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Add more tests for strlcpy()

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I asked ChatGPT o1 for an optimized version of strlcpy() but it couldn't
produce an implementation that didn't crash. Eventually it just gave up.
This commit is contained in:
Justine Tunney 2024-09-13 01:10:14 -07:00
parent e142124730
commit 1260f9d0ed
No known key found for this signature in database
GPG key ID: BE714B4575D6E328
2 changed files with 105 additions and 32 deletions
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51
libc/testlib/benchmark.h
View file

@ -7,24 +7,22 @@ COSMOPOLITAN_C_START_
#define X(x) __expropriate(x)
#define V(x) __veil("r", x)
#define BENCHMARK(ITERATIONS, WORK_PER_RUN, CODE) \
do { \
struct timespec start = timespec_mono(); \
for (int __i = 0; __i < ITERATIONS; ++__i) { \
asm volatile("" ::: "memory"); \
CODE; \
} \
double total_nanos = \
(double)timespec_tonanos(timespec_sub(timespec_mono(), start)); \
double total_work = \
(double)((WORK_PER_RUN) ? (WORK_PER_RUN) : 1) * (ITERATIONS); \
_print_benchmark_result(total_nanos, total_work, ITERATIONS, #CODE); \
#define BENCHMARK(ITERATIONS, WORK_PER_RUN, CODE) \
do { \
struct timespec start = timespec_real(); \
for (int __i = 0; __i < ITERATIONS; ++__i) { \
asm volatile("" ::: "memory"); \
CODE; \
} \
long ns = timespec_tonanos(timespec_sub(timespec_real(), start)); \
_print_benchmark_result(ns, WORK_PER_RUN, ITERATIONS, #CODE); \
} while (0)
static void _print_benchmark_result(double total_nanos, double total_work,
static void _print_benchmark_result(double total_nanos, double work_per_run,
int iterations, const char* code) {
double time_per_op = total_nanos / iterations;
double throughput = total_work / (total_nanos * 1e-9);
double time_per_op = total_nanos / (work_per_run * iterations);
double throughput = work_per_run / (total_nanos / iterations * 1e-9);
const char* throughput_unit;
const char* time_unit;
double time_value;
@ -50,29 +48,32 @@ static void _print_benchmark_result(double total_nanos, double total_work,
} else if (time_per_op >= 1e3) {
time_value = time_per_op / 1e3;
time_unit = "µs";
} else {
} else if (time_per_op >= .01) {
time_value = time_per_op;
time_unit = "ns";
} else {
time_value = time_per_op * 1e3;
time_unit = "ps";
}
// Determine work unit
const char* work_unit;
double work_value = total_work / iterations;
if (work_value >= 1e9) {
work_value /= 1e9;
if (work_per_run >= 1e9) {
work_per_run /= 1e9;
work_unit = "G";
} else if (work_value >= 1e6) {
work_value /= 1e6;
} else if (work_per_run >= 1e6) {
work_per_run /= 1e6;
work_unit = "M";
} else if (work_value >= 1e3) {
work_value /= 1e3;
} else if (work_per_run >= 1e3) {
work_per_run /= 1e3;
work_unit = "K";
} else {
work_unit = " ";
}
printf("%8.2f %-2s %6.2f %s/s %6.2f %s %2dx %s\n", time_value, time_unit,
throughput, throughput_unit, work_value, work_unit, iterations, code);
printf("%8.2f %-2s %8.2f %s/s %6.2f %s %2dx %s\n", time_value, time_unit,
throughput, throughput_unit, work_per_run, work_unit, iterations,
code);
}
COSMOPOLITAN_C_END_

86
test/libc/str/strlcpy_test.c
View file

@ -16,12 +16,71 @@
│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR │
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/assert.h"
#include "libc/calls/calls.h"
#include "libc/intrin/kprintf.h"
#include "libc/intrin/safemacros.h"
#include "libc/mem/gc.h"
#include "libc/mem/mem.h"
#include "libc/runtime/runtime.h"
#include "libc/runtime/sysconf.h"
#include "libc/stdio/rand.h"
#include "libc/str/str.h"
#include "libc/sysv/consts/map.h"
#include "libc/sysv/consts/prot.h"
#include "libc/testlib/benchmark.h"
#include "libc/testlib/ezbench.h"
#include "libc/testlib/testlib.h"
size_t todd(char *dst, const char *src, size_t dsize) {
const char *osrc = src;
size_t nleft = dsize;
if (nleft != 0)
while (--nleft != 0)
if ((*dst++ = *src++) == '\0')
break;
if (nleft == 0) {
if (dsize != 0)
*dst = '\0';
while (*src++)
;
}
return src - osrc - 1;
}
TEST(strlcpy, fuzz) {
int pagesz = sysconf(_SC_PAGESIZE);
char *map1 = (char *)mmap(0, pagesz * 2, PROT_READ | PROT_WRITE,
MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
npassert(map1 != MAP_FAILED);
npassert(!mprotect(map1 + pagesz, pagesz, PROT_NONE));
char *map2 = (char *)mmap(0, pagesz * 2, PROT_READ | PROT_WRITE,
MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
npassert(map2 != MAP_FAILED);
npassert(!mprotect(map2 + pagesz, pagesz, PROT_NONE));
char *map3 = (char *)mmap(0, pagesz * 2, PROT_READ | PROT_WRITE,
MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);
npassert(map3 != MAP_FAILED);
npassert(!mprotect(map3 + pagesz, pagesz, PROT_NONE));
for (int dsize = 1; dsize < 128; ++dsize) {
char *volatile dst1 = map1 + pagesz - dsize;
char *volatile dst2 = map1 + pagesz - dsize;
for (int i = 0; i < dsize; ++i)
dst1[i] = dst2[i] = max(rand() & 255, 1);
for (int ssize = 1; ssize < dsize * 2; ++ssize) {
char *volatile src = map3 + pagesz - (ssize + 1);
for (int i = 0; i < ssize; ++i)
src[i] = max(rand() & 255, 1);
src[ssize] = 0;
ASSERT_EQ(todd(dst1, src, dsize), strlcpy(dst2, src, dsize));
ASSERT_EQ(0, memcmp(dst1, dst2, dsize));
}
}
npassert(!munmap(map3, pagesz * 2));
npassert(!munmap(map2, pagesz * 2));
npassert(!munmap(map1, pagesz * 2));
}
TEST(strlcpy, testEmptyBuffer_doesNothing) {
EXPECT_EQ(5, strlcpy(NULL, "hello", 0));
}
@ -38,12 +97,25 @@ TEST(strlcpy, testShortBuffer_copies) {
EXPECT_STREQ("h", buf);
}
#define N 4096
BENCH(strlcpy, bench) {
char buf[256];
EZBENCH2(
"strlcpy", donothing,
__expropriate(strlcpy(__veil("r", buf), "hello there", sizeof(buf))));
EZBENCH2(
"strncpy", donothing,
__expropriate(strncpy(__veil("r", buf), "hello there", sizeof(buf))));
char dst[N];
char src[N + 1];
printf("\n");
for (int n = 1; n <= N; n *= 2) {
for (int i = 0; i < n; ++i)
src[i] = max(rand() & 255, 1);
src[n] = 0;
BENCHMARK(100, n, X(strlcpy(dst, src, V(N))));
}
printf("\n");
for (int n = 1; n <= N; n *= 2) {
for (int i = 0; i < n; ++i)
src[i] = max(rand() & 255, 1);
src[n] = 0;
BENCHMARK(100, n, X(todd(dst, src, V(N))));
}
}