[PATCH 1/1] boot: Enhance performance by eliminating unnecessary calls to printf()

Jean Sacren
2011-06-06T00:40:43Z

Hi,

Repeated calling to printf() for 13 times is a dire waste of CPU cycles.
For performance, combine all those calls into one while source code
formatting is preserved for readability.

Compile tested only.

Signed-off-by: Jean Sacren <sakiwit@gmail.com>
---
arch/x86/boot/compressed/mkpiggy.c | 30 ++++++++++++++++--------------
1 files changed, 16 insertions(+), 14 deletions(-)

diff --git a/arch/x86/boot/compressed/mkpiggy.c b/arch/x86/boot/compressed/mkpiggy.c
index 46a8238..0b6d82c 100644
--- a/arch/x86/boot/compressed/mkpiggy.c
+++ b/arch/x86/boot/compressed/mkpiggy.c
@@ -44,6 +44,7 @@ int main(int argc, char *argv[])
long ilen;
unsigned long offs;
FILE *f;
+ char *msg;

if (argc < 2) {
fprintf(stderr, "Usage: %s compressed_file\n", argv[0]);
@@ -82,21 +83,22 @@ int main(int argc, char *argv[])
offs += 64*1024 + 128; /* Add 64K + 128 bytes slack */
offs = (offs+4095) & ~4095; /* Round to a 4K boundary */

- printf(".section \".rodata..compressed\",\"a\",@progbits\n");
- printf(".globl z_input_len\n");
- printf("z_input_len = %lu\n", ilen);
- printf(".globl z_output_len\n");
- printf("z_output_len = %lu\n", (unsigned long)olen);
- printf(".globl z_extract_offset\n");
- printf("z_extract_offset = 0x%lx\n", offs);
/* z_extract_offset_negative allows simplification of head_32.S */
- printf(".globl z_extract_offset_negative\n");
- printf("z_extract_offset_negative = -0x%lx\n", offs);
-
- printf(".globl input_data, input_data_end\n");
- printf("input_data:\n");
- printf(".incbin \"%s\"\n", argv[1]);
- printf("input_data_end:\n");
+ msg = ".section \".rodata..compressed\",\"a\",@progbits\n"
+ ".globl z_input_len\n"
+ "z_input_len = %lu\n"
+ ".globl z_output_len\n"
+ "z_output_len = %lu\n"
+ ".globl z_extract_offset\n"
+ "z_extract_offset = 0x%lx\n"
+ ".globl z_extract_offset_negative\n"
+ "z_extract_offset_negative = -0x%lx\n"
+ ".globl input_data, input_data_end\n"
+ "input_data:\n"
+ ".incbin \"%s\"\n"
+ "input_data_end:\n";
+
+ printf(msg, ilen, (unsigned long)olen, offs, offs, argv[1]);

return 0;
}
--
1.7.2.2

--
Jean Sacren