performance measurements
Each table row shows performance measurements for this C gcc program with a particular command-line input value N.
| N | CPU secs | Elapsed secs | Memory KB | Code B | ≈ CPU Load |
|---|---|---|---|---|---|
| 500,000 | 0.24 | 0.25 | 368 | 1429 | 4% 0% 4% 100% |
| 5,000,000 | 2.37 | 2.38 | 372 | 1429 | 0% 1% 100% 0% |
| 50,000,000 | 23.68 | 23.69 | 372 | 1429 | 0% 0% 0% 100% |
Read the ↓ make, command line, and program output logs to see how this program was run.
Read n-body benchmark to see what this program should do.
notes
gcc (Ubuntu/Linaro 4.7.3-1ubuntu1) 4.7.3
n-body C gcc #5 program source code
/* The Computer Language Benchmarks Game * http://benchmarksgame.alioth.debian.org/ * * contributed by Christoph Bauer * slightly improved by Mark Hinds * SIMDified by Stefan Krause * translated in ANSI C by Francesco Massei */ #include <math.h> #include <stdio.h> #include <stdlib.h> #define pi 3.141592653589793 #define solar_mass (4 * pi * pi) #define days_per_year 365.24 typedef double v2df __attribute__ (( vector_size(2*sizeof(double)) )); #define lower(_V) (((double*)&_V)[0]) struct planet { v2df xy; v2df z0; /* z and zero */ v2df vxvy; v2df vz00; /* vz and zero */ v2df massmass; /* the mass in both components */ }; #define NBODIES 5 static struct planet bodies[NBODIES] = { { /* sun */ {0, 0}, {0,0}, {0, 0}, {0,0}, {solar_mass,solar_mass} }, { /* jupiter */ {4.84143144246472090e+00, -1.16032004402742839e+00}, {-1.03622044471123109e-01, 0}, {1.66007664274403694e-03 * days_per_year, 7.69901118419740425e-03 * days_per_year}, {-6.90460016972063023e-05 * days_per_year,0}, {9.54791938424326609e-04 * solar_mass,9.54791938424326609e-04 * solar_mass} }, { /* saturn */ {8.34336671824457987e+00, 4.12479856412430479e+00}, {-4.03523417114321381e-01, 0}, {-2.76742510726862411e-03 * days_per_year, 4.99852801234917238e-03 * days_per_year}, {2.30417297573763929e-05 * days_per_year,0}, {2.85885980666130812e-04 * solar_mass,2.85885980666130812e-04 * solar_mass} }, { /* uranus */ {1.28943695621391310e+01, -1.51111514016986312e+01}, {-2.23307578892655734e-01,0}, {2.96460137564761618e-03 * days_per_year, 2.37847173959480950e-03 * days_per_year}, {-2.96589568540237556e-05 * days_per_year,0}, {4.36624404335156298e-05 * solar_mass,4.36624404335156298e-05 * solar_mass} }, { /* neptune */ {1.53796971148509165e+01, -2.59193146099879641e+01}, {1.79258772950371181e-01,0}, {2.68067772490389322e-03 * days_per_year, 1.62824170038242295e-03 * days_per_year}, {-9.51592254519715870e-05 * days_per_year,0}, {5.15138902046611451e-05 * solar_mass,5.15138902046611451e-05 * solar_mass} } }; static v2df dtdt = {0.01, 0.01}; static void advance(int q) { struct planet *b, *b2; v2df dxdy, dz00, tsquare, distance2, magmag; int i, j, k; for (k=1; k<=q; ++k) { for (i = 0; i < NBODIES; ++i) { b = &(bodies[i]); for (j = i + 1; j < NBODIES; j++) { b2 = &(bodies[j]); dxdy = b->xy - b2->xy; dz00 = b->z0 - b2->z0; /* dx*dx+dy*dy | dz*dz */ tsquare = __builtin_ia32_haddpd(dxdy*dxdy,dz00*dz00); /* dx*dx+dy*dy+dz*dz | dx*dx+dy*dy+dz*dz */ distance2 = __builtin_ia32_haddpd(tsquare,tsquare); magmag = dtdt / (__builtin_ia32_sqrtpd(distance2)*distance2); dxdy *= magmag; dz00 *= magmag; b->vxvy -= dxdy * b2->massmass; b->vz00 -= dz00 * b2->massmass; b2->vxvy += dxdy * b->massmass; b2->vz00 += dz00 * b->massmass; } } for (i = 0; i < NBODIES; i++) { bodies[i].xy += dtdt * bodies[i].vxvy; bodies[i].z0 += dtdt * bodies[i].vz00; } } } static double energy() { v2df e = {0.0, 0.0}; v2df half = {0.5, 0.5}; v2df sq, dxdy, dz00, distance; struct planet *b, *b2; int i, j; for (i = 0; i < NBODIES; i++) { b = &(bodies[i]); /* b->mass*(vx*vx + vy*vy) | b->mass*(vz*vz + 0*0) */ sq = b->massmass * __builtin_ia32_haddpd(b->vxvy*b->vxvy, b->vz00*b->vz00); sq = __builtin_ia32_haddpd(sq, sq); e += half * sq; for (j = i + 1; j < NBODIES; j++) { b2 = &(bodies[j]); dxdy = b->xy - b2->xy; dz00 = b->z0 - b2->z0; /* b->mass*(vx*vx + vy*vy) | b->mass*(vz*vz + 0*0) */ distance = __builtin_ia32_haddpd(dxdy*dxdy, dz00*dz00); distance = __builtin_ia32_sqrtpd(__builtin_ia32_haddpd(distance,distance)); e -= (b->massmass * b2->massmass) / distance; } } return lower(e); } static void offset_momentum() { v2df pxpy = {0.0, 0.0}; v2df pz00 = {0.0, 0.0}; v2df solar_mass_inv = { 1.0 / solar_mass, 1.0 / solar_mass}; int i; for (i = 0; i < NBODIES; i++) { pxpy += bodies[i].vxvy * bodies[i].massmass; pz00 += bodies[i].vz00 * bodies[i].massmass; } bodies[0].vxvy = - pxpy * solar_mass_inv; bodies[0].vz00 = - pz00 * solar_mass_inv; } int main(int argc, char ** argv) { offset_momentum(); printf ("%.9f\n", energy()); advance(atoi(argv[1])); printf ("%.9f\n", energy()); return 0; }
make, command-line, and program output logs
Sat, 27 Apr 2013 04:56:24 GMT MAKE: /usr/bin/gcc -pipe -Wall -O3 -fomit-frame-pointer -march=native -mfpmath=sse -msse3 nbody.gcc-5.c -o nbody.gcc-5.gcc_run -lm rm nbody.gcc-5.c 0.12s to complete and log all make actions COMMAND LINE: ./nbody.gcc-5.gcc_run 50000000 PROGRAM OUTPUT: -0.169075164 -0.169059907