Re: [PATCH] lib/lz4: make arrays static const, reduces object code size

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Le 22/09/2017 à 00:19, Colin King a écrit :
From: Colin Ian King <colin.king@xxxxxxxxxxxxx>

Don't populate the read-only arrays dec32table and dec64table on the
stack, instead make them both static const.  Makes the object code
smaller by over 10K bytes:
10k? Wouaouh! This is way much more than what you usually win with such patches.
I assume we must thanks FORCE_INLINE in this case.
Nice catch!

CJ

Before:
    text	   data	    bss	    dec	    hex	filename
   31500	      0	      0	  31500	   7b0c	lib/lz4/lz4_decompress.o

After:
    text	   data	    bss	    dec	    hex	filename
   20237	    176	      0	  20413	   4fbd	lib/lz4/lz4_decompress.o

(gcc version 7.2.0 x86_64)

Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
---
  lib/lz4/lz4_decompress.c | 4 ++--
  1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/lz4/lz4_decompress.c b/lib/lz4/lz4_decompress.c
index bd3574312b82..141734d255e4 100644
--- a/lib/lz4/lz4_decompress.c
+++ b/lib/lz4/lz4_decompress.c
@@ -85,8 +85,8 @@ static FORCE_INLINE int LZ4_decompress_generic(
  	const BYTE * const lowLimit = lowPrefix - dictSize;
const BYTE * const dictEnd = (const BYTE *)dictStart + dictSize;
-	const unsigned int dec32table[] = { 0, 1, 2, 1, 4, 4, 4, 4 };
-	const int dec64table[] = { 0, 0, 0, -1, 0, 1, 2, 3 };
+	static const unsigned int dec32table[] = { 0, 1, 2, 1, 4, 4, 4, 4 };
+	static const int dec64table[] = { 0, 0, 0, -1, 0, 1, 2, 3 };
const int safeDecode = (endOnInput == endOnInputSize);
  	const int checkOffset = ((safeDecode) && (dictSize < (int)(64 * KB)));


--
To unsubscribe from this list: send the line "unsubscribe kernel-janitors" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html



[Index of Archives]     [Kernel Development]     [Kernel Announce]     [Kernel Newbies]     [Linux Networking Development]     [Share Photos]     [IDE]     [Security]     [Git]     [Netfilter]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Device Mapper]

  Powered by Linux