Make histogram samples non-cumulative by tracking a linked-list

[fio.git] / stat.c

diff --git a/stat.c b/stat.c
index d6787b7f10973c9c3797b724736ee5fcab158706..b0ce54d98eee2938308a268418ab65e02bf5eca1 100644 (file)
--- a/stat.c
+++ b/stat.c
@@ -1965,6 +1965,7 @@ void regrow_logs(struct thread_data *td)
 {
        regrow_log(td->slat_log);
        regrow_log(td->clat_log);
+       regrow_log(td->clat_hist_log);
        regrow_log(td->lat_log);
        regrow_log(td->bw_log);
        regrow_log(td->iops_log);
@@ -2195,7 +2196,9 @@ static void add_clat_percentile_sample(struct thread_stat *ts,
 void add_clat_sample(struct thread_data *td, enum fio_ddir ddir,
                     unsigned long usec, unsigned int bs, uint64_t offset)
 {
+       unsigned long elapsed, this_window;
        struct thread_stat *ts = &td->ts;
+       struct io_log *iolog = td->clat_hist_log;
 
        td_io_u_lock(td);
 
@@ -2207,6 +2210,44 @@ void add_clat_sample(struct thread_data *td, enum fio_ddir ddir,
        if (ts->clat_percentiles)
                add_clat_percentile_sample(ts, usec, ddir);
 
+       if (iolog && iolog->hist_msec) {
+               struct io_hist *hw = &iolog->hist_window[ddir];
+
+               hw->samples++;
+               elapsed = mtime_since_now(&td->epoch);
+               if (!hw->hist_last)
+                       hw->hist_last = elapsed;
+               this_window = elapsed - hw->hist_last;
+               
+               if (this_window >= iolog->hist_msec) {
+                       unsigned int *io_u_plat;
+                       struct io_u_plat_entry *dst;
+
+                       /*
+                        * Make a byte-for-byte copy of the latency histogram
+                        * stored in td->ts.io_u_plat[ddir], recording it in a
+                        * log sample. Note that the matching call to free() is
+                        * located in iolog.c after printing this sample to the
+                        * log file.
+                        */
+                       io_u_plat = (unsigned int *) td->ts.io_u_plat[ddir];
+                       dst = malloc(sizeof(struct io_u_plat_entry));
+                       memcpy(&(dst->io_u_plat), io_u_plat,
+                               FIO_IO_U_PLAT_NR * sizeof(unsigned int));
+                       flist_add(&dst->list, &hw->list.list);
+                       __add_log_sample(iolog, (unsigned long)dst, ddir, bs,
+                                               elapsed, offset);
+
+                       /*
+                        * Update the last time we recorded as being now, minus
+                        * any drift in time we encountered before actually
+                        * making the record.
+                        */
+                       hw->hist_last = elapsed - (this_window - iolog->hist_msec);
+                       hw->samples = 0;
+               }
+       }
+
        td_io_u_unlock(td);
 }