Comment by vluft | Hacker News Reader

Comment by vluft | Hacker News Reader

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followup to this now with further blake3 improvements, on a faster machine now but with sha extensions vs single-threaded blake3; blake3 is about 2.5x faster than sha256 now. (b3sum 1.5.0 vs openssl 3.0.11). b3sum is about 9x faster than sha256sum from coreutils (GNU, 9.3) which does not use the sha extensions.

  Benchmark 1: openssl sha256 /tmp/rand_1G
    Time (mean ± σ):     576.8 ms ±   3.5 ms    [User: 415.0 ms, System: 161.8 ms]
    Range (min … max):   569.7 ms … 580.3 ms    10 runs

  Benchmark 2: b3sum --num-threads 1 /tmp/rand_1G
    Time (mean ± σ):     228.7 ms ±   3.7 ms    [User: 168.7 ms, System: 59.5 ms]
    Range (min … max):   223.5 ms … 234.9 ms    13 runs

  Benchmark 3: sha256sum /tmp/rand_1G
    Time (mean ± σ):      2.062 s ±  0.025 s    [User: 1.923 s, System: 0.138 s]
    Range (min … max):    2.046 s …  2.130 s    10 runs

  Summary
    b3sum --num-threads 1 /tmp/rand_1G ran
      2.52 ± 0.04 times faster than openssl sha256 /tmp/rand_1G
      9.02 ± 0.18 times faster than sha256sum /tmp/rand_1G

> ...on a faster machine now but with sha extensions vs single-threaded blake3; blake3 is about 2.5x faster than sha256 now

But one of the sweet benefit of blake3 is that it is parallelized by default. I picked blake3 not because it's 2.5x faster than sha256 when running b3sum with "--num-threads 1" but because, with the default, it's 16x faster than sha256 (on a machine with "only" 8 cores).

And Blake3, contrarily to some other "parallelizable" hashes, give the same hash no matter if you run it with one thread or any number of threads (IIRC there are hashes which have different executables depending if you want to run the single-threaded or multi-threader version of the hash, and they give different checksums).

I tried on my machine (which is a bit slower than yours) and I get:

   990 ms openssl sha256
   331 ms b3sum --num-threads 1
    70 ms b3sum

That's where the big performance gain is when using Blake3 IMO (even though 2.5x faster than a fast sha256 even when single-threaded is already nice).

yup, for comparison, same file as above using all the threads (32) on my system, I get about 45ms with fully parallel permitted b3. It does run into diminishing returns fairly quickly though; unsurprisingly no improvements in perf using hyperthreading, but also improvements drop off pretty fast with more cores.

  b3sum --num-threads 16 /tmp/rand_1G ran
    1.01 ± 0.02 times faster than b3sum --num-threads 15 /tmp/rand_1G
    1.01 ± 0.02 times faster than b3sum --num-threads 14 /tmp/rand_1G
    1.03 ± 0.02 times faster than b3sum --num-threads 13 /tmp/rand_1G
    1.04 ± 0.02 times faster than b3sum --num-threads 12 /tmp/rand_1G
    1.07 ± 0.02 times faster than b3sum --num-threads 11 /tmp/rand_1G
    1.10 ± 0.02 times faster than b3sum --num-threads 10 /tmp/rand_1G
    1.13 ± 0.02 times faster than b3sum --num-threads 9 /tmp/rand_1G
    1.20 ± 0.03 times faster than b3sum --num-threads 8 /tmp/rand_1G
    1.27 ± 0.03 times faster than b3sum --num-threads 7 /tmp/rand_1G
    1.37 ± 0.02 times faster than b3sum --num-threads 6 /tmp/rand_1G
    1.53 ± 0.05 times faster than b3sum --num-threads 5 /tmp/rand_1G
    1.72 ± 0.03 times faster than b3sum --num-threads 4 /tmp/rand_1G
    2.10 ± 0.04 times faster than b3sum --num-threads 3 /tmp/rand_1G
    2.84 ± 0.06 times faster than b3sum --num-threads 2 /tmp/rand_1G
    5.03 ± 0.12 times faster than b3sum --num-threads 1 /tmp/rand_1G

(over 16 elided from this run as they're all ~= the 16 time)

Figure 4 from https://github.com/BLAKE3-team/BLAKE3-specs/blob/master/blak... is a related benchmark. On that particular machine we saw good scaling up to 16 threads, but yeah somewhere in that neighborhood you start to run into memory bandwidth issues. Which is the problem you want I guess :)

Interestingly, sha256sum and openssl don't use sha_ni.

iced-cpuid $(which b3sum) AVX AVX2 AVX512F AVX512VL BMI1 CET_IBT CMOV SSE SSE2 SSE4_1 SSSE3 SYSCALL XSAVE

iced-cpuid $(which openssl ) CET_IBT CMOV SSE SSE2

iced-cpuid $(which sha256sum) CET_IBT CMOV SSE SSE2

Also, sha256sum in my case is a bit faster

Benchmark 1: openssl sha256 /tmp/rand_1G Time (mean ± σ): 540.0 ms ± 1.1 ms [User: 406.2 ms, System: 132.0 ms] Range (min … max): 538.5 ms … 542.3 ms 10 runs

Benchmark 2: b3sum --num-threads 1 /tmp/rand_1G Time (mean ± σ): 279.6 ms ± 0.8 ms [User: 213.9 ms, System: 64.4 ms] Range (min … max): 278.6 ms … 281.1 ms 10 runs

Benchmark 3: sha256sum /tmp/rand_1G Time (mean ± σ): 509.0 ms ± 6.3 ms [User: 386.4 ms, System: 120.5 ms] Range (min … max): 504.6 ms … 524.2 ms 10 runs

not sure that tool is correct; on my openssl it shows same output as you have there, but not aes-ni which is definitely enabled and functional.

ETA: ahh you want to do that on libcrypto:

  iced-cpuid <...>/libcrypto.so.3:
    ADX AES AVX AVX2 AVX512BW AVX512DQ AVX512F AVX512VL AVX512_IFMA BMI1 BMI2 CET_IBT CLFSH CMOV D3NOW MMX MOVBE MSR PCLMULQDQ PREFETCHW RDRAND RDSEED RTM SHA SMM SSE SSE2 SSE3 SSE4_1 SSSE3 SYSCALL TSC VMX XOP XSAVE

further research suggests that GNU coreutils cksum will use libcrypto in some configurations (though not mine); I expect that both both your commands above are actually using sha-ni

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