The patch titled
Subject: lib/vsprintf.c: improve put_dec_trunc8 slightly
has been added to the -mm tree. Its filename is
lib-vsprintfc-improve-put_dec_trunc8-slightly.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/lib-vsprintfc-improve-put_dec_trunc8-slightly.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/lib-vsprintfc-improve-put_dec_trunc8-slightly.patch
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------------------------------------------------------
From: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>
Subject: lib/vsprintf.c: improve put_dec_trunc8 slightly
I hadn't had enough coffee when I wrote this. Currently, the final
increment of buf depends on the value loaded from the table, and
causes gcc to emit a cmov immediately before the return. It is smarter
to let it depend on r, since the increment can then be computed in
parallel with the final load/store pair. It also shaves 16 bytes of
.text.
Signed-off-by: Rasmus Villemoes <linux@xxxxxxxxxxxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
lib/vsprintf.c | 10 ++++------
1 file changed, 4 insertions(+), 6 deletions(-)
diff -puN lib/vsprintf.c~lib-vsprintfc-improve-put_dec_trunc8-slightly lib/vsprintf.c
--- a/lib/vsprintf.c~lib-vsprintfc-improve-put_dec_trunc8-slightly
+++ a/lib/vsprintf.c
@@ -165,9 +165,9 @@ static const u16 decpair[100] = {
/*
* This will print a single '0' even if r == 0, since we would
- * immediately jump to out_r where two 0s would be written and one of
- * them then discarded. This is needed by ip4_string below. All other
- * callers pass a non-zero value of r.
+ * immediately jump to out_r where two 0s would be written but only
+ * one of them accounted for in buf. This is needed by ip4_string
+ * below. All other callers pass a non-zero value of r.
*/
static noinline_for_stack
char *put_dec_trunc8(char *buf, unsigned r)
@@ -206,9 +206,7 @@ out_q:
out_r:
/* 1 <= r < 100 */
*((u16 *)buf) = decpair[r];
- buf += 2;
- if (buf[-1] == '0')
- buf--;
+ buf += r < 10 ? 1 : 2;
return buf;
}
_
Patches currently in -mm which might be from linux@xxxxxxxxxxxxxxxxxx are
include-linux-remove-empty-conditionals.patch
lib-vsprintfc-eliminate-some-branches.patch
lib-vsprintfc-reduce-stack-use-in-number.patch
lib-vsprintfc-eliminate-duplicate-hex-string-array.patch
lib-vsprintfc-another-small-hack.patch
lib-vsprintfc-fix-potential-null-deref-in-hex_string.patch
lib-string_helpersc-refactor-string_escape_mem.patch
lib-string_helpersc-change-semantics-of-string_escape_mem.patch
lib-string_helpersc-change-semantics-of-string_escape_mem-fix.patch
lib-string_helpersc-change-semantics-of-string_escape_mem-fix-fix.patch
linux-bitmaph-improve-bitmap_lastfirst_word_mask.patch
lib-find__bit-reimplementation.patch
lib-find__bit-reimplementation-fix.patch
lib-move-find_last_bit-to-lib-find_next_bitc.patch
lib-rename-lib-find_next_bitc-to-lib-find_bitc.patch
lib-vsprintfc-even-faster-decimal-conversion.patch
lib-vsprintfc-even-faster-decimal-conversion-fix.patch
lib-vsprintfc-improve-put_dec_trunc8-slightly.patch
binfmt_misc-simplify-entry_status.patch
binfmt_misc-simplify-entry_status-fix.patch
rtc-mc13xxx-fix-obfuscated-and-wrong-format-string.patch
lib-lz4-pull-out-constant-tables.patch
linux-next.patch
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