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authorZhao Yakui <yakui.zhao@intel.com>2010-10-08 09:47:33 +0800
committerH. Peter Anvin <hpa@zytor.com>2010-10-07 21:23:09 -0700
commit68f4d5a00adaab33b136fce2c72d5c377b39b0b0 (patch)
treedfd0404f760ca8ab117117e4388885255b47013b /arch/x86/boot
parentcb655d0f3d57c23db51b981648e452988c0223f9 (diff)
x86, setup: Use string copy operation to optimze copy in kernel compression
The kernel decompression code parses the ELF header and then copies the segment to the corresponding destination. Currently it uses slow byte-copy code. This patch makes it use the string copy operations instead. In the test the copy performance can be improved very significantly after using the string copy operation mechanism. 1. The copy time can be reduced from 150ms to 20ms on one Atom machine 2. The copy time can be reduced about 80% on another machine The time is reduced from 7ms to 1.5ms when using 32-bit kernel. The time is reduced from 10ms to 2ms when using 64-bit kernel. Signed-off-by: Zhao Yakui <yakui.zhao@intel.com> LKML-Reference: <1286502453-7043-1-git-send-email-yakui.zhao@intel.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Diffstat (limited to 'arch/x86/boot')
-rw-r--r--arch/x86/boot/compressed/misc.c29
1 files changed, 23 insertions, 6 deletions
diff --git a/arch/x86/boot/compressed/misc.c b/arch/x86/boot/compressed/misc.c
index 8f7bef8e9fff..23f315c9f215 100644
--- a/arch/x86/boot/compressed/misc.c
+++ b/arch/x86/boot/compressed/misc.c
@@ -229,18 +229,35 @@ void *memset(void *s, int c, size_t n)
ss[i] = c;
return s;
}
-
+#ifdef CONFIG_X86_32
void *memcpy(void *dest, const void *src, size_t n)
{
- int i;
- const char *s = src;
- char *d = dest;
+ int d0, d1, d2;
+ asm volatile(
+ "rep ; movsl\n\t"
+ "movl %4,%%ecx\n\t"
+ "rep ; movsb\n\t"
+ : "=&c" (d0), "=&D" (d1), "=&S" (d2)
+ : "0" (n >> 2), "g" (n & 3), "1" (dest), "2" (src)
+ : "memory");
- for (i = 0; i < n; i++)
- d[i] = s[i];
return dest;
}
+#else
+void *memcpy(void *dest, const void *src, size_t n)
+{
+ long d0, d1, d2;
+ asm volatile(
+ "rep ; movsq\n\t"
+ "movq %4,%%rcx\n\t"
+ "rep ; movsb\n\t"
+ : "=&c" (d0), "=&D" (d1), "=&S" (d2)
+ : "0" (n >> 3), "g" (n & 7), "1" (dest), "2" (src)
+ : "memory");
+ return dest;
+}
+#endif
static void error(char *x)
{