When copy over 128 bytes, src/dst is added after
each ldp/stp instruction, it will cost more time.
To improve this, we only add src/dst after load
or store 64 bytes.
Copy 4096 bytes cost on Kunpeng920 (ms):
Without this patch:
memcpy: 143.85 copy_from_user: 172.69 copy_to_user: 199.23
With this patch:
memcpy: 107.12 copy_from_user: 157.50 copy_to_user: 198.85
It's about 25% improvement in memcpy().
Signed-off-by: Yang Yingliang <yangyingli...@huawei.com>
---
arch/arm64/lib/copy_template.S | 36 +++++++++++++++++++---------------
1 file changed, 20 insertions(+), 16 deletions(-)
diff --git a/arch/arm64/lib/copy_template.S b/arch/arm64/lib/copy_template.S
index 488df234c49a..c3cd6f84c9c0 100644
--- a/arch/arm64/lib/copy_template.S
+++ b/arch/arm64/lib/copy_template.S
@@ -152,29 +152,33 @@ D_h .req x14
.p2align L1_CACHE_SHIFT
.Lcpy_body_large:
/* pre-get 64 bytes data. */
- ldp1 A_l, A_h, src, #16
- ldp1 B_l, B_h, src, #16
- ldp1 C_l, C_h, src, #16
- ldp1 D_l, D_h, src, #16
+ ldp2 A_l, A_h, src, #0, #8
+ ldp2 B_l, B_h, src, #16, #24
+ ldp2 C_l, C_h, src, #32, #40
+ ldp2 D_l, D_h, src, #48, #56
+ add src, src, #64
1:
/*
* interlace the load of next 64 bytes data block with store of the last
* loaded 64 bytes data.
*/
- stp1 A_l, A_h, dst, #16
- ldp1 A_l, A_h, src, #16
- stp1 B_l, B_h, dst, #16
- ldp1 B_l, B_h, src, #16
- stp1 C_l, C_h, dst, #16
- ldp1 C_l, C_h, src, #16
- stp1 D_l, D_h, dst, #16
- ldp1 D_l, D_h, src, #16
+ stp2 A_l, A_h, dst, #0, #8
+ ldp2 A_l, A_h, src, #0, #8
+ stp2 B_l, B_h, dst, #16, #24
+ ldp2 B_l, B_h, src, #16, #24
+ stp2 C_l, C_h, dst, #32, #40
+ ldp2 C_l, C_h, src, #32, #40
+ stp2 D_l, D_h, dst, #48, #56
+ ldp2 D_l, D_h, src, #48, #56
+ add src, src, #64
+ add dst, dst, #64
subs count, count, #64
b.ge 1b
- stp1 A_l, A_h, dst, #16
- stp1 B_l, B_h, dst, #16
- stp1 C_l, C_h, dst, #16
- stp1 D_l, D_h, dst, #16
+ stp2 A_l, A_h, dst, #0, #8
+ stp2 B_l, B_h, dst, #16, #24
+ stp2 C_l, C_h, dst, #32, #40
+ stp2 D_l, D_h, dst, #48, #56
+ add dst, dst, #64
tst count, #0x3f
b.ne .Ltail63
--
2.25.1
