[PATCH v2] aarch64: MTE compatible strchrnul
Andrea Corallo
andrea.corallo@arm.com
Fri Jun 5 15:18:49 GMT 2020
Hi all,
I'd like to submit this patch introducing an Arm MTE compatible
strchrnul implementation.
Follows a performance comparison (obtained using glibc benchtests) of the
strchrnul benchmark run on Cortex-A72, Cortex-A53, Neoverse N1.
| length | alignment | perf-uplift A72 | perf-uplift A53 | perf-uplift N1 |
|--------+-----------+-----------------+-----------------+----------------|
| 32 | 0 | 1.16x | 1.07x | 1.35x |
| 32 | 1 | 1.25x | 1.16x | 1.15x |
| 64 | 0 | 1.26x | 0.97x | 1.20x |
| 64 | 2 | 1.35x | 1.04x | 1.30x |
| 128 | 0 | 1.12x | 0.84x | 1.22x |
| 128 | 3 | 1.25x | 0.87x | 1.30x |
| 256 | 0 | 1.14x | 0.84x | 1.16x |
| 256 | 4 | 1.24x | 0.81x | 1.16x |
| 512 | 0 | 1.15x | 0.80x | 1.13x |
| 512 | 5 | 1.17x | 0.81x | 1.14x |
| 1024 | 0 | 1.14x | 0.78x | 1.08x |
| 1024 | 6 | 1.03x | 0.78x | 1.10x |
| 2048 | 0 | 1.12x | 0.76x | 1.08x |
| 2048 | 7 | 1.14x | 0.77x | 1.09x |
| 64 | 1 | 1.35x | 1.04x | 1.37x |
| 64 | 1 | 1.36x | 1.04x | 1.37x |
| 64 | 2 | 1.36x | 1.04x | 1.37x |
| 64 | 2 | 1.37x | 1.04x | 1.38x |
| 64 | 3 | 1.38x | 1.04x | 1.36x |
| 64 | 3 | 1.40x | 1.04x | 1.36x |
| 64 | 4 | 1.41x | 1.04x | 1.36x |
| 64 | 4 | 1.36x | 1.04x | 1.36x |
| 64 | 5 | 1.34x | 1.04x | 1.40x |
| 64 | 5 | 1.35x | 1.04x | 1.36x |
| 64 | 6 | 1.34x | 1.04x | 1.37x |
| 64 | 6 | 1.41x | 1.04x | 1.37x |
| 64 | 7 | 1.39x | 1.04x | 1.36x |
| 64 | 7 | 1.34x | 1.04x | 1.37x |
| 0 | 0 | 1.18x | 1.63x | 1.66x |
| 0 | 0 | 1.18x | 1.63x | 1.66x |
| 1 | 0 | 1.18x | 1.63x | 1.66x |
| 1 | 0 | 1.18x | 1.63x | 1.67x |
| 2 | 0 | 1.18x | 1.63x | 1.66x |
| 2 | 0 | 1.18x | 1.63x | 1.65x |
| 3 | 0 | 1.18x | 1.63x | 1.66x |
| 3 | 0 | 1.18x | 1.63x | 1.66x |
| 4 | 0 | 1.18x | 1.63x | 1.65x |
| 4 | 0 | 1.18x | 1.63x | 1.66x |
| 5 | 0 | 1.18x | 1.63x | 1.66x |
| 5 | 0 | 1.18x | 1.63x | 1.66x |
| 6 | 0 | 1.18x | 1.63x | 1.66x |
| 6 | 0 | 1.18x | 1.63x | 1.66x |
| 7 | 0 | 1.18x | 1.63x | 1.66x |
| 7 | 0 | 1.18x | 1.63x | 1.64x |
| 8 | 0 | 1.18x | 1.63x | 1.66x |
| 8 | 0 | 1.18x | 1.63x | 1.66x |
| 9 | 0 | 1.18x | 1.63x | 1.65x |
| 9 | 0 | 1.18x | 1.63x | 1.66x |
| 10 | 0 | 1.18x | 1.63x | 1.66x |
| 10 | 0 | 1.18x | 1.63x | 1.66x |
| 11 | 0 | 1.18x | 1.63x | 1.64x |
| 11 | 0 | 1.18x | 1.63x | 1.63x |
| 12 | 0 | 1.18x | 1.63x | 1.63x |
| 12 | 0 | 1.18x | 1.63x | 1.66x |
| 13 | 0 | 1.18x | 1.63x | 1.63x |
| 13 | 0 | 1.18x | 1.63x | 1.63x |
| 14 | 0 | 1.18x | 1.63x | 1.63x |
| 14 | 0 | 1.18x | 1.63x | 1.22x |
| 15 | 0 | 1.19x | 1.63x | 1.22x |
| 15 | 0 | 1.18x | 1.63x | 1.63x |
| 16 | 0 | 1.03x | 0.96x | 1.15x |
| 16 | 0 | 1.03x | 0.96x | 1.13x |
| 17 | 0 | 1.03x | 0.96x | 0.98x |
| 17 | 0 | 1.03x | 0.96x | 0.98x |
| 18 | 0 | 1.03x | 0.96x | 0.98x |
| 18 | 0 | 1.03x | 0.96x | 0.98x |
| 19 | 0 | 1.04x | 0.96x | 0.98x |
| 19 | 0 | 1.04x | 0.96x | 0.98x |
| 20 | 0 | 1.04x | 0.96x | 1.00x |
| 20 | 0 | 1.03x | 0.96x | 0.99x |
| 21 | 0 | 1.04x | 0.96x | 0.99x |
| 21 | 0 | 1.03x | 0.96x | 1.14x |
| 22 | 0 | 1.04x | 0.96x | 1.14x |
| 22 | 0 | 1.03x | 0.96x | 1.14x |
| 23 | 0 | 1.03x | 0.96x | 1.13x |
| 23 | 0 | 1.03x | 0.96x | 1.15x |
| 24 | 0 | 1.04x | 0.96x | 1.13x |
| 24 | 0 | 1.04x | 0.95x | 1.13x |
| 25 | 0 | 1.03x | 0.96x | 1.15x |
| 25 | 0 | 1.04x | 0.96x | 1.12x |
| 26 | 0 | 1.04x | 0.96x | 1.13x |
| 26 | 0 | 1.02x | 0.96x | 1.13x |
| 27 | 0 | 1.04x | 0.96x | 1.13x |
| 27 | 0 | 1.03x | 0.96x | 1.13x |
| 28 | 0 | 1.03x | 0.96x | 0.98x |
| 28 | 0 | 1.04x | 0.96x | 1.05x |
| 29 | 0 | 1.02x | 0.96x | 1.00x |
| 29 | 0 | 1.03x | 0.96x | 1.00x |
| 30 | 0 | 1.04x | 0.96x | 1.00x |
| 30 | 0 | 1.04x | 0.96x | 1.00x |
| 31 | 0 | 1.04x | 0.96x | 0.99x |
| 31 | 0 | 1.03x | 0.96x | 0.99x |
| 32 | 0 | 1.09x | 1.07x | 1.09x |
| 32 | 1 | 1.25x | 1.15x | 1.38x |
| 64 | 0 | 1.27x | 0.98x | 1.20x |
| 64 | 2 | 1.41x | 1.04x | 1.30x |
| 128 | 0 | 1.15x | 0.84x | 1.22x |
| 128 | 3 | 1.23x | 0.87x | 1.30x |
| 256 | 0 | 1.16x | 0.84x | 1.16x |
| 256 | 4 | 1.23x | 0.81x | 1.17x |
| 512 | 0 | 1.14x | 0.80x | 1.12x |
| 512 | 5 | 1.18x | 0.81x | 1.14x |
| 1024 | 0 | 1.16x | 0.78x | 1.09x |
| 1024 | 6 | 1.03x | 0.78x | 1.11x |
| 2048 | 0 | 1.14x | 0.76x | 1.08x |
| 2048 | 7 | 1.14x | 0.77x | 1.09x |
| 64 | 1 | 1.40x | 1.04x | 1.37x |
| 64 | 1 | 1.40x | 1.04x | 1.37x |
| 64 | 2 | 1.35x | 1.04x | 1.37x |
| 64 | 2 | 1.38x | 1.04x | 1.37x |
| 64 | 3 | 1.36x | 1.04x | 1.37x |
| 64 | 3 | 1.34x | 1.04x | 1.37x |
| 64 | 4 | 1.41x | 1.04x | 1.37x |
| 64 | 4 | 1.38x | 1.04x | 1.37x |
| 64 | 5 | 1.36x | 1.04x | 1.37x |
| 64 | 5 | 1.36x | 1.04x | 1.37x |
| 64 | 6 | 1.35x | 1.04x | 1.37x |
| 64 | 6 | 1.40x | 1.04x | 1.37x |
| 64 | 7 | 1.35x | 1.04x | 1.37x |
| 64 | 7 | 1.40x | 1.04x | 1.37x |
| 0 | 0 | 1.19x | 1.63x | 1.66x |
| 0 | 0 | 1.19x | 1.63x | 1.66x |
| 1 | 0 | 1.19x | 1.63x | 1.66x |
| 1 | 0 | 1.19x | 1.63x | 1.66x |
| 2 | 0 | 1.18x | 1.63x | 1.63x |
| 2 | 0 | 1.18x | 1.63x | 1.66x |
| 3 | 0 | 1.18x | 1.63x | 1.66x |
| 3 | 0 | 1.20x | 1.63x | 1.63x |
| 4 | 0 | 1.18x | 1.63x | 1.63x |
| 4 | 0 | 1.18x | 1.63x | 1.66x |
| 5 | 0 | 1.18x | 1.63x | 1.66x |
| 5 | 0 | 1.18x | 1.63x | 1.66x |
| 6 | 0 | 1.18x | 1.63x | 1.66x |
| 6 | 0 | 1.18x | 1.63x | 1.66x |
| 7 | 0 | 1.18x | 1.63x | 1.66x |
| 7 | 0 | 1.18x | 1.63x | 1.66x |
| 8 | 0 | 1.18x | 1.63x | 1.25x |
| 8 | 0 | 1.18x | 1.63x | 1.66x |
| 9 | 0 | 1.18x | 1.63x | 1.66x |
| 9 | 0 | 1.18x | 1.63x | 1.66x |
| 10 | 0 | 1.18x | 1.63x | 1.66x |
| 10 | 0 | 1.18x | 1.63x | 1.66x |
| 11 | 0 | 1.18x | 1.63x | 1.66x |
| 11 | 0 | 1.18x | 1.63x | 1.66x |
| 12 | 0 | 1.18x | 1.63x | 1.66x |
| 12 | 0 | 1.19x | 1.63x | 1.66x |
| 13 | 0 | 1.18x | 1.63x | 1.66x |
| 13 | 0 | 1.18x | 1.63x | 1.66x |
| 14 | 0 | 1.19x | 1.63x | 1.66x |
| 14 | 0 | 1.19x | 1.63x | 1.66x |
| 15 | 0 | 1.18x | 1.63x | 1.66x |
| 15 | 0 | 1.18x | 1.63x | 1.66x |
| 16 | 0 | 1.03x | 0.96x | 1.00x |
| 16 | 0 | 1.03x | 0.96x | 1.00x |
| 17 | 0 | 1.03x | 0.96x | 1.00x |
| 17 | 0 | 1.03x | 0.96x | 1.15x |
| 18 | 0 | 1.03x | 0.96x | 1.14x |
| 18 | 0 | 1.04x | 0.96x | 1.15x |
| 19 | 0 | 1.04x | 0.96x | 1.15x |
| 19 | 0 | 1.04x | 0.96x | 1.15x |
| 20 | 0 | 1.04x | 0.96x | 1.15x |
| 20 | 0 | 1.03x | 0.96x | 1.15x |
| 21 | 0 | 1.04x | 0.96x | 1.15x |
| 21 | 0 | 1.03x | 0.96x | 1.15x |
| 22 | 0 | 1.02x | 0.96x | 1.15x |
| 22 | 0 | 1.03x | 0.96x | 1.15x |
| 23 | 0 | 1.03x | 0.96x | 1.15x |
| 23 | 0 | 1.03x | 0.96x | 1.15x |
| 24 | 0 | 1.03x | 0.96x | 1.00x |
| 24 | 0 | 1.02x | 0.96x | 1.00x |
| 25 | 0 | 1.04x | 0.96x | 1.00x |
| 25 | 0 | 1.03x | 0.96x | 1.16x |
| 26 | 0 | 1.04x | 0.96x | 1.15x |
| 26 | 0 | 1.03x | 0.96x | 1.15x |
| 27 | 0 | 1.04x | 0.96x | 1.00x |
| 27 | 0 | 1.03x | 0.96x | 1.00x |
| 28 | 0 | 1.04x | 0.96x | 1.00x |
| 28 | 0 | 1.04x | 0.96x | 1.00x |
| 29 | 0 | 1.03x | 0.96x | 1.00x |
| 29 | 0 | 1.04x | 0.96x | 1.15x |
| 30 | 0 | 1.04x | 0.96x | 1.15x |
| 30 | 0 | 1.03x | 0.95x | 1.00x |
| 31 | 0 | 1.03x | 0.96x | 1.00x |
| 31 | 0 | 1.04x | 0.96x | 1.00x |
This patch is passing GLIBC tests.
Regards
Andrea
8< --- 8< --- 8<
Introduce an Arm MTE compatible strchrnul implementation.
The existing implementation assumes that any access to the pages in
which the string resides is safe. This assumption is not true when
MTE is enabled. This patch updates the algorithm to ensure that
accesses remain within the bounds of an MTE tag (16-byte chunks) and
improves overall performance.
Benchmarked on Cortex-A72, Cortex-A53, Neoverse N1.
Co-authored-by: Wilco Dijkstra <wilco.dijkstra@arm.com>
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