if (ftruncate (ofd, size) == -1)
error (EXIT_FAILURE, errno, "ftruncate: %s", outputfile);
+ /* Tell the kernel we won't read the output file. */
+ posix_fadvise (fd, 0, 0, POSIX_FADV_RANDOM|POSIX_FADV_DONTNEED);
+
/* Iterate over blocks. */
iter_blocks (idx, nr_threads, filename, fd, outputfile, ofd);