Use POWER8 and POWER9 ISA enhancements to improve the performance of SHA-2. Demonstrate why achieved performance is close to optimal for the platform. Optimized implementations in the Cryptogams repository[1] may serve as useful references. Financial bounty upon completion and community acceptance of patches.
Description
Description
Revisions and Commits
Revisions and Commits
| Status | Assigned | Task | ||
|---|---|---|---|---|
| Open | jukivili | T4460 libgcrypt performance TODOs | ||
| Resolved | jukivili | T4531 PowerPC performance improvements | ||
| Resolved | jukivili | T4530 libgcrypt: POWER SHA-2 Vector Acceleration |
Event Timeline
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Please do not change the priority back without discussing this with the maintainer first. Thanks.
Comment Actions
I'll start working on new PowerPC SHA2 implementations for libgcrypt in coming weeks.
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Patches send to mailing list:
https://lists.gnupg.org/pipermail/gcrypt-devel/2019-August/004800.html
https://lists.gnupg.org/pipermail/gcrypt-devel/2019-August/004799.html
SHA256 results:
Benchmark on POWER8 ~3.8Ghz:
Before:
| nanosecs/byte mebibytes/sec cycles/byte
SHA256 | 4.17 ns/B 228.6 MiB/s 15.85 c/B
After (~1.63x faster):
| nanosecs/byte mebibytes/sec cycles/byte
SHA256 | 2.55 ns/B 373.9 MiB/s 9.69 c/B
For comparison, OpenSSL 1.1.1b (~2.4% slower):
| nanosecs/byte mebibytes/sec cycles/byte
SHA256 | 2.61 ns/B 364.8 MiB/s 9.93 c/B
Benchmark on POWER9 ~3.8Ghz:
Before:
| nanosecs/byte mebibytes/sec cycles/byte
SHA256 | 3.23 ns/B 295.6 MiB/s 12.26 c/B
After (~1.03x faster):
| nanosecs/byte mebibytes/sec cycles/byte
SHA256 | 3.11 ns/B 306.8 MiB/s 11.81 c/B
For comparison, OpenSSL 1.1.1b (~6.6% faster):
| nanosecs/byte mebibytes/sec cycles/byte
SHA256 | 2.91 ns/B 327.5 MiB/s 11.07 c/BSHA512 results:
Benchmark on POWER8 ~3.8Ghz:
Before:
| nanosecs/byte mebibytes/sec cycles/byte
SHA512 | 3.47 ns/B 274.6 MiB/s 13.20 c/B
After (~2.08x faster):
| nanosecs/byte mebibytes/sec cycles/byte
SHA512 | 1.66 ns/B 573.1 MiB/s 6.32 c/B
For comparison, OpenSSL 1.1.1b (~1.6% faster):
| nanosecs/byte mebibytes/sec cycles/byte
SHA512 | 1.64 ns/B 582.2 MiB/s 6.22 c/B
Benchmark on POWER9 ~3.8Ghz:
Before:
| nanosecs/byte mebibytes/sec cycles/byte
SHA512 | 2.65 ns/B 359.6 MiB/s 10.08 c/B
After (~1.33x faster):
| nanosecs/byte mebibytes/sec cycles/byte
SHA512 | 1.99 ns/B 479.2 MiB/s 7.56 c/B
For comparison, OpenSSL 1.1.1b (~9.4% faster):
| nanosecs/byte mebibytes/sec cycles/byte
SHA512 | 1.82 ns/B 524.4 MiB/s 6.91 c/BI have not been able to get Altivec/VSX intrinsic implementation to work fast on POWER9. Appears that SHA2 vector acceleration gives diminishing returns on POWER9. For example, OpenSSL assembly vshasigma(w|d) implementations are only 6 to 10% faster than optimized non-vector C implementation provided here, which is within what is expected speed-up if these C implementations would be turned into assembly implementations.
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PowerPC SHA-256 and SHA-512 implementations with little bit more tuning committed. Most notably, SHA-512 on POWER8 now gives similar performance to OpenSSL:
Benchmark on POWER8 ~3.8Ghz:
Before:
| nanosecs/byte mebibytes/sec cycles/byte
SHA512 | 3.47 ns/B 274.6 MiB/s 13.20 c/B
After (~2.1x faster):
| nanosecs/byte mebibytes/sec cycles/byte
SHA512 | 1.64 ns/B 581.8 MiB/s 6.23 c/B
For comparison, OpenSSL 1.1.1b (~same):
| nanosecs/byte mebibytes/sec cycles/byte
SHA512 | 1.64 ns/B 582.2 MiB/s 6.22 c/B