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author | Wilco Dijkstra <wdijkstr@arm.com> | 2021-08-10 13:30:27 +0100 |
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committer | Wilco Dijkstra <wdijkstr@arm.com> | 2021-08-10 13:30:27 +0100 |
commit | 07b427296b8d59f439144029d9a948f6c1ce0a31 (patch) | |
tree | a07eb48b7dbd93af15343faad65d41159ff835e1 /sysdeps | |
parent | 1d7b32ee6145c46c4f4f8a208a6b72e0668d7cf3 (diff) | |
download | glibc-07b427296b8d59f439144029d9a948f6c1ce0a31.zip glibc-07b427296b8d59f439144029d9a948f6c1ce0a31.tar.gz glibc-07b427296b8d59f439144029d9a948f6c1ce0a31.tar.bz2 |
[1/5] AArch64: Improve A64FX memset for small sizes
Improve performance of small memsets by reducing instruction counts and
improving code alignment. Bench-memset shows 35-45% performance gain for
small sizes.
Reviewed-by: Naohiro Tamura <naohirot@fujitsu.com>
Diffstat (limited to 'sysdeps')
-rw-r--r-- | sysdeps/aarch64/multiarch/memset_a64fx.S | 96 |
1 files changed, 36 insertions, 60 deletions
diff --git a/sysdeps/aarch64/multiarch/memset_a64fx.S b/sysdeps/aarch64/multiarch/memset_a64fx.S index ce54e54..cf3d402 100644 --- a/sysdeps/aarch64/multiarch/memset_a64fx.S +++ b/sysdeps/aarch64/multiarch/memset_a64fx.S @@ -51,78 +51,54 @@ .endm .macro st1b_unroll first=0, last=7 - st1b z0.b, p0, [dst, #\first, mul vl] + st1b z0.b, p0, [dst, \first, mul vl] .if \last-\first st1b_unroll "(\first+1)", \last .endif .endm - .macro shortcut_for_small_size exit - // if rest <= vector_length * 2 - whilelo p0.b, xzr, count - whilelo p1.b, vector_length, count - b.last 1f - st1b z0.b, p0, [dstin, #0, mul vl] - st1b z0.b, p1, [dstin, #1, mul vl] - ret -1: // if rest > vector_length * 8 - cmp count, vector_length, lsl 3 // vector_length * 8 - b.hi \exit - // if rest <= vector_length * 4 - lsl tmp1, vector_length, 1 // vector_length * 2 - whilelo p2.b, tmp1, count - incb tmp1 - whilelo p3.b, tmp1, count - b.last 1f - st1b z0.b, p0, [dstin, #0, mul vl] - st1b z0.b, p1, [dstin, #1, mul vl] - st1b z0.b, p2, [dstin, #2, mul vl] - st1b z0.b, p3, [dstin, #3, mul vl] - ret -1: // if rest <= vector_length * 8 - lsl tmp1, vector_length, 2 // vector_length * 4 - whilelo p4.b, tmp1, count - incb tmp1 - whilelo p5.b, tmp1, count - b.last 1f - st1b z0.b, p0, [dstin, #0, mul vl] - st1b z0.b, p1, [dstin, #1, mul vl] - st1b z0.b, p2, [dstin, #2, mul vl] - st1b z0.b, p3, [dstin, #3, mul vl] - st1b z0.b, p4, [dstin, #4, mul vl] - st1b z0.b, p5, [dstin, #5, mul vl] - ret -1: lsl tmp1, vector_length, 2 // vector_length * 4 - incb tmp1 // vector_length * 5 - incb tmp1 // vector_length * 6 - whilelo p6.b, tmp1, count - incb tmp1 - whilelo p7.b, tmp1, count - st1b z0.b, p0, [dstin, #0, mul vl] - st1b z0.b, p1, [dstin, #1, mul vl] - st1b z0.b, p2, [dstin, #2, mul vl] - st1b z0.b, p3, [dstin, #3, mul vl] - st1b z0.b, p4, [dstin, #4, mul vl] - st1b z0.b, p5, [dstin, #5, mul vl] - st1b z0.b, p6, [dstin, #6, mul vl] - st1b z0.b, p7, [dstin, #7, mul vl] - ret - .endm -ENTRY (MEMSET) +#undef BTI_C +#define BTI_C +ENTRY (MEMSET) PTR_ARG (0) SIZE_ARG (2) - cbnz count, 1f - ret -1: dup z0.b, valw cntb vector_length - // shortcut for less than vector_length * 8 - // gives a free ptrue to p0.b for n >= vector_length - shortcut_for_small_size L(vl_agnostic) - // end of shortcut + dup z0.b, valw + whilelo p0.b, vector_length, count + b.last 1f + whilelo p1.b, xzr, count + st1b z0.b, p1, [dstin, 0, mul vl] + st1b z0.b, p0, [dstin, 1, mul vl] + ret + + // count >= vector_length * 2 +1: cmp count, vector_length, lsl 2 + add dstend, dstin, count + b.hi 1f + st1b z0.b, p0, [dstin, 0, mul vl] + st1b z0.b, p0, [dstin, 1, mul vl] + st1b z0.b, p0, [dstend, -2, mul vl] + st1b z0.b, p0, [dstend, -1, mul vl] + ret + + // count > vector_length * 4 +1: lsl tmp1, vector_length, 3 + cmp count, tmp1 + b.hi L(vl_agnostic) + st1b z0.b, p0, [dstin, 0, mul vl] + st1b z0.b, p0, [dstin, 1, mul vl] + st1b z0.b, p0, [dstin, 2, mul vl] + st1b z0.b, p0, [dstin, 3, mul vl] + st1b z0.b, p0, [dstend, -4, mul vl] + st1b z0.b, p0, [dstend, -3, mul vl] + st1b z0.b, p0, [dstend, -2, mul vl] + st1b z0.b, p0, [dstend, -1, mul vl] + ret + .p2align 4 L(vl_agnostic): // VL Agnostic mov rest, count mov dst, dstin |