[patches] Re: Possible PowerPC LIBC optimization

["Conn Clark" <clark@xxxxxxxxxx>]

Here is my corrected benchmark program 

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

#define  NUM_OF_LINES 1024 

/* for a 32k datacache */
int data_cache_flush_array[8193]; 


int thrash_the_cache(int up_down)
{
int i; 

if (up_down) {
 i = 0;
 do{
   data_cache_flush_array[i*8] = data_cache_flush_array [(i+1)*8];
 }while (i++ < NUM_OF_LINES - 2);
} else {
i =  NUM_OF_LINES - 1;
 do{
   data_cache_flush_array[(i+1)*8] = data_cache_flush_array [i*8];
 }while (i-- > 0);
} 

return i; 

} 

int main(void){ 

int x,y,z;
char *mem;
int x1,y1,z1;
char *mem1;
int x2,y2,z2;
char *mem2;
int x3,y3,z3;
char *mem3; 

z= 8192;
do{
data_cache_flush_array[z]=z;
}while(z--); 


srandom(7); 

x = 65535;
x1 = 512;
x2 = 4096;
x3 = 256; 

y = 1000; 

do { 

  thrash_the_cache(1);
  z = random() % x;
  mem = malloc(z);
  if(z) mem[z-1] = 0x3f;
  y1 = 100;
  do {
 do {
    thrash_the_cache(0);
    z1 = random() % x1;
    mem1 = malloc(z1);
    if(z1) mem1[z1-1] = 0x3f;
    y2 = 100;
    do {
      thrash_the_cache(1);
      z2 = random() % x;
      mem2 = malloc(z2);
      if(z2) mem2[z2-1] = 0x3f;
      y3 = 100;
      do {
        thrash_the_cache(0);
        z3 = random() % x3;
        mem3 = malloc(z3);
        if(z3) mem3[z3-1] = 0x3f;
        thrash_the_cache(1);
        free(mem3);
      }while( (--y3)); 

      thrash_the_cache(0);
      free(mem2);
    }while( (--y2)); 

    thrash_the_cache(1);
    free(mem1);
  }while( (--y1)); 


  thrash_the_cache(0);
  free(mem);
}while( (--y)); 


return 1;
} 




Conn Clark writes: 

> There are some further optimizations I'm playing with. I have added one 
> more dcbt to the public_free function. I am also playing around with 
> reorganizing the mp_ data structure to take into account cache filling.  

<SNIP> 

> Conn
> ---------------------------------------
> Conn Clark  
>
> Electronic Systems Technology
> 415 N. Quay Street Building B1     (509)-735-9092 ext 117
> Kennewick, WA. 99336  
>
> Observation: In formal computer science advances are made
> by standing on the shoulders of giants. Linux has proved
> that if there are enough of you, you can advance just as
> far by standing on each others toes.



---------------------------------------
Conn Clark 

Electronic Systems Technology
415 N. Quay Street Building B1     (509)-735-9092 ext 117
Kennewick, WA. 99336 

Observation: In formal computer science advances are made
by standing on the shoulders of giants. Linux has proved
that if there are enough of you, you can advance just as
far by standing on each others toes.