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#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include <cutils/memory.h>
#include <time.h>
/*
* All systems must implement or emulate the rdhwr instruction to read
* the userlocal register. Systems that emulate also return teh count register
* when accessing register $2 so this should work on most systems
*/
#define USE_RDHWR
#ifdef USE_RDHWR
#define UNITS "cycles"
#define SCALE 2 /* Most CPU's */
static inline uint32_t
get_count(void)
{
uint32_t res;
asm volatile (".set push; .set mips32r2; rdhwr %[res],$2; .set pop" : [res] "=r" (res) : : "memory");
return res;
}
#else
#define UNITS "ns"
#define SCALE 1
static inline uint32_t
get_count(void)
{
struct timespec now;
uint32_t res;
clock_gettime(CLOCK_REALTIME, &now);
res = (uint32_t)(now.tv_sec * 1000000000LL + now.tv_nsec);
// printf ("now=%d.%09d res=%d\n", (int)now.tv_sec, (int)now.tv_nsec, res);
return res;
}
#endif
uint32_t overhead;
void
measure_overhead(void)
{
int i;
uint32_t start, stop, delta;
for (i = 0; i < 32; i++) {
start = get_count();
stop = get_count();
delta = stop - start;
if (overhead == 0 || delta < overhead)
overhead = delta;
}
printf("overhead is %d"UNITS"\n", overhead);
}
uint32_t
timeone(void (*fn)(), void *d, uint32_t val, uint32_t bytes)
{
uint32_t start, stop, delta;
start = get_count();
(*fn)(d, val, bytes);
stop = get_count();
delta = stop - start - overhead;
// printf ("start=0x%08x stop=0x%08x delta=0x%08x\n", start, stop, delta);
return delta * SCALE;
}
/* define VERIFY to check that memset only touches the bytes it's supposed to */
/*#define VERIFY*/
/*
* Using a big arena means that memset will most likely miss in the cache
* NB Enabling verification effectively warms up the cache...
*/
#define ARENASIZE 0x1000000
#ifdef VERIFY
char arena[ARENASIZE+8]; /* Allow space for guard words */
#else
char arena[ARENASIZE];
#endif
void
testone(char *tag, void (*fn)(), int trials, int minbytes, int maxbytes, int size, int threshold)
{
int offset;
void *d;
void *p;
uint32_t v, notv = 0;
uint32_t n;
int i, units;
int totalunits = 0, totalbytes = 0, samples = 0;
/* Reset RNG to ensure each test uses same random values */
srand(0); /* FIXME should be able to use some other seed than 0 */
for (i = 0; i < trials; i++) {
n = minbytes + (rand() % (maxbytes-minbytes)); /* How many bytes to do */
offset = ((rand() % (ARENASIZE-n))); /* Where to start */
#ifdef VERIFY
offset += 4; /* Allow space for guard word at beginning */
#endif
v = rand();
/* Adjust alignment and sizes based on transfer size */
switch (size) {
case 1:
v &= 0xff;
notv = ~v & 0xff;
break;
case 2:
v &= 0xffff;
notv = ~v & 0xffff;
offset &= ~1;
n &= ~1;
break;
case 4:
notv = ~v;
offset &= ~3;
n &= ~3;
break;
}
d = &arena[offset];
#ifdef VERIFY
/* Initialise the area and guard words */
for (p = &arena[offset-4]; p < (void *)&arena[offset+n+4]; p = (void *)((uint32_t)p + size)) {
if (size == 1)
*(uint8_t *)p = notv;
else if (size == 2)
*(uint16_t *)p = notv;
else if (size == 4)
*(uint32_t *)p = notv;
}
#endif
units = timeone(fn, d, v, n);
#ifdef VERIFY
/* Check the area and guard words */
for (p = &arena[offset-4]; p < (void *)&arena[offset+n+4]; p = (void *)((uint32_t)p + size)) {
uint32_t got = 0;
if (size == 1)
got = *(uint8_t *)p;
else if (size == 2)
got = *(uint16_t *)p;
else if (size == 4)
got = *(uint32_t *)p;
if (p < (void *)&arena[offset]) {
if (got != notv)
printf ("%s: verify failure: preguard:%p d=%p v=%08x got=%08x n=%d\n", tag, p, d, v, got, n);
}
else if (p < (void *)&arena[offset+n]) {
if (got != v)
printf ("%s: verify failure: arena:%p d=%p v=%08x got=%08x n=%d\n", tag, p, d, v, n);
}
else {
if (got != notv)
printf ("%s: verify failure: postguard:%p d=%p v=%08x got=%08x n=%d\n", tag, p, d, v, n);
}
}
#endif
/* If the cycle count looks reasonable include it in the statistics */
if (units < threshold) {
totalbytes += n;
totalunits += units;
samples++;
}
}
printf("%s: samples=%d avglen=%d avg" UNITS "=%d bp"UNITS"=%g\n",
tag, samples, totalbytes/samples, totalunits/samples, (double)totalbytes/(double)totalunits);
}
extern void android_memset32_dumb(uint32_t* dst, uint32_t value, size_t size);
extern void android_memset16_dumb(uint32_t* dst, uint16_t value, size_t size);
extern void android_memset32_test(uint32_t* dst, uint32_t value, size_t size);
extern void android_memset16_test(uint32_t* dst, uint16_t value, size_t size);
extern void memset_cmips(void* dst, int value, size_t size);
extern void memset_omips(void* dst, int value, size_t size);
int
main(int argc, char **argv)
{
int i;
struct {
char *type;
int trials;
int minbytes, maxbytes;
} *pp, params[] = {
{"small", 10000, 0, 64},
{"medium", 10000, 64, 512},
{"large", 10000, 512, 1280},
{"varied", 10000, 0, 1280},
};
#define NPARAMS (sizeof(params)/sizeof(params[0]))
struct {
char *name;
void (*fn)();
int size;
} *fp, functions[] = {
{"dmemset16", (void (*)())android_memset16_dumb, 2},
{"tmemset16", (void (*)())android_memset16_test, 2},
{"lmemset16", (void (*)())android_memset16, 2},
{"dmemset32", (void (*)())android_memset32_dumb, 4},
{"tmemset32", (void (*)())android_memset32_test, 4},
{"lmemset32", (void (*)())android_memset32, 4},
{"cmemset", (void (*)())memset_cmips, 1},
{"omemset", (void (*)())memset_omips, 1},
{"lmemset", (void (*)())memset, 1},
};
#define NFUNCTIONS (sizeof(functions)/sizeof(functions[0]))
char tag[40];
int threshold;
measure_overhead();
/* Warm up the page cache */
memset(arena, 0xff, ARENASIZE); /* use 0xff now to avoid COW later */
for (fp = functions; fp < &functions[NFUNCTIONS]; fp++) {
(fp->fn)(arena, 0xffffffff, ARENASIZE); /* one call to get the code into Icache */
for (pp = params; pp < ¶ms[NPARAMS]; pp++) {
sprintf(tag, "%10s: %7s %4d-%4d", fp->name, pp->type, pp->minbytes, pp->maxbytes);
/* Set the cycle threshold */
threshold = pp->maxbytes * 4 * 10; /* reasonable for cycles and ns */
testone(tag, fp->fn, pp->trials, pp->minbytes, pp->maxbytes, fp->size, threshold);
}
printf ("\n");
}
return 0;
}
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