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// -*-C++-*-
#define NDEBUG
#define restrict __restrict__
#include "vecmathlib.h"
#include <cassert>
#include <cstdlib>
#include <iostream>
#include <vector>
#include <sys/time.h>
using namespace std;
using namespace vecmathlib;
typedef unsigned long long ticks;
inline ticks getticks()
{
ticks a, d;
asm volatile("rdtsc" : "=a" (a), "=d" (d));
return a | (d << 32);
}
inline double elapsed(ticks t1, ticks t0)
{
return t1-t0;
}
double get_sys_time()
{
timeval tp;
gettimeofday(&tp, NULL);
return tp.tv_sec + 1.0e-6 * tp.tv_usec;
}
double measure_tick()
{
ticks const rstart = getticks();
double const wstart = get_sys_time();
while (get_sys_time() - wstart < 0.1) {
// do nothing, just wait
}
ticks const rend = getticks();
double const wend = get_sys_time();
assert(wend-wstart >= 0.09);
return (wend - wstart) / elapsed(rend, rstart);
}
template<typename realvec_t>
void init(typename realvec_t::real_t *restrict xptr,
ptrdiff_t m, ptrdiff_t ldm, ptrdiff_t n)
{
typedef typename realvec_t::real_t real_t;
for (ptrdiff_t j=0; j<n; ++j) {
for (ptrdiff_t i=0; i<m; ++i) {
const ptrdiff_t ij = ldm*j + i;
xptr[ij] = (i+j)%2;
}
}
}
// Original version, unvectorized
template<typename realvec_t>
void smootho(typename realvec_t::real_t const *restrict xptr,
typename realvec_t::real_t *restrict yptr,
ptrdiff_t m, ptrdiff_t ldm, ptrdiff_t n)
{
typedef typename realvec_t::real_t real_t;
for (ptrdiff_t j=1; j<n-1; ++j) {
for (ptrdiff_t i=1; i<m-1; ++i) {
const ptrdiff_t ij = ldm*j + i;
const real_t x = xptr[ij];
const real_t xil = xptr[ij-1];
const real_t xir = xptr[ij+1];
const real_t xjl = xptr[ij-ldm];
const real_t xjr = xptr[ij+ldm];
const real_t y =
real_t(0.5) * x + real_t(0.125) * (xil + xir + xjl + xjr);
yptr[ij] = y;
}
}
}
// Assuming that xptr and yptr are aligned, but ldm can be arbitrary
template<typename realvec_t>
void smoothu(typename realvec_t::real_t const *restrict xptr,
typename realvec_t::real_t *restrict yptr,
ptrdiff_t m, ptrdiff_t ldm, ptrdiff_t n)
{
typedef typename realvec_t::real_t real_t;
typedef typename realvec_t::mask_t mask_t;
for (ptrdiff_t j=1; j<n-1; ++j) {
// Desired loop bounds
const ptrdiff_t imin = 1;
const ptrdiff_t imax = m-1;
// Align actual loop iterations with vector size
const ptrdiff_t ioff = ldm*j;
for (mask_t mask(imin, imax, ioff); mask; ++mask) {
const ptrdiff_t i = mask.index();
const ptrdiff_t ij = ioff + i;
const realvec_t x = realvec_t::loada(xptr+ij);
const realvec_t xil = realvec_t::loadu(xptr+ij, -1);
const realvec_t xir = realvec_t::loadu(xptr+ij, +1);
const realvec_t xjl = realvec_t::loadu(xptr+ij-ldm);
const realvec_t xjr = realvec_t::loadu(xptr+ij+ldm);
const realvec_t y =
realvec_t(real_t(0.5)) * x +
realvec_t(real_t(0.125)) * (xil + xir + xjl + xjr);
y.storea(yptr+ij, mask);
}
}
}
// Assuming that xptr and yptr are aligned, and ldm is a multiple of
// the vector size
template<typename realvec_t>
void smootha(typename realvec_t::real_t const *restrict xptr,
typename realvec_t::real_t *restrict yptr,
ptrdiff_t m, ptrdiff_t ldm, ptrdiff_t n)
{
typedef typename realvec_t::real_t real_t;
typedef typename realvec_t::mask_t mask_t;
assert(ldm % realvec_t::size == 0);
for (ptrdiff_t j=1; j<n-1; ++j) {
// Desired loop bounds
const ptrdiff_t imin = 1;
const ptrdiff_t imax = m-1;
// Align actual loop iterations with vector size
const ptrdiff_t ioff = ldm*j;
for (mask_t mask(imin, imax, ioff); mask; ++mask) {
const ptrdiff_t i = mask.index();
const ptrdiff_t ij = ioff + i;
const realvec_t x = realvec_t::loada(xptr+ij);
const realvec_t xil = realvec_t::loadu(xptr+ij, -1);
const realvec_t xir = realvec_t::loadu(xptr+ij, +1);
const realvec_t xjl = realvec_t::loada(xptr+ij-ldm);
const realvec_t xjr = realvec_t::loada(xptr+ij+ldm);
const realvec_t y =
realvec_t(real_t(0.5)) * x +
realvec_t(real_t(0.125)) * (xil + xir + xjl + xjr);
y.storea(yptr+ij, mask);
}
}
}
static size_t align_up(size_t i, size_t size)
{
return (i + size - 1) / size * size;
}
int main(int argc, char** argv)
{
const int niters = 100;
const ptrdiff_t m = 1000;
const ptrdiff_t n = 1000;
#if defined VECMATHLIB_HAVE_VEC_DOUBLE_4
typedef realvec<double,4> realvec_t;
#elif defined VECMATHLIB_HAVE_VEC_DOUBLE_2
typedef realvec<double,2> realvec_t;
#else
typedef realpseudovec<double,1> realvec_t;
#endif
const ptrdiff_t ldm = align_up(m, realvec_t::size);
typedef realvec_t::real_t real_t;
vector<real_t> x(ldm*n), y(ldm*n, 0.0);
init<realvec_t>(&x[0], m, ldm, n);
ticks t0, t1;
double const cycles_per_tick = 1.0; // measure_tick();
double cycles;
t0 = getticks();
for (int iter=0; iter<niters; ++iter) {
smootho<realvec_t>(&x[0], &y[0], m, ldm, n);
}
t1 = getticks();
cycles = cycles_per_tick * elapsed(t1,t0) / (1.0 * (n-1) * (m-1) * niters);
cout << "smootho: " << cycles << " cycles/point\n";
t0 = getticks();
for (int iter=0; iter<niters; ++iter) {
smoothu<realvec_t>(&x[0], &y[0], m, ldm, n);
}
t1 = getticks();
cycles = cycles_per_tick * elapsed(t1,t0) / (1.0 * (n-1) * (m-1) * niters);
cout << "smoothu: " << cycles << " cycles/point\n";
t0 = getticks();
for (int iter=0; iter<niters; ++iter) {
smootha<realvec_t>(&x[0], &y[0], m, ldm, n);
}
t1 = getticks();
cycles = cycles_per_tick * elapsed(t1,t0) / (1.0 * (n-1) * (m-1) * niters);
cout << "smootha: " << cycles << " cycles/point\n";
return 0;
}
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