94 lines
2.9 KiB
C
94 lines
2.9 KiB
C
#include <sys/syscall.h>
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#include <sys/time.h>
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#include <sys/wait.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <spawn.h>
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#include <string.h>
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#define KB (1024UL)
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#define MB (1024UL * 1024UL)
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#define GB (1024UL * 1024UL * 1024UL)
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#define TOTAL_BYTES (2 * GB)
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#define BUF_SIZE (128 * KB)
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#define MIN(x, y) ((x) <= (y) ? (x) : (y))
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int main(int argc, const char *argv[]) {
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// Create pipe
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int pipe_fds[2];
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if (pipe(pipe_fds) < 0) {
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printf("ERROR: failed to create a pipe\n");
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return -1;
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}
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int pipe_rd_fd = pipe_fds[0];
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int pipe_wr_fd = pipe_fds[1];
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// Spawn a child process that reads from the pipe
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posix_spawn_file_actions_t file_actions;
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posix_spawn_file_actions_init(&file_actions);
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posix_spawn_file_actions_adddup2(&file_actions, pipe_rd_fd, STDIN_FILENO);
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posix_spawn_file_actions_addclose(&file_actions, pipe_wr_fd);
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int child_pid;
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if (posix_spawn(&child_pid, "/bin/data_sink", &file_actions,
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NULL, NULL, NULL) < 0) {
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printf("ERROR: failed to spawn a child process\n");
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return -1;
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}
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close(pipe_rd_fd);
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// Start the timer
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struct timeval tv_start, tv_end;
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gettimeofday(&tv_start, NULL);
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// Tell the reader how many data are to be transfered
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size_t remain_bytes = TOTAL_BYTES;
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if (write(pipe_wr_fd, &remain_bytes, sizeof(remain_bytes)) != sizeof(remain_bytes)) {
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printf("ERROR: failed to write to pipe\n");
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return -1;
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}
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// Tell the reader the buffer size that it should use
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size_t buf_size = BUF_SIZE;
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if (write(pipe_wr_fd, &buf_size, sizeof(buf_size)) != sizeof(buf_size)) {
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printf("ERROR: failed to write to pipe\n");
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return -1;
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}
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// Write a specified amount of data in a buffer of specified size
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char buf[BUF_SIZE] = {0};
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while (remain_bytes > 0) {
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size_t len = MIN(buf_size, remain_bytes);
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if ((len = write(pipe_wr_fd, &buf, len)) < 0) {
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printf("ERROR: failed to write to pipe\n");
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return -1;
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}
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remain_bytes -= len;
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}
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// Wait for the child process to read all data and exit
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int status = 0;
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if (wait4(child_pid, &status, 0, NULL) < 0) {
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printf("ERROR: failed to wait4 the child process\n");
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return -1;
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}
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// Stop the timer
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gettimeofday(&tv_end, NULL);
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// Calculate the throughput
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double total_s = (tv_end.tv_sec - tv_start.tv_sec)
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+ (double)(tv_end.tv_usec - tv_start.tv_usec) / 1000000;
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if (total_s < 1.0) {
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printf("WARNING: run long enough to get meaningful results\n");
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if (total_s == 0) { return 0; }
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}
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double total_mb = (double)TOTAL_BYTES / MB;
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double throughput = total_mb / total_s;
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printf("Throughput of pipe is %.2f MB/s\n", throughput);
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return 0;
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}
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