Only log the period mean if we have samples

We can't use the mean value to determine that, it could in theory
be 0.0 and still have valid samples.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/stat.c b/stat.c
index 7de2362132d9deae23017169c3d07f10389f4a5f..c921f5f4379187e5affa6622f360f489b8fce92d 100644 (file)
--- a/stat.c
+++ b/stat.c
@@ -1145,11 +1145,17 @@ static void __add_log_sample(struct io_log *iolog, unsigned long val,
        iolog->nr_samples++;
 }
 
+static inline void reset_io_stat(struct io_stat *ios)
+{
+       ios->max_val = ios->min_val = ios->samples = 0;
+       ios->mean.u.f = ios->S.u.f = 0;
+}
+
 static void add_log_sample(struct thread_data *td, struct io_log *iolog,
                           unsigned long val, enum fio_ddir ddir,
                           unsigned int bs)
 {
-       unsigned long elapsed, this_window, mr, mw;
+       unsigned long elapsed, this_window;
 
        if (!ddir_rw(ddir))
                return;
@@ -1170,20 +1176,34 @@ static void add_log_sample(struct thread_data *td, struct io_log *iolog,
         */
        add_stat_sample(&iolog->avg_window[ddir], val);
 
+       /*
+        * If period hasn't passed, adding the above sample is all we
+        * need to do.
+        */
        this_window = elapsed - iolog->avg_last;
        if (this_window < iolog->avg_msec)
                return;
 
-       mr = iolog->avg_window[DDIR_READ].mean.u.f;
-       mw = iolog->avg_window[DDIR_WRITE].mean.u.f;
+       /*
+        * Note an entry in the log. Use the mean from the logged samples,
+        * making sure to properly round up. Only write a log entry if we
+        * had actual samples done.
+        */
+       if (iolog->avg_window[DDIR_READ].samples) {
+               unsigned long mr;
 
-       if (mr)
+               mr = iolog->avg_window[DDIR_READ].mean.u.f + 0.50;
                __add_log_sample(iolog, mr, DDIR_READ, 0, elapsed);
-       if (mw)
+       }
+       if (iolog->avg_window[DDIR_WRITE].samples) {
+               unsigned long mw;
+
+               mw = iolog->avg_window[DDIR_WRITE].mean.u.f + 0.50;
                __add_log_sample(iolog, mw, DDIR_WRITE, 0, elapsed);
+       }
 
-       memset(&iolog->avg_window[DDIR_READ], 0, sizeof(struct io_stat));
-       memset(&iolog->avg_window[DDIR_WRITE], 0, sizeof(struct io_stat));
+       reset_io_stat(&iolog->avg_window[DDIR_READ]);
+       reset_io_stat(&iolog->avg_window[DDIR_WRITE]);
        iolog->avg_last = elapsed;
 }