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tests/fp: add fp-bench

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These microbenchmarks will allow us to measure the performance impact of
FP emulation optimizations. Note that we can measure both directly the impact
on the softfloat functions (with "-t soft"), or the impact on an
emulated workload (call with "-t host" and run under qemu user-mode).

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Emilio G. Cota <cota@braap.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
This commit is contained in:
Emilio G. Cota 2018-03-28 13:57:56 -04:00 committed by Alex Bennée
parent 315df0d193
commit 25f539f359
3 changed files with 635 additions and 1 deletions
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1
tests/fp/.gitignore vendored
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@ -1 +1,2 @@
fp-test
fp-bench

5
tests/fp/Makefile
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@ -553,7 +553,7 @@ TF_OBJS_LIB += $(TF_OBJS_WRITECASE)
TF_OBJS_LIB += testLoops_common.o
TF_OBJS_LIB += $(TF_OBJS_TEST)
BINARIES := fp-test$(EXESUF)
BINARIES := fp-test$(EXESUF) fp-bench$(EXESUF)
# everything depends on config-host.h because platform.h includes it
all: $(BUILD_DIR)/config-host.h
@ -590,10 +590,13 @@ $(TF_OBJS_LIB) slowfloat.o: %.o: $(TF_SOURCE_DIR)/%.c
libtestfloat.a: $(TF_OBJS_LIB)
fp-bench$(EXESUF): fp-bench.o $(QEMU_SOFTFLOAT_OBJ) $(LIBQEMUUTIL)
clean:
rm -f *.o *.d $(BINARIES)
rm -f *.gcno *.gcda *.gcov
rm -f fp-test$(EXESUF)
rm -f fp-bench$(EXESUF)
rm -f libsoftfloat.a
rm -f libtestfloat.a

630
tests/fp/fp-bench.c Normal file
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@ -0,0 +1,630 @@
/*
* fp-bench.c - A collection of simple floating point microbenchmarks.
*
* Copyright (C) 2018, Emilio G. Cota <cota@braap.org>
*
* License: GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*/
#ifndef HW_POISON_H
#error Must define HW_POISON_H to work around TARGET_* poisoning
#endif
#include "qemu/osdep.h"
#include <math.h>
#include <fenv.h>
#include "qemu/timer.h"
#include "fpu/softfloat.h"
/* amortize the computation of random inputs */
#define OPS_PER_ITER 50000
#define MAX_OPERANDS 3
#define SEED_A 0xdeadfacedeadface
#define SEED_B 0xbadc0feebadc0fee
#define SEED_C 0xbeefdeadbeefdead
enum op {
OP_ADD,
OP_SUB,
OP_MUL,
OP_DIV,
OP_FMA,
OP_SQRT,
OP_CMP,
OP_MAX_NR,
};
static const char * const op_names[] = {
[OP_ADD] = "add",
[OP_SUB] = "sub",
[OP_MUL] = "mul",
[OP_DIV] = "div",
[OP_FMA] = "mulAdd",
[OP_SQRT] = "sqrt",
[OP_CMP] = "cmp",
[OP_MAX_NR] = NULL,
};
enum precision {
PREC_SINGLE,
PREC_DOUBLE,
PREC_FLOAT32,
PREC_FLOAT64,
PREC_MAX_NR,
};
enum rounding {
ROUND_EVEN,
ROUND_ZERO,
ROUND_DOWN,
ROUND_UP,
ROUND_TIEAWAY,
N_ROUND_MODES,
};
static const char * const round_names[] = {
[ROUND_EVEN] = "even",
[ROUND_ZERO] = "zero",
[ROUND_DOWN] = "down",
[ROUND_UP] = "up",
[ROUND_TIEAWAY] = "tieaway",
};
enum tester {
TESTER_SOFT,
TESTER_HOST,
TESTER_MAX_NR,
};
static const char * const tester_names[] = {
[TESTER_SOFT] = "soft",
[TESTER_HOST] = "host",
[TESTER_MAX_NR] = NULL,
};
union fp {
float f;
double d;
float32 f32;
float64 f64;
uint64_t u64;
};
struct op_state;
typedef float (*float_func_t)(const struct op_state *s);
typedef double (*double_func_t)(const struct op_state *s);
union fp_func {
float_func_t float_func;
double_func_t double_func;
};
typedef void (*bench_func_t)(void);
struct op_desc {
const char * const name;
};
#define DEFAULT_DURATION_SECS 1
static uint64_t random_ops[MAX_OPERANDS] = {
SEED_A, SEED_B, SEED_C,
};
static float_status soft_status;
static enum precision precision;
static enum op operation;
static enum tester tester;
static uint64_t n_completed_ops;
static unsigned int duration = DEFAULT_DURATION_SECS;
static int64_t ns_elapsed;
/* disable optimizations with volatile */
static volatile union fp res;
/*
* From: https://en.wikipedia.org/wiki/Xorshift
* This is faster than rand_r(), and gives us a wider range (RAND_MAX is only
* guaranteed to be >= INT_MAX).
*/
static uint64_t xorshift64star(uint64_t x)
{
x ^= x >> 12; /* a */
x ^= x << 25; /* b */
x ^= x >> 27; /* c */
return x * UINT64_C(2685821657736338717);
}
static void update_random_ops(int n_ops, enum precision prec)
{
int i;
for (i = 0; i < n_ops; i++) {
uint64_t r = random_ops[i];
if (prec == PREC_SINGLE || PREC_FLOAT32) {
do {
r = xorshift64star(r);
} while (!float32_is_normal(r));
} else if (prec == PREC_DOUBLE || PREC_FLOAT64) {
do {
r = xorshift64star(r);
} while (!float64_is_normal(r));
} else {
g_assert_not_reached();
}
random_ops[i] = r;
}
}
static void fill_random(union fp *ops, int n_ops, enum precision prec,
bool no_neg)
{
int i;
for (i = 0; i < n_ops; i++) {
switch (prec) {
case PREC_SINGLE:
case PREC_FLOAT32:
ops[i].f32 = make_float32(random_ops[i]);
if (no_neg && float32_is_neg(ops[i].f32)) {
ops[i].f32 = float32_chs(ops[i].f32);
}
/* raise the exponent to limit the frequency of denormal results */
ops[i].f32 |= 0x40000000;
break;
case PREC_DOUBLE:
case PREC_FLOAT64:
ops[i].f64 = make_float64(random_ops[i]);
if (no_neg && float64_is_neg(ops[i].f64)) {
ops[i].f64 = float64_chs(ops[i].f64);
}
/* raise the exponent to limit the frequency of denormal results */
ops[i].f64 |= LIT64(0x4000000000000000);
break;
default:
g_assert_not_reached();
}
}
}
/*
* The main benchmark function. Instead of (ab)using macros, we rely
* on the compiler to unfold this at compile-time.
*/
static void bench(enum precision prec, enum op op, int n_ops, bool no_neg)
{
int64_t tf = get_clock() + duration * 1000000000LL;
while (get_clock() < tf) {
union fp ops[MAX_OPERANDS];
int64_t t0;
int i;
update_random_ops(n_ops, prec);
switch (prec) {
case PREC_SINGLE:
fill_random(ops, n_ops, prec, no_neg);
t0 = get_clock();
for (i = 0; i < OPS_PER_ITER; i++) {
float a = ops[0].f;
float b = ops[1].f;
float c = ops[2].f;
switch (op) {
case OP_ADD:
res.f = a + b;
break;
case OP_SUB:
res.f = a - b;
break;
case OP_MUL:
res.f = a * b;
break;
case OP_DIV:
res.f = a / b;
break;
case OP_FMA:
res.f = fmaf(a, b, c);
break;
case OP_SQRT:
res.f = sqrtf(a);
break;
case OP_CMP:
res.u64 = isgreater(a, b);
break;
default:
g_assert_not_reached();
}
}
break;
case PREC_DOUBLE:
fill_random(ops, n_ops, prec, no_neg);
t0 = get_clock();
for (i = 0; i < OPS_PER_ITER; i++) {
double a = ops[0].d;
double b = ops[1].d;
double c = ops[2].d;
switch (op) {
case OP_ADD:
res.d = a + b;
break;
case OP_SUB:
res.d = a - b;
break;
case OP_MUL:
res.d = a * b;
break;
case OP_DIV:
res.d = a / b;
break;
case OP_FMA:
res.d = fma(a, b, c);
break;
case OP_SQRT:
res.d = sqrt(a);
break;
case OP_CMP:
res.u64 = isgreater(a, b);
break;
default:
g_assert_not_reached();
}
}
break;
case PREC_FLOAT32:
fill_random(ops, n_ops, prec, no_neg);
t0 = get_clock();
for (i = 0; i < OPS_PER_ITER; i++) {
float32 a = ops[0].f32;
float32 b = ops[1].f32;
float32 c = ops[2].f32;
switch (op) {
case OP_ADD:
res.f32 = float32_add(a, b, &soft_status);
break;
case OP_SUB:
res.f32 = float32_sub(a, b, &soft_status);
break;
case OP_MUL:
res.f = float32_mul(a, b, &soft_status);
break;
case OP_DIV:
res.f32 = float32_div(a, b, &soft_status);
break;
case OP_FMA:
res.f32 = float32_muladd(a, b, c, 0, &soft_status);
break;
case OP_SQRT:
res.f32 = float32_sqrt(a, &soft_status);
break;
case OP_CMP:
res.u64 = float32_compare_quiet(a, b, &soft_status);
break;
default:
g_assert_not_reached();
}
}
break;
case PREC_FLOAT64:
fill_random(ops, n_ops, prec, no_neg);
t0 = get_clock();
for (i = 0; i < OPS_PER_ITER; i++) {
float64 a = ops[0].f64;
float64 b = ops[1].f64;
float64 c = ops[2].f64;
switch (op) {
case OP_ADD:
res.f64 = float64_add(a, b, &soft_status);
break;
case OP_SUB:
res.f64 = float64_sub(a, b, &soft_status);
break;
case OP_MUL:
res.f = float64_mul(a, b, &soft_status);
break;
case OP_DIV:
res.f64 = float64_div(a, b, &soft_status);
break;
case OP_FMA:
res.f64 = float64_muladd(a, b, c, 0, &soft_status);
break;
case OP_SQRT:
res.f64 = float64_sqrt(a, &soft_status);
break;
case OP_CMP:
res.u64 = float64_compare_quiet(a, b, &soft_status);
break;
default:
g_assert_not_reached();
}
}
break;
default:
g_assert_not_reached();
}
ns_elapsed += get_clock() - t0;
n_completed_ops += OPS_PER_ITER;
}
}
#define GEN_BENCH(name, type, prec, op, n_ops) \
static void __attribute__((flatten)) name(void) \
{ \
bench(prec, op, n_ops, false); \
}
#define GEN_BENCH_NO_NEG(name, type, prec, op, n_ops) \
static void __attribute__((flatten)) name(void) \
{ \
bench(prec, op, n_ops, true); \
}
#define GEN_BENCH_ALL_TYPES(opname, op, n_ops) \
GEN_BENCH(bench_ ## opname ## _float, float, PREC_SINGLE, op, n_ops) \
GEN_BENCH(bench_ ## opname ## _double, double, PREC_DOUBLE, op, n_ops) \
GEN_BENCH(bench_ ## opname ## _float32, float32, PREC_FLOAT32, op, n_ops) \
GEN_BENCH(bench_ ## opname ## _float64, float64, PREC_FLOAT64, op, n_ops)
GEN_BENCH_ALL_TYPES(add, OP_ADD, 2)
GEN_BENCH_ALL_TYPES(sub, OP_SUB, 2)
GEN_BENCH_ALL_TYPES(mul, OP_MUL, 2)
GEN_BENCH_ALL_TYPES(div, OP_DIV, 2)
GEN_BENCH_ALL_TYPES(fma, OP_FMA, 3)
GEN_BENCH_ALL_TYPES(cmp, OP_CMP, 2)
#undef GEN_BENCH_ALL_TYPES
#define GEN_BENCH_ALL_TYPES_NO_NEG(name, op, n) \
GEN_BENCH_NO_NEG(bench_ ## name ## _float, float, PREC_SINGLE, op, n) \
GEN_BENCH_NO_NEG(bench_ ## name ## _double, double, PREC_DOUBLE, op, n) \
GEN_BENCH_NO_NEG(bench_ ## name ## _float32, float32, PREC_FLOAT32, op, n) \
GEN_BENCH_NO_NEG(bench_ ## name ## _float64, float64, PREC_FLOAT64, op, n)
GEN_BENCH_ALL_TYPES_NO_NEG(sqrt, OP_SQRT, 1)
#undef GEN_BENCH_ALL_TYPES_NO_NEG
#undef GEN_BENCH_NO_NEG
#undef GEN_BENCH
#define GEN_BENCH_FUNCS(opname, op) \
[op] = { \
[PREC_SINGLE] = bench_ ## opname ## _float, \
[PREC_DOUBLE] = bench_ ## opname ## _double, \
[PREC_FLOAT32] = bench_ ## opname ## _float32, \
[PREC_FLOAT64] = bench_ ## opname ## _float64, \
}
static const bench_func_t bench_funcs[OP_MAX_NR][PREC_MAX_NR] = {
GEN_BENCH_FUNCS(add, OP_ADD),
GEN_BENCH_FUNCS(sub, OP_SUB),
GEN_BENCH_FUNCS(mul, OP_MUL),
GEN_BENCH_FUNCS(div, OP_DIV),
GEN_BENCH_FUNCS(fma, OP_FMA),
GEN_BENCH_FUNCS(sqrt, OP_SQRT),
GEN_BENCH_FUNCS(cmp, OP_CMP),
};
#undef GEN_BENCH_FUNCS
static void run_bench(void)
{
bench_func_t f;
f = bench_funcs[operation][precision];
g_assert(f);
f();
}
/* @arr must be NULL-terminated */
static int find_name(const char * const *arr, const char *name)
{
int i;
for (i = 0; arr[i] != NULL; i++) {
if (strcmp(name, arr[i]) == 0) {
return i;
}
}
return -1;
}
static void usage_complete(int argc, char *argv[])
{
gchar *op_list = g_strjoinv(", ", (gchar **)op_names);
gchar *tester_list = g_strjoinv(", ", (gchar **)tester_names);
fprintf(stderr, "Usage: %s [options]\n", argv[0]);
fprintf(stderr, "options:\n");
fprintf(stderr, " -d = duration, in seconds. Default: %d\n",
DEFAULT_DURATION_SECS);
fprintf(stderr, " -h = show this help message.\n");
fprintf(stderr, " -o = floating point operation (%s). Default: %s\n",
op_list, op_names[0]);
fprintf(stderr, " -p = floating point precision (single, double). "
"Default: single\n");
fprintf(stderr, " -r = rounding mode (even, zero, down, up, tieaway). "
"Default: even\n");
fprintf(stderr, " -t = tester (%s). Default: %s\n",
tester_list, tester_names[0]);
fprintf(stderr, " -z = flush inputs to zero (soft tester only). "
"Default: disabled\n");
fprintf(stderr, " -Z = flush output to zero (soft tester only). "
"Default: disabled\n");
g_free(tester_list);
g_free(op_list);
}
static int round_name_to_mode(const char *name)
{
int i;
for (i = 0; i < N_ROUND_MODES; i++) {
if (!strcmp(round_names[i], name)) {
return i;
}
}
return -1;
}
static void QEMU_NORETURN die_host_rounding(enum rounding rounding)
{
fprintf(stderr, "fatal: '%s' rounding not supported on this host\n",
round_names[rounding]);
exit(EXIT_FAILURE);
}
static void set_host_precision(enum rounding rounding)
{
int rhost;
switch (rounding) {
case ROUND_EVEN:
rhost = FE_TONEAREST;
break;
case ROUND_ZERO:
rhost = FE_TOWARDZERO;
break;
case ROUND_DOWN:
rhost = FE_DOWNWARD;
break;
case ROUND_UP:
rhost = FE_UPWARD;
break;
case ROUND_TIEAWAY:
die_host_rounding(rounding);
return;
default:
g_assert_not_reached();
}
if (fesetround(rhost)) {
die_host_rounding(rounding);
}
}
static void set_soft_precision(enum rounding rounding)
{
signed char mode;
switch (rounding) {
case ROUND_EVEN:
mode = float_round_nearest_even;
break;
case ROUND_ZERO:
mode = float_round_to_zero;
break;
case ROUND_DOWN:
mode = float_round_down;
break;
case ROUND_UP:
mode = float_round_up;
break;
case ROUND_TIEAWAY:
mode = float_round_ties_away;
break;
default:
g_assert_not_reached();
}
soft_status.float_rounding_mode = mode;
}
static void parse_args(int argc, char *argv[])
{
int c;
int val;
int rounding = ROUND_EVEN;
for (;;) {
c = getopt(argc, argv, "d:ho:p:r:t:zZ");
if (c < 0) {
break;
}
switch (c) {
case 'd':
duration = atoi(optarg);
break;
case 'h':
usage_complete(argc, argv);
exit(EXIT_SUCCESS);
case 'o':
val = find_name(op_names, optarg);
if (val < 0) {
fprintf(stderr, "Unsupported op '%s'\n", optarg);
exit(EXIT_FAILURE);
}
operation = val;
break;
case 'p':
if (!strcmp(optarg, "single")) {
precision = PREC_SINGLE;
} else if (!strcmp(optarg, "double")) {
precision = PREC_DOUBLE;
} else {
fprintf(stderr, "Unsupported precision '%s'\n", optarg);
exit(EXIT_FAILURE);
}
break;
case 'r':
rounding = round_name_to_mode(optarg);
if (rounding < 0) {
fprintf(stderr, "fatal: invalid rounding mode '%s'\n", optarg);
exit(EXIT_FAILURE);
}
break;
case 't':
val = find_name(tester_names, optarg);
if (val < 0) {
fprintf(stderr, "Unsupported tester '%s'\n", optarg);
exit(EXIT_FAILURE);
}
tester = val;
break;
case 'z':
soft_status.flush_inputs_to_zero = 1;
break;
case 'Z':
soft_status.flush_to_zero = 1;
break;
}
}
/* set precision and rounding mode based on the tester */
switch (tester) {
case TESTER_HOST:
set_host_precision(rounding);
break;
case TESTER_SOFT:
set_soft_precision(rounding);
switch (precision) {
case PREC_SINGLE:
precision = PREC_FLOAT32;
break;
case PREC_DOUBLE:
precision = PREC_FLOAT64;
break;
default:
g_assert_not_reached();
}
break;
default:
g_assert_not_reached();
}
}
static void pr_stats(void)
{
printf("%.2f MFlops\n", (double)n_completed_ops / ns_elapsed * 1e3);
}
int main(int argc, char *argv[])
{
parse_args(argc, argv);
run_bench();
pr_stats();
return 0;
}