_64.S which follows a similar approach to
aes-xts-avx-x86_64.S in that it uses a "template" to provide AESNI+AVX,
VAES+AVX2, VAES+AVX10/256, and VAES+AVX10/512 code, instead of just
AESNI+AVX. Wire it up to the crypto API accordingly.
This greatly improves the performance of AES-CTR and AES-XCTR on
VAES-capable CPUs, with the best case being AMD Zen 5 where an over 230%
increase in throughput is seen on long messages. Performance on
non-VAES-capable CPUs remains about the same, and the non-AVX AES-CTR
code (aesni_ctr_enc) is also kept as-is for now. There are some slight
regressions (less than 10%) on some short message lengths on some CPUs;
these are difficult to avoid, given how the previous code was so heavily
unrolled by message length, and they are not particularly important.
Detailed performance results are given in the tables below.
Both CTR and XCTR support is retained. The main loop remains
8-vector-wide, which differs from the 4-vector-wide main loops that are
used in the XTS and GCM code. A wider loop is appropriate for CTR and
XCTR since they have fewer other instructions (such as vpclmulqdq) to
interleave with the AES instructions.
Similar to what was the case for AES-GCM, the new assembly code also has
a much smaller binary size, as it fixes the excessive unrolling by data
length and key length present in the old code. Specifically, the new
assembly file compiles to about 9 KB of text vs. 28 KB for the old file.
This is despite 4x as many implementations being included.
The tables below show the detailed performance results. The tables show
percentage improvement in single-threaded throughput for repeated
encryption of the given message length; an increase from 6000 MB/s to
12000 MB/s would be listed as 100%. They were collected by directly
measuring the Linux crypto API performance using a custom kernel module.
The tested CPUs were all server processors from Google Compute Engine
except for Zen 5 which was a Ryzen 9 9950X desktop processor.
Table 1: AES-256-CTR throughput improvement,
CPU microarchitecture vs. message length in bytes:
| 16384 | 4096 | 4095 | 1420 | 512 | 500 |
---------------------+-------+-------+-------+-------+-------+-------+
AMD Zen 5 | 232% | 203% | 212% | 143% | 71% | 95% |
Intel Emerald Rapids | 116% | 116% | 117% | 91% | 78% | 79% |
Intel Ice Lake | 109% | 103% | 107% | 81% | 54% | 56% |
AMD Zen 4 | 109% | 91% | 100% | 70% | 43% | 59% |
AMD Zen 3 | 92% | 78% | 87% | 57% | 32% | 43% |
AMD Zen 2 | 9% | 8% | 14% | 12% | 8% | 21% |
Intel Skylake | 7% | 7% | 8% | 5% | 3% | 8% |
| 300 | 200 | 64 | 63 | 16 |
---------------------+-------+-------+-------+-------+-------+
AMD Zen 5 | 57% | 39% | -9% | 7% | -7% |
Intel Emerald Rapids | 37% | 42% | -0% | 13% | -8% |
Intel Ice Lake | 39% | 30% | -1% | 14% | -9% |
AMD Zen 4 | 42% | 38% | -0% | 18% | -3% |
AMD Zen 3 | 38% | 35% | 6% | 31% | 5% |
AMD Zen 2 | 24% | 23% | 5% | 30% | 3% |
Intel Skylake | 9% | 1% | -4% | 10% | -7% |
Table 2: AES-256-XCTR throughput improvement,
CPU microarchitecture vs. message length in bytes:
| 16384 | 4096 | 4095 | 1420 | 512 | 500 |
---------------------+-------+-------+-------+-------+-------+-------+
AMD Zen 5 | 240% | 201% | 216% | 151% | 75% | 108% |
Intel Emerald Rapids | 100% | 99% | 102% | 91% | 94% | 104% |
Intel Ice Lake | 93% | 89% | 92% | 74% | 50% | 64% |
AMD Zen 4 | 86% | 75% | 83% | 60% | 41% | 52% |
AMD Zen 3 | 73% | 63% | 69% | 45% | 21% | 33% |
AMD Zen 2 | -2% | -2% | 2% | 3% | -1% | 11% |
Intel Skylake | -1% | -1% | 1% | 2% | -1% | 9% |
| 300 | 200 | 64 | 63 | 16 |
---------------------+-------+-------+-------+-------+-------+
AMD Zen 5 | 78% | 56% | -4% | 38% | -2% |
Intel Emerald Rapids | 61% | 55% | 4% | 32% | -5% |
Intel Ice Lake | 57% | 42% | 3% | 44% | -4% |
AMD Zen 4 | 35% | 28% | -1% | 17% | -3% |
AMD Zen 3 | 26% | 23% | -3% | 11% | -6% |
AMD Zen 2 | 13% | 24% | -1% | 14% | -3% |
Intel Skylake | 16% | 8% | -4% | 35% | -3% |
Signed-off-by: 
Eric Biggers <ebiggers@google.com>
Reviewed-by: 
Ard Biesheuvel <ardb@kernel.org>
Tested-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: 
Herbert Xu <herbert@gondor.apana.org.au>
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