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numactl  2.0.8~rc4
Functions
clearcache.c File Reference
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include "clearcache.h"

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Functions

unsigned cache_size (void)
void fallback_clearcache (void)
void clearcache (unsigned char *mem, unsigned size)

Function Documentation

unsigned cache_size ( void  )

Definition at line 11 of file clearcache.c.

{
       unsigned cs = 0;
#ifdef _SC_LEVEL1_DCACHE_SIZE
       cs += sysconf(_SC_LEVEL1_DCACHE_SIZE);
#endif
#ifdef _SC_LEVEL2_DCACHE_SIZE
       cs += sysconf(_SC_LEVEL2_DCACHE_SIZE);
#endif
#ifdef _SC_LEVEL3_DCACHE_SIZE
       cs += sysconf(_SC_LEVEL3_DCACHE_SIZE);
#endif
#ifdef _SC_LEVEL4_DCACHE_SIZE
       cs += sysconf(_SC_LEVEL4_DCACHE_SIZE);
#endif
       if (cs == 0) {
              static int warned;
              if (!warned) {
                     printf("Cannot determine CPU cache size\n");
                     warned = 1;
              }
              cs = 64*1024*1024;
       }
       cs *= 2; /* safety factor */

       return cs;
}

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void clearcache ( unsigned char *  mem,
unsigned  size 
)

Definition at line 55 of file clearcache.c.

{
#if defined(__i386__) || defined(__x86_64__)
       unsigned i, cl, eax, feat;
       /* get clflush unit and feature */
       asm("cpuid" : "=a" (eax), "=b" (cl), "=d" (feat) : "0" (1) : "cx");
       if (!(feat & (1 << 19)))
              fallback_clearcache();
       cl = ((cl >> 8) & 0xff) * 8;
       for (i = 0; i < size; i += cl)
              asm("clflush %0" :: "m" (mem[i]));
#elif defined(__ia64__)
        unsigned long cl, endcl;
        // flush probable 128 byte cache lines (but possibly 64 bytes)
        cl = (unsigned long)mem;
        endcl = (unsigned long)(mem + (size-1));
        for (; cl <= endcl; cl += 64)
                asm ("fc %0" :: "r"(cl) : "memory" );
#else
#warning "Consider adding a clearcache implementation for your architecture"
       fallback_clearcache();
#endif
}

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void fallback_clearcache ( void  )

Definition at line 39 of file clearcache.c.

{
       static unsigned char *clearmem;
       unsigned cs = cache_size();
       unsigned i;

       if (!clearmem)
              clearmem = malloc(cs);
       if (!clearmem) {
              printf("Warning: cannot allocate %u bytes of clear cache buffer\n", cs);
              return;
       }
       for (i = 0; i < cs; i += 32)
              clearmem[i] = 1;
}

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