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Include <unistd.h> and <sys/resource.h>.

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(KB): New macro.
(big): Lower the size to 64*MB.  Should be enough for another year... ;-)
(gettime): Fix typo and lower the assumed cache-line size from 64
	to 8 bytes just to be safe across platforms.
(measure_init): Lower N from 1000 to 100.
	(cursor): Add some padding between each unw_cursor_t to avoid
		benefitting from cache-line sharing.
	(uc): Likewise.
	Warm up the TLB before measuring the cold-cache cases.
(main): Unlimit the max. stack-size just in case.
	Write to "big" to ensure it's backed by real memory
	(not just by the zero page).

(Logical change 1.194)
This commit is contained in:
hp.com!davidm 2004-03-30 22:57:06 +00:00
parent a4fef7cd62
commit 3be31f5dcb
1 changed files with 39 additions and 14 deletions
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53
tests/Gperf-simple.c
View file

@ -24,11 +24,14 @@ WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
#include <memory.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <time.h>
#include <libunwind.h>
#include <sys/resource.h>
#define panic(args...) \
do { fprintf (stderr, args); exit (-1); } while (0)
@ -37,9 +40,10 @@ long dummy;
static long iterations = 10000;
static int maxlevel = 100;
#define KB 1024
#define MB (1024*1024)
static char big[512*MB];
static char big[64*MB]; /* should be >> max. cache size */
static inline double
gettime (void)
@ -124,19 +128,29 @@ sum (void *buf, size_t size)
char *cp = buf;
size_t i;
for (i = 0; i < size; i += 64)
s += *cp++;
for (i = 0; i < size; i += 8)
s += cp[i];
return s;
}
static void
measure_init (void)
{
# define N 1000
# define M 10
# define N 100
# define M 10 /* must be at least 2 to get steady-state */
double stop, start, get_cold, get_warm, init_cold, init_warm, delta;
unw_cursor_t cursor[N];
unw_context_t uc[N];
struct
{
unw_cursor_t c;
char padding[1024]; /* should be > 2 * max. cacheline size */
}
cursor[N];
struct
{
unw_context_t uc;
char padding[1024]; /* should be > 2 * max. cacheline size */
}
uc[N];
int i, j;
/* Run each test M times and take the minimum to filter out noise
@ -146,24 +160,27 @@ measure_init (void)
get_cold = 1e99;
for (j = 0; j < M; ++j)
{
dummy += sum (big, sizeof (big)); /* flush the cache */
dummy += sum (big, sizeof (big)); /* flush the cache */
for (i = 0; i < N; ++i)
uc[i].padding[511] = i; /* warm up the TLB */
start = gettime ();
for (i = 0; i < N; ++i)
unw_getcontext (&uc[i]);
unw_getcontext (&uc[i].uc);
stop = gettime ();
delta = (stop - start) / N;
if (delta < get_cold)
get_cold = delta;
}
//exit (0);
init_cold = 1e99;
for (j = 0; j < M; ++j)
{
dummy += sum (big, sizeof (big)); /* flush cache */
for (i = 0; i < N; ++i)
uc[i].padding[511] = i; /* warm up the TLB */
start = gettime ();
for (i = 0; i < N; ++i)
unw_init_local (&cursor[i], &uc[i]);
unw_init_local (&cursor[i].c, &uc[i].uc);
stop = gettime ();
delta = (stop - start) / N;
if (delta < init_cold)
@ -175,7 +192,7 @@ measure_init (void)
{
start = gettime ();
for (i = 0; i < N; ++i)
unw_getcontext (&uc[0]);
unw_getcontext (&uc[0].uc);
stop = gettime ();
delta = (stop - start) / N;
if (delta < get_warm)
@ -187,7 +204,7 @@ measure_init (void)
{
start = gettime ();
for (i = 0; i < N; ++i)
unw_init_local (&cursor[0], &uc[0]);
unw_init_local (&cursor[0].c, &uc[0].uc);
stop = gettime ();
delta = (stop - start) / N;
if (delta < init_warm)
@ -203,6 +220,14 @@ measure_init (void)
int
main (int argc, char **argv)
{
struct rlimit rlim;
rlim.rlim_cur = RLIM_INFINITY;
rlim.rlim_max = RLIM_INFINITY;
setrlimit (RLIMIT_STACK, &rlim);
memset (big, 0xaa, sizeof (big));
if (argc > 1)
{
maxlevel = atol (argv[1]);