source: benchmark/io/readv-posix.c @ be36ec3

#include <assert.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>

extern "C" {
        #include <locale.h>
        #include <getopt.h>
        #include <fcntl.h>
        #include <sys/uio.h>
}

#include <unistd.h>

#include <pthread.h>

#include "../benchcltr.hfa"

int fd;
volatile bool run = false;
volatile size_t count = 0;

unsigned long int buflen = 50;

void * reader_main( void * arg ) {
      pthread_barrier_wait( (pthread_barrier_t*) arg );
        /* paranoid */ assert( true == __atomic_load_n(&run, __ATOMIC_RELAXED) );

        char data[buflen];
        struct iovec iov = { data, buflen };

        while(__atomic_load_n(&run, __ATOMIC_RELAXED)) {
                int r = preadv2(fd, &iov, 1, 0, 0);
                if(r < 0) {
                  fprintf(stderr, "%s\n", strerror(-r));
                  abort();
            }

                __atomic_fetch_add( &count, 1, __ATOMIC_SEQ_CST );
        }

      return NULL;
}

int main(int argc, char * argv[]) {
        BENCH_DECL
        unsigned flags = 0;
        unsigned sublen = 16;

      setlocale(LC_ALL, "");

        for(;;) {
                static struct option options[] = {
                        BENCH_OPT_LONG
                        {"polled-io",    required_argument, 0, 'i'},
                        {"bufsize",      required_argument, 0, 'b'},
                        {0, 0, 0, 0}
                };

                int idx = 0;
                int opt = getopt_long(argc, argv, BENCH_OPT_SHORT "ib:", options, &idx);

                const char * arg = optarg ? optarg : "";
                char * end;
                switch(opt) {
                        // Exit Case
                        case -1:
                                goto arg_loop;
                        BENCH_OPT_CASE
                        case 'i':
                                flags |= O_DIRECT;
                                break;
                        case 'b':
                                buflen = strtoul(arg, &end, 10);
                                if(*end != '\0' && buflen < 10) {
                                        fprintf(stderr, "Buffer size must be at least 10, was %s\n", arg);
                                        goto usage;
                                }
                                break;
                        default: /* ? */
                                fprintf(stderr, "%d\n", opt);
                        usage:
                                bench_usage( argv );
                                fprintf( stderr, "  -i, --polled-io          If set opens the file with O_DIRECT\n" );
                                fprintf( stderr, "  -b, --buflen=SIZE        Number of bytes to read per request\n" );
                                exit(EXIT_FAILURE);
                }
        }
      arg_loop:

        fd = open(__FILE__, flags);
        if(fd < 0) {
                fprintf(stderr, "Could not open source file\n");
                exit(EXIT_FAILURE);
        }

        printf("Running %d threads, reading %lu bytes each, over %d processors for %f seconds\n", nthreads, buflen, nprocs, duration);

        {
                uint64_t start, end;
                {
                        pthread_barrier_t barrier;
                  pthread_barrier_init(&barrier, NULL, nthreads + 1);
                        {
                                pthread_t threads[nthreads];
                        for(int i = 0; i < nthreads; i++) {
                                pthread_attr_t attr;
                              pthread_attr_init( &attr );
                              pthread_create( &threads[i], &attr, reader_main, &barrier );
                        }

                                printf("Starting\n");
                                bool is_tty = isatty(STDOUT_FILENO);
                                start = getTimeNsec();
                                run = true;

                                pthread_barrier_wait( &barrier );
                                wait_duration(duration, start, end, is_tty);

                                run = false;
                                end = getTimeNsec();
                                printf("\nDone\n");

                        for(int i = 0; i < nthreads; i++) {
                              void * ret;
                              pthread_join( threads[i], &ret );
                        }
                        }
                  pthread_barrier_destroy(&barrier);
                }
                printf("Took %'ld ms\n", to_miliseconds(end - start));
                printf("Total reads      : %'15zu\n", count);
                printf("Reads per second : %'18.2lf\n", ((double)count) / to_fseconds(end - start));
                printf("Total read size  : %'15zu\n", buflen * count);
                printf("Bytes per second : %'18.2lf\n", ((double)count * buflen) / to_fseconds(end - start));
        }

        close(fd);
}