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authorAnton Blanchard <anton@samba.org>2010-02-10 14:56:26 +0000
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2010-02-17 14:03:16 +1100
commit789c299ca280f96368c0296b739e89c0bb232f8a (patch)
treec14611126d351e6b69cb2db26afd4fbd77b3763f /arch/powerpc/lib
parent63e6c5b8102af7df7a5e1cebbd865d711645886a (diff)
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powerpc: Improve 64bit copy_tofrom_user
Here is a patch from Paul Mackerras that improves the ppc64 copy_tofrom_user. The loop now does 32 bytes at a time and as well as pairing loads and stores. A quick test case that reads 8kB over and over shows the improvement: POWER6: 53% faster POWER7: 51% faster #define _XOPEN_SOURCE 500 #include <stdlib.h> #include <stdio.h> #include <unistd.h> #include <fcntl.h> #include <sys/types.h> #include <sys/stat.h> #define BUFSIZE (8 * 1024) #define ITERATIONS 10000000 int main() { char tmpfile[] = "/tmp/copy_to_user_testXXXXXX"; int fd; char *buf[BUFSIZE]; unsigned long i; fd = mkstemp(tmpfile); if (fd < 0) { perror("open"); exit(1); } if (write(fd, buf, BUFSIZE) != BUFSIZE) { perror("open"); exit(1); } for (i = 0; i < 10000000; i++) { if (pread(fd, buf, BUFSIZE, 0) != BUFSIZE) { perror("pread"); exit(1); } } unlink(tmpfile); return 0; } Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch/powerpc/lib')
-rw-r--r--arch/powerpc/lib/copyuser_64.S80
1 files changed, 57 insertions, 23 deletions
diff --git a/arch/powerpc/lib/copyuser_64.S b/arch/powerpc/lib/copyuser_64.S
index 693b14a..578b625 100644
--- a/arch/powerpc/lib/copyuser_64.S
+++ b/arch/powerpc/lib/copyuser_64.S
@@ -44,37 +44,55 @@ BEGIN_FTR_SECTION
andi. r0,r4,7
bne .Lsrc_unaligned
END_FTR_SECTION_IFCLR(CPU_FTR_UNALIGNED_LD_STD)
- srdi r7,r5,4
-20: ld r9,0(r4)
- addi r4,r4,-8
- mtctr r7
- andi. r5,r5,7
- bf cr7*4+0,22f
- addi r3,r3,8
- addi r4,r4,8
- mr r8,r9
- blt cr1,72f
-21: ld r9,8(r4)
-70: std r8,8(r3)
-22: ldu r8,16(r4)
-71: stdu r9,16(r3)
+ blt cr1,.Ldo_tail /* if < 16 bytes to copy */
+ srdi r0,r5,5
+ cmpdi cr1,r0,0
+20: ld r7,0(r4)
+220: ld r6,8(r4)
+ addi r4,r4,16
+ mtctr r0
+ andi. r0,r5,0x10
+ beq 22f
+ addi r3,r3,16
+ addi r4,r4,-16
+ mr r9,r7
+ mr r8,r6
+ beq cr1,72f
+21: ld r7,16(r4)
+221: ld r6,24(r4)
+ addi r4,r4,32
+70: std r9,0(r3)
+270: std r8,8(r3)
+22: ld r9,0(r4)
+222: ld r8,8(r4)
+71: std r7,16(r3)
+271: std r6,24(r3)
+ addi r3,r3,32
bdnz 21b
-72: std r8,8(r3)
+72: std r9,0(r3)
+272: std r8,8(r3)
+ andi. r5,r5,0xf
beq+ 3f
- addi r3,r3,16
+ addi r4,r4,16
.Ldo_tail:
- bf cr7*4+1,1f
-23: lwz r9,8(r4)
+ addi r3,r3,16
+ bf cr7*4+0,246f
+244: ld r9,0(r4)
+ addi r4,r4,8
+245: std r9,0(r3)
+ addi r3,r3,8
+246: bf cr7*4+1,1f
+23: lwz r9,0(r4)
addi r4,r4,4
73: stw r9,0(r3)
addi r3,r3,4
1: bf cr7*4+2,2f
-44: lhz r9,8(r4)
+44: lhz r9,0(r4)
addi r4,r4,2
74: sth r9,0(r3)
addi r3,r3,2
2: bf cr7*4+3,3f
-45: lbz r9,8(r4)
+45: lbz r9,0(r4)
75: stb r9,0(r3)
3: li r3,0
blr
@@ -220,7 +238,9 @@ END_FTR_SECTION_IFCLR(CPU_FTR_UNALIGNED_LD_STD)
131:
addi r3,r3,8
120:
+320:
122:
+322:
124:
125:
126:
@@ -229,9 +249,11 @@ END_FTR_SECTION_IFCLR(CPU_FTR_UNALIGNED_LD_STD)
129:
133:
addi r3,r3,8
-121:
132:
addi r3,r3,8
+121:
+321:
+344:
134:
135:
138:
@@ -303,18 +325,22 @@ END_FTR_SECTION_IFCLR(CPU_FTR_UNALIGNED_LD_STD)
183:
add r3,r3,r7
b 1f
+371:
180:
addi r3,r3,8
171:
177:
addi r3,r3,8
-170:
-172:
+370:
+372:
176:
178:
addi r3,r3,4
185:
addi r3,r3,4
+170:
+172:
+345:
173:
174:
175:
@@ -341,11 +367,19 @@ END_FTR_SECTION_IFCLR(CPU_FTR_UNALIGNED_LD_STD)
.section __ex_table,"a"
.align 3
.llong 20b,120b
+ .llong 220b,320b
.llong 21b,121b
+ .llong 221b,321b
.llong 70b,170b
+ .llong 270b,370b
.llong 22b,122b
+ .llong 222b,322b
.llong 71b,171b
+ .llong 271b,371b
.llong 72b,172b
+ .llong 272b,372b
+ .llong 244b,344b
+ .llong 245b,345b
.llong 23b,123b
.llong 73b,173b
.llong 44b,144b