[PATCH libdrm 6/9] tests/random: extract test out of xf86drmRandom.c

Jan Vesely jan.vesely at rutgers.edu
Tue Mar 24 15:10:48 PDT 2015


On Sun, 2015-03-22 at 22:03 +0000, Emil Velikov wrote:
> With follow up commits we can clear it up and wire to
> make check
> 
> Signed-off-by: Emil Velikov <emil.l.velikov at gmail.com>
> ---
>  tests/Makefile.am |   3 +-
>  tests/random.c    | 127 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  xf86drmRandom.c   |  67 ++--------------------------
>  3 files changed, 132 insertions(+), 65 deletions(-)
>  create mode 100644 tests/random.c
> 
> diff --git a/tests/Makefile.am b/tests/Makefile.am
> index 392abf5..9b13b2e 100644
> --- a/tests/Makefile.am
> +++ b/tests/Makefile.am
> @@ -29,7 +29,8 @@ LDADD = $(top_builddir)/libdrm.la
>  
>  check_PROGRAMS = \
>  	dristat \
> -	drmstat
> +	drmstat \
> +	random
>  
>  if HAVE_NOUVEAU
>  SUBDIRS += nouveau
> diff --git a/tests/random.c b/tests/random.c
> new file mode 100644
> index 0000000..6dc8386
> --- /dev/null
> +++ b/tests/random.c
> @@ -0,0 +1,127 @@
> +/* xf86drmRandom.c -- "Minimal Standard" PRNG Implementation
> + * Created: Mon Apr 19 08:28:13 1999 by faith at precisioninsight.com
> + *
> + * Copyright 1999 Precision Insight, Inc., Cedar Park, Texas.
> + * All Rights Reserved.
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a
> + * copy of this software and associated documentation files (the "Software"),
> + * to deal in the Software without restriction, including without limitation
> + * the rights to use, copy, modify, merge, publish, distribute, sublicense,
> + * and/or sell copies of the Software, and to permit persons to whom the
> + * Software is furnished to do so, subject to the following conditions:
> + * 
> + * The above copyright notice and this permission notice (including the next
> + * paragraph) shall be included in all copies or substantial portions of the
> + * Software.
> + * 
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
> + * PRECISION INSIGHT AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
> + * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
> + * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
> + * DEALINGS IN THE SOFTWARE.
> + * 
> + * Authors: Rickard E. (Rik) Faith <faith at valinux.com>
> + *
> + * DESCRIPTION
> + *
> + * This file contains a simple, straightforward implementation of the Park
> + * & Miller "Minimal Standard" PRNG [PM88, PMS93], which is a Lehmer
> + * multiplicative linear congruential generator (MLCG) with a period of
> + * 2^31-1.
> + *
> + * This implementation is intended to provide a reliable, portable PRNG
> + * that is suitable for testing a hash table implementation and for
> + * implementing skip lists.
> + *
> + * FUTURE ENHANCEMENTS
> + *
> + * If initial seeds are not selected randomly, two instances of the PRNG
> + * can be correlated.  [Knuth81, pp. 32-33] describes a shuffling technique
> + * that can eliminate this problem.
> + *
> + * If PRNGs are used for simulation, the period of the current
> + * implementation may be too short.  [LE88] discusses methods of combining
> + * MLCGs to produce much longer periods, and suggests some alternative
> + * values for A and M.  [LE90 and Sch92] also provide information on
> + * long-period PRNGs.
> + *
> + * REFERENCES
> + *
> + * [Knuth81] Donald E. Knuth. The Art of Computer Programming.  Volume 2:
> + * Seminumerical Algorithms.  Reading, Massachusetts: Addison-Wesley, 1981.
> + *
> + * [LE88] Pierre L'Ecuyer. "Efficient and Portable Combined Random Number
> + * Generators".  CACM 31(6), June 1988, pp. 742-774.
> + *
> + * [LE90] Pierre L'Ecuyer. "Random Numbers for Simulation". CACM 33(10,
> + * October 1990, pp. 85-97.
> + *
> + * [PM88] Stephen K. Park and Keith W. Miller. "Random Number Generators:
> + * Good Ones are Hard to Find". CACM 31(10), October 1988, pp. 1192-1201.
> + *
> + * [Sch92] Bruce Schneier. "Pseudo-Ransom Sequence Generator for 32-Bit
> + * CPUs".  Dr. Dobb's Journal 17(2), February 1992, pp. 34, 37-38, 40.
> + *
> + * [PMS93] Stephen K. Park, Keith W. Miller, and Paul K. Stockmeyer.  In
> + * "Technical Correspondence: Remarks on Choosing and Implementing Random
> + * Number Generators". CACM 36(7), July 1993, pp. 105-110.
> + *
> + */
> +
> +#include <stdio.h>
> +#include <stdlib.h>
> +
> +#include "xf86drm.h"
> +
> +typedef struct RandomState {
> +    unsigned long magic;
> +    unsigned long a;
> +    unsigned long m;
> +    unsigned long q;		/* m div a */
> +    unsigned long r;		/* m mod a */
> +    unsigned long check;
> +    unsigned long seed;
> +} RandomState;

I think this should also go to an internal header. Otherwise lgtm

> +
> +static void check_period(unsigned long seed)
> +{
> +    unsigned long count = 0;
> +    unsigned long initial;
> +    void          *state;
> +    
> +    state = drmRandomCreate(seed);
> +    initial = drmRandom(state);
> +    ++count;
> +    while (initial != drmRandom(state)) {
> +	if (!++count) break;
> +    }
> +    printf("With seed of %10lu, period = %10lu (0x%08lx)\n",
> +	   seed, count, count);
> +    drmRandomDestroy(state);
> +}
> +
> +int main(void)
> +{
> +    RandomState   *state;
> +    int           i;
> +    unsigned long rand;
> +
> +    state = drmRandomCreate(1);
> +    for (i = 0; i < 10000; i++) {
> +	rand = drmRandom(state);
> +    }
> +    printf("After 10000 iterations: %lu (%lu expected): %s\n",
> +	   rand, state->check,
> +	   rand - state->check ? "*INCORRECT*" : "CORRECT");
> +    drmRandomDestroy(state);
> +
> +    printf("Checking periods...\n");
> +    check_period(1);
> +    check_period(2);
> +    check_period(31415926);
> +    
> +    return 0;
> +}
> diff --git a/xf86drmRandom.c b/xf86drmRandom.c
> index 94922ad..39f3c52 100644
> --- a/xf86drmRandom.c
> +++ b/xf86drmRandom.c
> @@ -74,23 +74,11 @@
>  #include <stdio.h>
>  #include <stdlib.h>
>  
> -#define RANDOM_MAIN 0
> -
> -#if !RANDOM_MAIN
> -# include "xf86drm.h"
> -#endif
> +#include "xf86drm.h"
>  
>  #define RANDOM_MAGIC 0xfeedbeef
>  #define RANDOM_DEBUG 0
>  
> -#if RANDOM_MAIN
> -#define RANDOM_ALLOC malloc
> -#define RANDOM_FREE  free
> -#else
> -#define RANDOM_ALLOC drmMalloc
> -#define RANDOM_FREE  drmFree
> -#endif
> -
>  typedef struct RandomState {
>      unsigned long magic;
>      unsigned long a;
> @@ -101,18 +89,11 @@ typedef struct RandomState {
>      unsigned long seed;
>  } RandomState;
>  
> -#if RANDOM_MAIN
> -extern void          *drmRandomCreate(unsigned long seed);
> -extern int           drmRandomDestroy(void *state);
> -extern unsigned long drmRandom(void *state);
> -extern double        drmRandomDouble(void *state);
> -#endif
> -
>  void *drmRandomCreate(unsigned long seed)
>  {
>      RandomState  *state;
>  
> -    state           = RANDOM_ALLOC(sizeof(*state));
> +    state           = drmMalloc(sizeof(*state));
>      if (!state) return NULL;
>      state->magic    = RANDOM_MAGIC;
>  #if 0
> @@ -140,7 +121,7 @@ void *drmRandomCreate(unsigned long seed)
>  
>  int drmRandomDestroy(void *state)
>  {
> -    RANDOM_FREE(state);
> +    drmFree(state);
>      return 0;
>  }
>  
> @@ -164,45 +145,3 @@ double drmRandomDouble(void *state)
>      
>      return (double)drmRandom(state)/(double)s->m;
>  }
> -
> -#if RANDOM_MAIN
> -static void check_period(unsigned long seed)
> -{
> -    unsigned long count = 0;
> -    unsigned long initial;
> -    void          *state;
> -    
> -    state = drmRandomCreate(seed);
> -    initial = drmRandom(state);
> -    ++count;
> -    while (initial != drmRandom(state)) {
> -	if (!++count) break;
> -    }
> -    printf("With seed of %10lu, period = %10lu (0x%08lx)\n",
> -	   seed, count, count);
> -    drmRandomDestroy(state);
> -}
> -
> -int main(void)
> -{
> -    RandomState   *state;
> -    int           i;
> -    unsigned long rand;
> -
> -    state = drmRandomCreate(1);
> -    for (i = 0; i < 10000; i++) {
> -	rand = drmRandom(state);
> -    }
> -    printf("After 10000 iterations: %lu (%lu expected): %s\n",
> -	   rand, state->check,
> -	   rand - state->check ? "*INCORRECT*" : "CORRECT");
> -    drmRandomDestroy(state);
> -
> -    printf("Checking periods...\n");
> -    check_period(1);
> -    check_period(2);
> -    check_period(31415926);
> -    
> -    return 0;
> -}
> -#endif

-- 
Jan Vesely <jan.vesely at rutgers.edu>
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