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aklomp / base64

Fast Base64 stream encoder/decoder in C99, with SIMD acceleration
BSD 2-Clause "Simplified" License
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Improve NEON64 decoding speed #25

Closed mayeut closed 7 years ago

mayeut commented 7 years ago

The decoding loop now uses a composite 128 bytes LUT (two 64 bytes LUT)

Speed-up on iPhone SE using Apple LLVM version 8.0.0 (clang-800.0.38)

NEON64: +130% compared to previous version

Full results before & after modifications follows. Before:

Filling buffer with 10.0 MB of random data...
Testing with buffer size 10 MB, fastest of 100 * 1
NEON64  encode  4098.43 MB/sec
NEON64  decode  1726.01 MB/sec
plain   encode  1060.69 MB/sec
plain   decode  1236.70 MB/sec
Testing with buffer size 1 MB, fastest of 100 * 10
NEON64  encode  6550.93 MB/sec
NEON64  decode  1744.40 MB/sec
plain   encode  1062.92 MB/sec
plain   decode  1235.20 MB/sec
Testing with buffer size 100 KB, fastest of 100 * 100
NEON64  encode  6537.48 MB/sec
NEON64  decode  1733.39 MB/sec
plain   encode  1063.61 MB/sec
plain   decode  1233.14 MB/sec
Testing with buffer size 10 KB, fastest of 1000 * 100
NEON64  encode  6499.58 MB/sec
NEON64  decode  1751.95 MB/sec
plain   encode  1080.12 MB/sec
plain   decode  1237.07 MB/sec
Testing with buffer size 1 KB, fastest of 1000 * 1000
NEON64  encode  5840.41 MB/sec
NEON64  decode  1700.96 MB/sec
plain   encode  1059.08 MB/sec
plain   decode  1206.38 MB/sec

After:

Filling buffer with 10.0 MB of random data...
Testing with buffer size 10 MB, fastest of 100 * 1
NEON64  encode  4102.50 MB/sec
NEON64  decode  3984.66 MB/sec
plain   encode  1061.91 MB/sec
plain   decode  1234.36 MB/sec
Testing with buffer size 1 MB, fastest of 10 * 100
NEON64  encode  6508.42 MB/sec
NEON64  decode  3984.97 MB/sec
plain   encode  1060.76 MB/sec
plain   decode  1231.69 MB/sec
Testing with buffer size 100 KB, fastest of 100 * 100
NEON64  encode  6534.92 MB/sec
NEON64  decode  3989.63 MB/sec
plain   encode  1062.90 MB/sec
plain   decode  1233.14 MB/sec
Testing with buffer size 10 KB, fastest of 1000 * 100
NEON64  encode  6476.27 MB/sec
NEON64  decode  3968.43 MB/sec
plain   encode  1082.06 MB/sec
plain   decode  1238.31 MB/sec
Testing with buffer size 1 KB, fastest of 1000 * 1000
NEON64  encode  5840.41 MB/sec
NEON64  decode  3923.26 MB/sec
plain   encode  1065.29 MB/sec
plain   decode  1220.13 MB/sec
aklomp commented 7 years ago

This is really clever, good work! I'll review it further tomorrow or in the weekend.

aklomp commented 7 years ago

Thanks, merged. I rebased the commit onto Master so that I could do a fast-forward merge.