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

Denys Vlasenko
2012-03-28T11:23:23Z

On Wednesday 28 March 2012 12:31, roma1390 wrote:
> 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.

> 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

It looks ok - it is a bit faster that original code;
but I expect algorithm #2 will do better.

BTW, please always run test of original code too when you measure speed,
and post both results.

--
vda