X-Git-Url: http://git.vrable.net/?a=blobdiff_plain;f=microbench%2Fmixedbench.c;h=475542496862a1a5f08ff4060447988376815a4a;hb=HEAD;hp=a93d5f93cdd906abb7a4b33eef6a87ea3dfd9584;hpb=0e57b9b0865caf4b47deadbc17ef46bca4ea98d2;p=bluesky.git

diff --git a/microbench/mixedbench.c b/microbench/mixedbench.c
index a93d5f9..4755424 100644
--- a/microbench/mixedbench.c
+++ b/microbench/mixedbench.c
@@ -11,6 +11,7 @@
  *   Target operations per second (aggregate across all threads)
  *   Interval count (how many times to report results during the run)
  *   Directory size (number of files per numbered subdirectory)
+ *   Read/write block size (0 for the entire file)
  */
 
 #include <errno.h>
@@ -26,7 +27,7 @@
 #include <unistd.h>
 #include <math.h>
 
-int opt_filesize, opt_filecount, opt_threads, opt_duration, opt_intervals, opt_dirsize;
+int opt_filesize, opt_filecount, opt_threads, opt_duration, opt_intervals, opt_dirsize, opt_blocksize;
 double opt_writeratio, opt_ops;
 
 int write_threads;
@@ -111,6 +112,13 @@ void benchmark_op(struct thread_state *ts)
     char filename[256];
     sprintf(filename, "%d/%d", n1, n2);
 
+    /* If a smaller blocksize was requested, choose a random offset within the
+     * file to use. */
+    int offset = 0;
+    if (opt_blocksize > 0) {
+        offset = get_random(opt_filesize / opt_blocksize) * opt_blocksize;
+    }
+
     if (ts->thread_num >= write_threads) {
         /* Read */
         FILE *f = fopen(filename, "rb");
@@ -119,8 +127,18 @@ void benchmark_op(struct thread_state *ts)
             return;
         }
 
+        if (offset != 0)
+            fseek(f, offset, SEEK_SET);
+
         char buf[65536];
-        while (fread(buf, 1, sizeof(buf), f) > 0) { }
+        int bytes_left = opt_blocksize > 0 ? opt_blocksize : opt_filesize;
+        while (bytes_left > 0) {
+            size_t read = fread(buf, 1, bytes_left < sizeof(buf)
+                                         ? bytes_left : sizeof(buf), f);
+            if (ferror(f))
+                return;
+            bytes_left -= read;
+        }
         fclose(f);
 
         end = now_hires();
@@ -131,14 +149,17 @@ void benchmark_op(struct thread_state *ts)
         pthread_mutex_unlock(&ts->lock);
     } else {
         /* Write */
-        FILE *f = fopen(filename, "wb");
+        FILE *f = fopen(filename, "r+b");
         if (f == NULL) {
             fprintf(stderr, "fopen(%s): %m\n", filename);
             return;
         }
 
+        if (offset != 0)
+            fseek(f, offset, SEEK_SET);
+
         char buf[65536];
-        int bytes_left = opt_filesize;
+        int bytes_left = opt_blocksize > 0 ? opt_blocksize : opt_filesize;
         while (bytes_left > 0) {
             size_t written = fwrite(buf, 1,
                                     bytes_left < sizeof(buf)
@@ -228,7 +249,7 @@ void reset_stats(int print, double duration)
 
 int main(int argc, char *argv[])
 {
-    if (argc != 9) {
+    if (argc != 10) {
         fprintf(stderr, "Usage: TODO\n");
         return 1;
     }
@@ -241,6 +262,7 @@ int main(int argc, char *argv[])
     opt_ops = atof(argv[6]);
     opt_intervals = atoi(argv[7]);
     opt_dirsize = atoi(argv[8]);
+    opt_blocksize = atoi(argv[9]);
 
     srandom(time(NULL));