Writing kernel modules in Haskell

Writing kernel modules in Haskell

Posted Sep 15, 2009 10:35 UTC (Tue) by sagrailo (guest, #48054)
In reply to: Writing kernel modules in Haskell by Ed_L.
Parent article: Writing kernel modules in Haskell

Yeah, right... I just quickly wrote this code (to multiply two matrices):

#include <algorithm>
#include <cassert>
#include <cstdlib>
#include <ctime>
#include <iostream>

extern "C" {
#include <cblas.h>
}

#include <tnt.h>

#define N 1024

int
main(void)
{
    float* A = new float[N * N];
    float* B = new float[N * N];
    float* C = new float[N * N];
    std::fill(C, C + N * N, 0);

    TNT::Array2D<float< ATNT(N, N);
    TNT::Array2D<float< BTNT(N, N);
    TNT::Array2D<float< CTNT(N, N);

    for (int i = 0; i < N; ++i)
        for (int j = 0; j < N; ++j) {
            A[i * N + j] = ATNT[i][j] = 1;
            B[i * N + j] = BTNT[i][j] = 1;
        }

    clock_t start, end;

    start = clock();
    cblas_sgemm(CblasRowMajor, CblasNoTrans, CblasNoTrans, N, N, N, 1, A, N, B,
                N, 0, C, N);
    end = clock();
    std::cerr
        << "ATLAS: "
        << (float) (end - start) / CLOCKS_PER_SEC
        << "s"
        << std::endl;

    start = clock();
    CTNT = TNT::matmult(ATNT, BTNT);
    end = clock();
    std::cerr
        << "TNT:   "
        << (float) (end - start) / CLOCKS_PER_SEC
        << "s"
        << std::endl;

    for (int i = 0; i < N; ++i)
        for (int j = 0; j < N; ++j) {
            assert(C[i * N + j] == N);
	    assert(CTNT[i][j] == N);
        }

    delete [] A;
    delete [] B;
    delete [] C;
}

Complied with (I've put TNT into /tmp, and I have ATLAS installed in /usr/local):

g++ -O3 -o foo -I/tmp/tnt foo.cpp -lcblas -latlas

The output, on my old ThinkPad T61p:

ATLAS: 0.22s
TNT:   17.64s

So - C++ almost two orders of magnitude slower (and that's typical, in my experience).

---

(Log in to post comments)