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glibc/sysdeps/aarch64/multiarch/memset_kunpeng.S

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aarch64: Optimized memset for Kunpeng processor. Due to the branch prediction issue of Kunpeng processor, we found memset_generic has poor performance on middle sizes setting, and so we reconstructed the logic, expanded the loop by 4 times in set_long to solve the problem, even when setting below 1K sizes have benefit. Another change is that DZ_ZVA seems no work when setting zero, so we discarded it and used set_long to set zero instead. Fewer branches and predictions also make the zero case have slightly improvement. Checked on aarch64-linux-gnu. Reviewed-by: Wilco Dijkstra <Wilco.Dijkstra@arm.com>
2019-12-19 15:26:33 +00:00
/* Optimized memset for Huawei Kunpeng processor.
Update copyright dates with scripts/update-copyrights I used these shell commands: ../glibc/scripts/update-copyrights $PWD/../gnulib/build-aux/update-copyright (cd ../glibc && git commit -am"[this commit message]") and then ignored the output, which consisted lines saying "FOO: warning: copyright statement not found" for each of 7061 files FOO. I then removed trailing white space from math/tgmath.h, support/tst-support-open-dev-null-range.c, and sysdeps/x86_64/multiarch/strlen-vec.S, to work around the following obscure pre-commit check failure diagnostics from Savannah. I don't know why I run into these diagnostics whereas others evidently do not. remote: *** 912-#endif remote: *** 913: remote: *** 914- remote: *** error: lines with trailing whitespace found ... remote: *** error: sysdeps/unix/sysv/linux/statx_cp.c: trailing lines
2022-01-01 18:54:23 +00:00
Copyright (C) 2012-2022 Free Software Foundation, Inc.
aarch64: Optimized memset for Kunpeng processor. Due to the branch prediction issue of Kunpeng processor, we found memset_generic has poor performance on middle sizes setting, and so we reconstructed the logic, expanded the loop by 4 times in set_long to solve the problem, even when setting below 1K sizes have benefit. Another change is that DZ_ZVA seems no work when setting zero, so we discarded it and used set_long to set zero instead. Fewer branches and predictions also make the zero case have slightly improvement. Checked on aarch64-linux-gnu. Reviewed-by: Wilco Dijkstra <Wilco.Dijkstra@arm.com>
2019-12-19 15:26:33 +00:00
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library. If not, see
<https://www.gnu.org/licenses/>. */
#include <sysdep.h>
#include <sysdeps/aarch64/memset-reg.h>
#if IS_IN (libc)
# define MEMSET __memset_kunpeng
/* Assumptions:
*
* ARMv8-a, AArch64, unaligned accesses
*
*/
ENTRY_ALIGN (MEMSET, 6)
aarch64: use PTR_ARG and SIZE_ARG instead of DELOUSE DELOUSE was added to asm code to make them compatible with non-LP64 ABIs, but it is an unfortunate name and the code was not compatible with ABIs where pointer and size_t are different. Glibc currently only supports the LP64 ABI so these macros are not really needed or tested, but for now the name is changed to be more meaningful instead of removing them completely. Some DELOUSE macros were dropped: clone, strlen and strnlen used it unnecessarily. The out of tree ILP32 patches are currently not maintained and will likely need a rework to rebase them on top of the time64 changes.
2020-12-17 10:03:05 +00:00
PTR_ARG (0)
SIZE_ARG (2)
aarch64: Optimized memset for Kunpeng processor. Due to the branch prediction issue of Kunpeng processor, we found memset_generic has poor performance on middle sizes setting, and so we reconstructed the logic, expanded the loop by 4 times in set_long to solve the problem, even when setting below 1K sizes have benefit. Another change is that DZ_ZVA seems no work when setting zero, so we discarded it and used set_long to set zero instead. Fewer branches and predictions also make the zero case have slightly improvement. Checked on aarch64-linux-gnu. Reviewed-by: Wilco Dijkstra <Wilco.Dijkstra@arm.com>
2019-12-19 15:26:33 +00:00
dup v0.16B, valw
add dstend, dstin, count
cmp count, 128
b.hs L(set_long)
cmp count, 16
b.lo L(less16)
/* Set 16..127 bytes. */
str q0, [dstin]
tbnz count, 6, L(set127)
str q0, [dstend, -16]
tbz count, 5, 1f
str q0, [dstin, 16]
str q0, [dstend, -32]
1: ret
.p2align 4
/* Set 64..127 bytes. Write 64 bytes from the start and
64 bytes from the end. */
L(set127):
stp q0, q0, [dstin, 16]
str q0, [dstin, 48]
stp q0, q0, [dstend, -64]
stp q0, q0, [dstend, -32]
ret
.p2align 4
/* Set 0..15 bytes. */
L(less16):
tbz count, 3, L(less8)
str d0, [dstin]
str d0, [dstend, -8]
ret
L(less8):
tbz count, 2, 2f
str s0, [dstin]
str s0, [dstend, -4]
ret
2: cbz count, 3f
str b0, [dstin]
tbz count, 1, 3f
str h0, [dstend, -2]
3: ret
.p2align 4
L(set_long):
bic dst, dstin, 15
str q0, [dstin]
sub count, dstend, dst /* Count is 16 too large. */
sub dst, dst, 16 /* Dst is biased by -32. */
sub count, count, 64 + 16 + 1 /* Adjust count and bias for loop. */
1: stp q0, q0, [dst, 32]
stp q0, q0, [dst, 64]!
subs count, count, 64
b.lo 1f
stp q0, q0, [dst, 32]
stp q0, q0, [dst, 64]!
subs count, count, 64
b.lo 1f
stp q0, q0, [dst, 32]
stp q0, q0, [dst, 64]!
subs count, count, 64
b.lo 1f
stp q0, q0, [dst, 32]
stp q0, q0, [dst, 64]!
subs count, count, 64
b.hs 1b
1: stp q0, q0, [dstend, -64]
stp q0, q0, [dstend, -32]
ret
END (MEMSET)
libc_hidden_builtin_def (MEMSET)
#endif
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