add a small benchmark to quickly bench/compare SMP support

1 files changed, 43 insertions, 0 deletions

diff --git a/bench/bench_gemm.cpp b/bench/bench_gemm.cpp
new file mode 100644
index 000000000..d110a0fcd
--- /dev/null
+++ b/bench/bench_gemm.cpp
@@ -0,0 +1,43 @@
+
+// g++-4.4 bench_gemm.cpp -I .. -O2 -DNDEBUG -lrt -fopenmp && OMP_NUM_THREADS=2  ./a.out
+// icpc bench_gemm.cpp -I .. -O3 -DNDEBUG -lrt -openmp  && OMP_NUM_THREADS=2  ./a.out
+
+#include <Eigen/Core>
+#include "../../eigen2/bench/BenchTimer.h"
+
+using namespace std;
+using namespace Eigen;
+
+#ifndef SCALAR
+#define SCALAR float
+#endif
+
+typedef SCALAR Scalar;
+typedef Matrix<Scalar,Dynamic,Dynamic> M;
+
+void gemm(const M& a, const M& b, M& c)
+{
+  c.noalias() += a * b;
+}
+
+int main(int argc, char ** argv)
+{
+  int rep = 2;
+  int s = 1024;
+  int m = s;
+  int n = s;
+  int p = s;
+  M a(m,n); a.setOnes();
+  M b(n,p); b.setOnes();
+  M c(m,p); c.setOnes();
+
+  BenchTimer t;
+
+  BENCH(t, 5, rep, gemm(a,b,c));
+
+  std::cerr << "cpu   " << t.best(CPU_TIMER)/rep  << "s  \t" << (double(m)*n*p*rep*2/t.best(CPU_TIMER))*1e-9  <<  " GFLOPS \t(" << t.total(CPU_TIMER)  << "s)\n";
+  std::cerr << "real  " << t.best(REAL_TIMER)/rep << "s  \t" << (double(m)*n*p*rep*2/t.best(REAL_TIMER))*1e-9 <<  " GFLOPS \t(" << t.total(REAL_TIMER) << "s)\n";
+
+  return 0;
+}
+