diff mbox series

[2/2] riscv: Optimize memset

Message ID 20230510035243.8586-3-zhang_fei_0403@163.com (mailing list archive)
State Changes Requested, archived
Headers show
Series riscv: Optimize memset for data sizes less than 16 bytes | expand

Checks

Context Check Description
conchuod/source_inline success Was 0 now: 0
conchuod/cover_letter success Series has a cover letter
conchuod/tree_selection success Guessed tree name to be for-next at HEAD ac9a78681b92
conchuod/fixes_present success Fixes tag not required for -next series
conchuod/maintainers_pattern success MAINTAINERS pattern errors before the patch: 6 and now 6
conchuod/verify_signedoff success Signed-off-by tag matches author and committer
conchuod/kdoc success Errors and warnings before: 0 this patch: 0
conchuod/build_rv64_clang_allmodconfig success Errors and warnings before: 8 this patch: 8
conchuod/module_param success Was 0 now: 0
conchuod/build_rv64_gcc_allmodconfig success Errors and warnings before: 8 this patch: 8
conchuod/build_rv32_defconfig success Build OK
conchuod/dtb_warn_rv64 success Errors and warnings before: 3 this patch: 3
conchuod/header_inline success No static functions without inline keyword in header files
conchuod/checkpatch warning WARNING: From:/Signed-off-by: email name mismatch: 'From: zhangfei <zhangfei@nj.iscas.ac.cn>' != 'Signed-off-by: Fei Zhang <zhangfei@nj.iscas.ac.cn>'
conchuod/build_rv64_nommu_k210_defconfig success Build OK
conchuod/verify_fixes success No Fixes tag
conchuod/build_rv64_nommu_virt_defconfig success Build OK

Commit Message

zhangfei May 10, 2023, 3:52 a.m. UTC 
From: zhangfei <zhangfei@nj.iscas.ac.cn>

This patch has been optimized for memset data sizes less than 16 bytes.
Compared to byte by byte storage, significant performance improvement has been achieved.
It allows storage instructions to be executed in parallel and reduces the number of jumps.

Signed-off-by: Fei Zhang <zhangfei@nj.iscas.ac.cn>
---
 arch/riscv/lib/memset.S | 33 ++++++++++++++++++++++++++++++---
 1 file changed, 30 insertions(+), 3 deletions(-)
diff mbox series

Patch

diff --git a/arch/riscv/lib/memset.S b/arch/riscv/lib/memset.S
index e613c5c27998..6113a2696e79 100644
--- a/arch/riscv/lib/memset.S
+++ b/arch/riscv/lib/memset.S
@@ -106,9 +106,36 @@  WEAK(memset)
 	beqz	a2, 6f
 	add	a3, t0, a2
 5:
-	sb	a1, 0(t0)
-	addi	t0, t0, 1
-	bltu	t0, a3, 5b
+       sb      a1,  0(t0)
+       sb      a1, -1(a3)
+       li      a4, 2
+       bgeu    a4, a2, 6f
+
+       sb 	a1,  1(t0)
+       sb 	a1,  2(t0)
+       sb 	a1, -2(a3)
+       sb 	a1, -3(a3)
+       li 	a4, 6
+       bgeu 	a4, a2, 6f
+
+       sb 	a1,  3(t0)
+       sb 	a1, -4(a3)
+       li 	a4, 8
+       bgeu    a4, a2, 6f
+
+       sb 	a1,  4(t0)
+       sb 	a1, -5(a3)
+       li 	a4, 10
+       bgeu 	a4, a2, 6f
+
+       sb 	a1,  5(t0)
+       sb 	a1,  6(t0)
+       sb 	a1, -6(a3)
+       sb 	a1, -7(a3)
+       li 	a4, 14
+       bgeu 	a4, a2, 6f
+
+       sb 	a1, 7(t0)
 6:
 	ret
 END(__memset)