linux-kernel - Re: [PATCH 0/1] vsprintf: optimize decimal conversion (again)

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Date:	Wed, 28 Mar 2012 13:31:47 +0300
From:	roma1390 <roma1390@...il.com>
To:	Denys Vlasenko <vda.linux@...glemail.com>
CC:	linux-kernel@...r.kernel.org,
	Andrew Morton <akpm@...ux-foundation.org>,
	Douglas W Jones <jones@...uiowa.edu>,
	Michal Nazarewicz <mnazarewicz@...gle.com>
Subject: Re: [PATCH 0/1] vsprintf: optimize decimal conversion (again)

On 2012.03.28 13:13, Denys Vlasenko wrote:
> Third: switch to algorithm #1 and test whether it fares better.
> To do that, go to test_new.c
> and replace
>    #if LONG_MAX>  ((1UL<<31)-1) || LLONG_MAX>  ((1ULL<<63)-1)
> with
>    #if 1   ////LONG_MAX>  ((1UL<<31)-1) || LLONG_MAX>  ((1ULL<<63)-1)
> (there are two instances of this line there),
> then recompile and rerun the test, and post the result.

After applied following diff:


--- test_new.org.c      2012-03-28 13:25:14.000000000 +0300
+++ test_new.c  2012-03-28 13:25:30.000000000 +0300
@@ -7,7 +7,7 @@
   * (with permission from the author, Douglas W. Jones).
   */

-#if LONG_MAX > ((1UL<<31)-1) || LLONG_MAX > ((1ULL<<63)-1)
+#if 1 ////LONG_MAX > ((1UL<<31)-1) || LLONG_MAX > ((1ULL<<63)-1)
  /* Formats correctly any integer in [0, 999999999] */
  static noinline_for_stack
  char *put_dec_full9(char *buf, unsigned q)
@@ -106,7 +106,7 @@
   * Else (if long is 32 bits and long long is 64 bits) we use second one.
   */

-#if LONG_MAX > ((1UL<<31)-1) || LLONG_MAX > ((1ULL<<63)-1)
+#if 1 ///LONG_MAX > ((1UL<<31)-1) || LLONG_MAX > ((1ULL<<63)-1)

  /* First algorithm: generic */


I have following compile output:
$ arm-linux-gnueabi-gcc -O2 -Wall test_new.c -o test_new
test_new.c: In function ‘number’:
test_new.c:118: error: impossible constraint in ‘asm’
test_new.c:118: error: impossible constraint in ‘asm’
test_new.c:118: error: impossible constraint in ‘asm’

but affter this diff:
--- test_new-with-ifdefs.c      2012-03-28 13:29:04.000000000 +0300
+++ test_new.c  2012-03-28 13:29:12.000000000 +0300
@@ -1,4 +1,4 @@
-#include "test_header.c"
+#include "test_header_arm.c"

  /* Decimal conversion is by far the most typical, and is used
   * for /proc and /sys data. This directly impacts e.g. top performance

compiles fine.

result are:
./test_new2
Conversions per second: 8:5420000 123:4452000 123456:3556000 12345678:3368000 
123456789:2904000 2^32:2412000 2^64:1556000
Conversions per second: 8:5428000 123:4500000 123456:3644000 12345678:3328000 
123456789:2832000 2^32:2408000 2^64:1572000
Conversions per second: 8:5372000 123:4396000 123456:3644000 12345678:3368000 
123456789:2900000 2^32:2392000 2^64:1532000
Conversions per second: 8:5424000 123:4500000 123456:3608000 12345678:3284000 
123456789:2896000 2^32:2416000 2^64:1572000

btw: previovios version (test_new) still running, now is at:
Tested 2446852096

roma1390

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