Re: [patch, mips] Improved memset for MIPS

[Steve Ellcey <sellcey at mips dot com>]

On Fri, 2013-09-06 at 13:12 -0400, Carlos O'Donell wrote:

> Are you able to post this test program for posterity along with
> your patches?

I have attached it to this email.  I compile with -UVERIFY when doing
benchmarks and with -DVERIFY when I am doing correctness testing.  On
one of my 74k boards the old memset took 63.409 seconds and the new one
took 45.577 seconds.  I played with different prefetch hints too while
benchmarking but the prepare-to-store one is the fastest.


> Just run `make bench', wait a while, and compare results before and after.
> 
> Look at bench/README for more details.

I tried running it but all the tests failed with messages like this:


Running /home/sellcey/gcc/memset/obj-mipsisa32r2el-linux-gnu/glibc/obj_default/benchtests/bench-bcopy
/home/sellcey/gcc/memset/obj-mipsisa32r2el-linux-gnu/glibc/obj_default/elf/ld.so.1: 1: /home/sellcey/gcc/memset/obj-mipsisa32r2el-linux-gnu/glibc/obj_default/elf/ld.so.1: ^?ELF^A^A^A^C^H^Aï^O4~\ï: not found
/home/sellcey/gcc/memset/obj-mipsisa32r2el-linux-gnu/glibc/obj_default/elf/ld.so.1: 2: /home/sellcey/gcc/memset/obj-mipsisa32r2el-linux-gnu/glibc/obj_default/elf/ld.so.1: Syntax error: "(" unexpected


I am not quite sure what to make of this, it seems to be using the right
ld.so.1 but I am not sure what it is that is 'not found'  Could this be
related to the issue of installing the latest libgcc and libstdc++ in
default locations? (glibc 2.18 wiki section 5.1.1)  I built glibc with a
GCC from a non-standard location so the libgcc and libstdc++ for that
compiler are not in the standard locations.

Steve Ellcey
sellcey@mips.com

#include <string.h>
#include <stdio.h>
#include <stdlib.h>

#define STARTOFFSET   64
#define MAXOFFSET 128
#ifdef VERIFY
#define SIZE 1024
#define MAXSETSIZE 520
#define SIZEINC 1
#define OFFSETINC 1
#else
#define SIZE 102400
#define MAXSETSIZE 51200
#define SIZEINC 1
#define OFFSETINC 1
#endif

/* MEMSETVAL must be a value that VAL will never return.  */
#define VAL(N) ((N % 6) + 13)
#define MEMSETVAL 0
signed char dst[SIZE];

extern void *MEMSET_NAME(void *, int, size_t);

test(int offset, int size)
{
  int i;
  char *x;

#ifdef VERIFY
  for (i = 0; i < SIZE; i++) {
    dst[i] = VAL(i);
  }
#endif
  MEMSET_NAME(&dst[offset], MEMSETVAL, size);
#ifdef VERIFY
  /* printf("Test memset of dst[%d] (0x%p), size = %d\n", offset, &dst[offset], size); */
  for (i = 0; i < offset; i++) {
      if (dst[i] != VAL(i))
	printf("FAIL, dst[%d] got changed before it should be (%d instead of %d)\n", i, VAL(i), dst[i]);
  }
  for (i = offset; i < offset+size; i++) {
      if (dst[i] != MEMSETVAL)
	printf("FAIL, dst[%d] was not changed when it should be (%d instead of %d)\n", i, dst[i], MEMSETVAL);
  }
  for (i = offset+size; i < SIZE; i++) {
      if (dst[i] != VAL(i))
	 printf("FAIL, dst[%d] got changed after it should be (%d instead of %d)\n", i, dst[i], VAL(i));
  }
#endif
}

main()
{
  int i, j;
  for (i = STARTOFFSET; i < MAXOFFSET; i = i + OFFSETINC) {
    for (j = 1; j < MAXSETSIZE; j = j + SIZEINC) {
      test(i, j);
    }
  }
  exit(0);
}