4 Commits
| Author | SHA1 | Message | Date |
|---|---|---|---|
Siddhesh Poyarekar
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2d9f35c2cc |
memcmp.S: optimize for medium to large sizes
This improved memcmp provides a fast path for compares up to 16 bytes and then compares 16 bytes at a time, thus optimizing loads from both sources. The glibc memcmp microbenchmark retains performance (with an error of ~1ns) for smaller compare sizes and reduces up to 31% of execution time for compares up to 4K on the APM Mustang. On Qualcomm Falkor this improves to almost 48%, i.e. it is almost 2x improvement for sizes of 2K and above. |
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Wilco Dijkstra
|
c86063bdc0 |
Optimized memcmp
This is an optimized memcmp for AArch64. This is a complete rewrite
using a different algorithm. The previous version split into cases
where both inputs were aligned, the inputs were mutually aligned and
unaligned using a byte loop. The new version combines all these cases,
while small inputs of less than 8 bytes are handled separately.
This allows the main code to be sped up using unaligned loads since
there are now at least 8 bytes to be compared. After the first 8 bytes,
align the first input. This ensures each iteration does at most one
unaligned access and mutually aligned inputs behave as aligned.
After the main loop, process the last 8 bytes using unaligned accesses.
This improves performance of (mutually) aligned cases by 25% and
unaligned by >500% (yes >6 times faster) on large inputs.
ChangeLog:
2017-06-28 Wilco Dijkstra <wdijkstr@arm.com>
* newlib/libc/machine/aarch64/memcmp.S (memcmp):
Rewrite of optimized memcmp.
GLIBC benchtests/bench-memcmp.c performance comparison for Cortex-A53:
Length 1, alignment 1/ 1: 153%
Length 1, alignment 1/ 1: 119%
Length 1, alignment 1/ 1: 154%
Length 2, alignment 2/ 2: 121%
Length 2, alignment 2/ 2: 140%
Length 2, alignment 2/ 2: 121%
Length 3, alignment 3/ 3: 105%
Length 3, alignment 3/ 3: 105%
Length 3, alignment 3/ 3: 105%
Length 4, alignment 4/ 4: 155%
Length 4, alignment 4/ 4: 154%
Length 4, alignment 4/ 4: 161%
Length 5, alignment 5/ 5: 173%
Length 5, alignment 5/ 5: 173%
Length 5, alignment 5/ 5: 173%
Length 6, alignment 6/ 6: 145%
Length 6, alignment 6/ 6: 145%
Length 6, alignment 6/ 6: 145%
Length 7, alignment 7/ 7: 125%
Length 7, alignment 7/ 7: 125%
Length 7, alignment 7/ 7: 125%
Length 8, alignment 8/ 8: 111%
Length 8, alignment 8/ 8: 130%
Length 8, alignment 8/ 8: 124%
Length 9, alignment 9/ 9: 160%
Length 9, alignment 9/ 9: 160%
Length 9, alignment 9/ 9: 150%
Length 10, alignment 10/10: 170%
Length 10, alignment 10/10: 137%
Length 10, alignment 10/10: 150%
Length 11, alignment 11/11: 160%
Length 11, alignment 11/11: 160%
Length 11, alignment 11/11: 160%
Length 12, alignment 12/12: 146%
Length 12, alignment 12/12: 168%
Length 12, alignment 12/12: 156%
Length 13, alignment 13/13: 167%
Length 13, alignment 13/13: 167%
Length 13, alignment 13/13: 173%
Length 14, alignment 14/14: 167%
Length 14, alignment 14/14: 168%
Length 14, alignment 14/14: 168%
Length 15, alignment 15/15: 168%
Length 15, alignment 15/15: 173%
Length 15, alignment 15/15: 173%
Length 1, alignment 0/ 0: 134%
Length 1, alignment 0/ 0: 127%
Length 1, alignment 0/ 0: 119%
Length 2, alignment 0/ 0: 94%
Length 2, alignment 0/ 0: 94%
Length 2, alignment 0/ 0: 106%
Length 3, alignment 0/ 0: 82%
Length 3, alignment 0/ 0: 87%
Length 3, alignment 0/ 0: 82%
Length 4, alignment 0/ 0: 115%
Length 4, alignment 0/ 0: 115%
Length 4, alignment 0/ 0: 122%
Length 5, alignment 0/ 0: 127%
Length 5, alignment 0/ 0: 119%
Length 5, alignment 0/ 0: 127%
Length 6, alignment 0/ 0: 103%
Length 6, alignment 0/ 0: 100%
Length 6, alignment 0/ 0: 100%
Length 7, alignment 0/ 0: 82%
Length 7, alignment 0/ 0: 91%
Length 7, alignment 0/ 0: 87%
Length 8, alignment 0/ 0: 111%
Length 8, alignment 0/ 0: 124%
Length 8, alignment 0/ 0: 124%
Length 9, alignment 0/ 0: 136%
Length 9, alignment 0/ 0: 136%
Length 9, alignment 0/ 0: 136%
Length 10, alignment 0/ 0: 136%
Length 10, alignment 0/ 0: 135%
Length 10, alignment 0/ 0: 136%
Length 11, alignment 0/ 0: 136%
Length 11, alignment 0/ 0: 136%
Length 11, alignment 0/ 0: 135%
Length 12, alignment 0/ 0: 136%
Length 12, alignment 0/ 0: 136%
Length 12, alignment 0/ 0: 136%
Length 13, alignment 0/ 0: 135%
Length 13, alignment 0/ 0: 136%
Length 13, alignment 0/ 0: 136%
Length 14, alignment 0/ 0: 136%
Length 14, alignment 0/ 0: 136%
Length 14, alignment 0/ 0: 136%
Length 15, alignment 0/ 0: 136%
Length 15, alignment 0/ 0: 136%
Length 15, alignment 0/ 0: 136%
Length 4, alignment 0/ 0: 115%
Length 4, alignment 0/ 0: 115%
Length 4, alignment 0/ 0: 115%
Length 32, alignment 0/ 0: 127%
Length 32, alignment 7/ 2: 395%
Length 32, alignment 0/ 0: 127%
Length 32, alignment 0/ 0: 127%
Length 8, alignment 0/ 0: 111%
Length 8, alignment 0/ 0: 124%
Length 8, alignment 0/ 0: 124%
Length 64, alignment 0/ 0: 128%
Length 64, alignment 6/ 4: 475%
Length 64, alignment 0/ 0: 131%
Length 64, alignment 0/ 0: 134%
Length 16, alignment 0/ 0: 128%
Length 16, alignment 0/ 0: 119%
Length 16, alignment 0/ 0: 128%
Length 128, alignment 0/ 0: 129%
Length 128, alignment 5/ 6: 475%
Length 128, alignment 0/ 0: 130%
Length 128, alignment 0/ 0: 129%
Length 32, alignment 0/ 0: 126%
Length 32, alignment 0/ 0: 126%
Length 32, alignment 0/ 0: 126%
Length 256, alignment 0/ 0: 127%
Length 256, alignment 4/ 8: 545%
Length 256, alignment 0/ 0: 126%
Length 256, alignment 0/ 0: 128%
Length 64, alignment 0/ 0: 171%
Length 64, alignment 0/ 0: 171%
Length 64, alignment 0/ 0: 174%
Length 512, alignment 0/ 0: 126%
Length 512, alignment 3/10: 585%
Length 512, alignment 0/ 0: 126%
Length 512, alignment 0/ 0: 127%
Length 128, alignment 0/ 0: 129%
Length 128, alignment 0/ 0: 128%
Length 128, alignment 0/ 0: 129%
Length 1024, alignment 0/ 0: 125%
Length 1024, alignment 2/12: 611%
Length 1024, alignment 0/ 0: 126%
Length 1024, alignment 0/ 0: 126%
Length 256, alignment 0/ 0: 128%
Length 256, alignment 0/ 0: 127%
Length 256, alignment 0/ 0: 128%
Length 2048, alignment 0/ 0: 125%
Length 2048, alignment 1/14: 625%
Length 2048, alignment 0/ 0: 125%
Length 2048, alignment 0/ 0: 125%
Length 512, alignment 0/ 0: 126%
Length 512, alignment 0/ 0: 127%
Length 512, alignment 0/ 0: 127%
Length 4096, alignment 0/ 0: 125%
Length 4096, alignment 0/16: 125%
Length 4096, alignment 0/ 0: 125%
Length 4096, alignment 0/ 0: 125%
Length 1024, alignment 0/ 0: 126%
Length 1024, alignment 0/ 0: 126%
Length 1024, alignment 0/ 0: 126%
Length 8192, alignment 0/ 0: 125%
Length 8192, alignment 63/18: 636%
Length 8192, alignment 0/ 0: 125%
Length 8192, alignment 0/ 0: 125%
Length 16, alignment 1/ 2: 317%
Length 16, alignment 1/ 2: 317%
Length 16, alignment 1/ 2: 317%
Length 32, alignment 2/ 4: 395%
Length 32, alignment 2/ 4: 395%
Length 32, alignment 2/ 4: 398%
Length 64, alignment 3/ 6: 475%
Length 64, alignment 3/ 6: 475%
Length 64, alignment 3/ 6: 477%
Length 128, alignment 4/ 8: 479%
Length 128, alignment 4/ 8: 479%
Length 128, alignment 4/ 8: 479%
Length 256, alignment 5/10: 543%
Length 256, alignment 5/10: 539%
Length 256, alignment 5/10: 543%
Length 512, alignment 6/12: 585%
Length 512, alignment 6/12: 585%
Length 512, alignment 6/12: 585%
Length 1024, alignment 7/14: 611%
Length 1024, alignment 7/14: 611%
Length 1024, alignment 7/14: 611%
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Sebastian Pop
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9938a64ca9 |
aarch64: optimize the unaligned case of memcmp
This brings to newlib a performance improvement that we developed in Bionic libc. That change has been submitted for review to Bionic libc: https://android-review.googlesource.com/418279 A similar patch has been submitted for review in glibc: https://sourceware.org/ml/libc-alpha/2017-06/msg01143.html Patch written by Vikas Sinha and Sebastian Pop. The performance was measured on the bionic-benchmarks on a hikey (aarch64 8xA53) board. There was no performance change to the existing benchmark and a performance improvement on the new benchmark for memcmp on the unaligned side. The new benchmark has been submitted for review at https://android-review.googlesource.com/414860 The overall performance improves by 18% for the small data set 8 and the performance improves by 450% for the large data set 64k. The base is with the libc from /system/lib64. The bionic libc with this patch is in /data. hikey:/data # export LD_LIBRARY_PATH=/system/lib64 hikey:/data # ./bionic-benchmarks --benchmark_filter='BM_string_memcmp*' Run on (8 X 2.4 MHz CPU s) Benchmark Time CPU Iterations ---------------------------------------------------------------------- BM_string_memcmp/8 30 ns 30 ns 22955680 251.07MB/s BM_string_memcmp/64 57 ns 57 ns 12349184 1076.99MB/s BM_string_memcmp/512 305 ns 305 ns 2297163 1.56496GB/s BM_string_memcmp/1024 571 ns 571 ns 1225211 1.66912GB/s BM_string_memcmp/8k 4307 ns 4306 ns 162562 1.77177GB/s BM_string_memcmp/16k 8676 ns 8675 ns 80676 1.75887GB/s BM_string_memcmp/32k 19233 ns 19230 ns 36394 1.58695GB/s BM_string_memcmp/64k 36986 ns 36984 ns 18952 1.65029GB/s BM_string_memcmp_aligned/8 199 ns 199 ns 3519166 38.3336MB/s BM_string_memcmp_aligned/64 386 ns 386 ns 1810734 158.073MB/s BM_string_memcmp_aligned/512 1735 ns 1734 ns 403981 281.525MB/s BM_string_memcmp_aligned/1024 3200 ns 3200 ns 218838 305.151MB/s BM_string_memcmp_aligned/8k 25084 ns 25080 ns 28180 311.507MB/s BM_string_memcmp_aligned/16k 51730 ns 51729 ns 13521 302.057MB/s BM_string_memcmp_aligned/32k 103228 ns 103228 ns 6782 302.727MB/s BM_string_memcmp_aligned/64k 207117 ns 207087 ns 3450 301.806MB/s BM_string_memcmp_unaligned/8 339 ns 339 ns 2070998 22.5302MB/s BM_string_memcmp_unaligned/64 1392 ns 1392 ns 502796 43.8454MB/s BM_string_memcmp_unaligned/512 9194 ns 9194 ns 76133 53.1104MB/s BM_string_memcmp_unaligned/1024 18325 ns 18323 ns 38206 53.2963MB/s BM_string_memcmp_unaligned/8k 148579 ns 148574 ns 4713 52.5831MB/s BM_string_memcmp_unaligned/16k 298169 ns 298120 ns 2344 52.4118MB/s BM_string_memcmp_unaligned/32k 598813 ns 598797 ns 1085 52.188MB/s BM_string_memcmp_unaligned/64k 1196079 ns 1196083 ns 540 52.2539MB/s hikey:/data # export LD_LIBRARY_PATH=/data hikey:/data # ./bionic-benchmarks --benchmark_filter='BM_string_memcmp*' Run on (8 X 2.4 MHz CPU s) Benchmark Time CPU Iterations ---------------------------------------------------------------------- BM_string_memcmp/8 30 ns 30 ns 23209918 252.802MB/s BM_string_memcmp/64 57 ns 57 ns 12348447 1076.95MB/s BM_string_memcmp/512 305 ns 305 ns 2296878 1.56471GB/s BM_string_memcmp/1024 572 ns 571 ns 1224426 1.6689GB/s BM_string_memcmp/8k 4309 ns 4308 ns 162491 1.77109GB/s BM_string_memcmp/16k 9348 ns 9345 ns 74894 1.63285GB/s BM_string_memcmp/32k 18329 ns 18322 ns 38249 1.6656GB/s BM_string_memcmp/64k 36992 ns 36981 ns 18952 1.65045GB/s BM_string_memcmp_aligned/8 199 ns 199 ns 3513925 38.3162MB/s BM_string_memcmp_aligned/64 386 ns 386 ns 1814038 158.192MB/s BM_string_memcmp_aligned/512 1735 ns 1735 ns 402279 281.502MB/s BM_string_memcmp_aligned/1024 3204 ns 3202 ns 218761 304.941MB/s BM_string_memcmp_aligned/8k 25577 ns 25569 ns 27406 305.548MB/s BM_string_memcmp_aligned/16k 52143 ns 52123 ns 13522 299.769MB/s BM_string_memcmp_aligned/32k 105169 ns 105127 ns 6637 297.26MB/s BM_string_memcmp_aligned/64k 206508 ns 206383 ns 3417 302.835MB/s BM_string_memcmp_unaligned/8 282 ns 282 ns 2482953 27.062MB/s BM_string_memcmp_unaligned/64 542 ns 541 ns 1298317 112.77MB/s BM_string_memcmp_unaligned/512 2152 ns 2152 ns 325267 226.915MB/s BM_string_memcmp_unaligned/1024 4025 ns 4025 ns 173904 242.622MB/s BM_string_memcmp_unaligned/8k 32276 ns 32271 ns 21818 242.09MB/s BM_string_memcmp_unaligned/16k 65970 ns 65970 ns 10554 236.851MB/s BM_string_memcmp_unaligned/32k 131241 ns 131242 ns 5129 238.11MB/s BM_string_memcmp_unaligned/64k 266159 ns 266160 ns 2661 234.821MB/s |
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Marcus Shawcroft
|
211f1ec717 |
2013-01-10 Marcus Shawcroft <marcus.shawcroft@linaro.org>
* libc/machine/aarch64/Makefile.am (lib_a_SOURCES): Add
memcmp-stub.c and memcmp.S
* libc/machine/aarch64/Makefile.in: Regenerated.
* libc/machine/aarch64/memcmp-stub.c: New file.
* libc/machine/aarch64/memcmp.S: New file.
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