seqreader

seqreader.c

@@ -0,0 +1,79 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/time.h>
+#include <unistd.h>
+#include <dirent.h>
+
+#define BUFSIZE 65536
+
+int main(int argc, char *argv[]) {
+    int err;
+    size_t SKIP = 1;
+    DIR *dir;
+    struct dirent *ent;
+    struct timeval start, tv;
+    size_t us;
+    size_t files = 0;
+    size_t total_size = 0;
+    size_t skip;
+    size_t run;
+    char buffer[65536];
+    
+    if (argc < 2) {
+	printf("Usage: %s <directory> [skip]\n", argv[0]);
+	exit(0);
+    }
+    
+    chdir(argv[1]);
+
+    if (argc > 2) {
+	SKIP = atoi(argv[2]);
+	
+	printf("Skip %i\n", SKIP);
+    }
+
+    gettimeofday(&start, NULL);
+    for (run = 0; run < SKIP; run++) {
+      skip = 0;
+      dir = opendir(".");
+      while (ent = readdir(dir)) {
+	struct stat st;
+	
+	if (((skip++)%SKIP) != run) continue;
+
+	if (stat(ent->d_name, &st)) continue;
+	if (!S_ISREG(st.st_mode)) continue;
+	
+	FILE *f = fopen(ent->d_name, "r");
+	if (!f) continue;
+	
+	int size = st.st_blksize;
+	
+	if (size > BUFSIZE) {
+	    printf("Buffer too small\n");
+	    exit(1);
+	}
+	
+	while (!feof(f)) {
+	    err = fread(buffer, 1, size, f);
+	    if (err < 0) {
+		printf("Read failed\n");
+		exit(1);
+	    }
+	}
+	
+	fclose(f);
+
+	total_size += st.st_size;
+	files++;
+	
+	gettimeofday(&tv, NULL);
+	us = (tv.tv_sec - start.tv_sec) * 1000000 + (tv.tv_usec - start.tv_usec);
+	printf("Reading: %s (%lu MB), Read: %lu files (%lu GB),  Measured speed: %lu mB/s\n", ent->d_name, st.st_size/1024/1024, files, total_size / 1024 / 1024 / 1024, total_size / us);
+      }
+      closedir(dir);
+    }
+
+}