// Test-case: Benchmark pipe performance
//    Author: Linus Torvalds
//      Link: https://git.kernel.org/linus/0ddad21d3e99
//
//   Compile: gcc-12 -o 0ddad21d3e99 0ddad21d3e99.c
//
#include <unistd.h>

int main(int argc, char **argv)
    {
        int fd[2], counters[2];

        pipe(fd);
        counters[0] = 0;
        counters[1] = -1;
        write(fd[1], counters, sizeof(counters));

        /* 64 processes */
        fork(); fork(); fork(); fork(); fork(); fork();

        do {
                int i;
                read(fd[0], &i, sizeof(i));
                if (i < 0)
                        continue;
                counters[0] = i+1;
                write(fd[1], counters, (1+(i & 1)) *sizeof(int));
        } while (counters[0] < 1000000);
        return 0;
    }