[PATCH 4/4] stats: Add hint information to per priority level stats

[Damien Le Moal <dlemoal@kernel.org>]

From: Damien Le Moal <damien.lemoal@opensource.wdc.com>

Introduce the OS dependent ioprio_hint() macro to extract an IO
priority hint from an ioprio value. This macro defaults to always
returning 0 for OSes that do not support IO priority hints.

The json and standard output stats are modified to display the hint
value together with the priority class and level.

Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
---
 os/os-linux.h |  4 ++++
 os/os.h       |  3 +++
 stat.c        | 10 +++++++---
 3 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/os/os-linux.h b/os/os-linux.h
index 6f241d09..b9c07891 100644
--- a/os/os-linux.h
+++ b/os/os-linux.h
@@ -150,6 +150,10 @@ static inline int ioprio_value(int ioprio_class, int ioprio, int ioprio_hint)
 		ioprio;
 }
 
+#define ioprio_class(ioprio)	((ioprio) >> IOPRIO_CLASS_SHIFT)
+#define ioprio_hint(ioprio)	(((ioprio) >> IOPRIO_HINT_SHIFT) & 0x3ff)
+#define ioprio(ioprio)		((ioprio) & 7)
+
 static inline bool ioprio_value_is_class_rt(unsigned int priority)
 {
 	return (priority >> IOPRIO_CLASS_SHIFT) == IOPRIO_CLASS_RT;
diff --git a/os/os.h b/os/os.h
index 2217d5f8..0f182324 100644
--- a/os/os.h
+++ b/os/os.h
@@ -120,6 +120,9 @@ extern int fio_cpus_split(os_cpu_mask_t *mask, unsigned int cpu);
 #define ioprio_value_is_class_rt(prio)	(false)
 #define IOPRIO_MIN_PRIO_CLASS		0
 #define IOPRIO_MAX_PRIO_CLASS		0
+#define ioprio_hint(prio)		0
+#define IOPRIO_MIN_PRIO_HINT		0
+#define IOPRIO_MAX_PRIO_HINT		0
 #endif
 #ifndef FIO_HAVE_IOPRIO
 #define ioprio_value(prioclass, prio, priohint)	(0)
diff --git a/stat.c b/stat.c
index 015b8e28..4f943602 100644
--- a/stat.c
+++ b/stat.c
@@ -597,10 +597,11 @@ static void show_ddir_status(struct group_run_stats *rs, struct thread_stat *ts,
 				continue;
 
 			snprintf(buf, sizeof(buf),
-				 "%s prio %u/%u",
+				 "%s prio %u/%u/%u",
 				 clat_type,
 				 ioprio_class(ts->clat_prio[ddir][i].ioprio),
-				 ioprio(ts->clat_prio[ddir][i].ioprio));
+				 ioprio(ts->clat_prio[ddir][i].ioprio),
+				 ioprio_hint(ts->clat_prio[ddir][i].ioprio));
 			display_lat(buf, min, max, mean, dev, out);
 		}
 	}
@@ -640,10 +641,11 @@ static void show_ddir_status(struct group_run_stats *rs, struct thread_stat *ts,
 					continue;
 
 				snprintf(prio_name, sizeof(prio_name),
-					 "%s prio %u/%u (%.2f%% of IOs)",
+					 "%s prio %u/%u/%u (%.2f%% of IOs)",
 					 clat_type,
 					 ioprio_class(ts->clat_prio[ddir][i].ioprio),
 					 ioprio(ts->clat_prio[ddir][i].ioprio),
+					 ioprio_hint(ts->clat_prio[ddir][i].ioprio),
 					 100. * (double) prio_samples / (double) samples);
 				show_clat_percentiles(ts->clat_prio[ddir][i].io_u_plat,
 						prio_samples, ts->percentile_list,
@@ -1522,6 +1524,8 @@ static void add_ddir_status_json(struct thread_stat *ts,
 				ioprio_class(ts->clat_prio[ddir][i].ioprio));
 			json_object_add_value_int(obj, "prio",
 				ioprio(ts->clat_prio[ddir][i].ioprio));
+			json_object_add_value_int(obj, "priohint",
+				ioprio_hint(ts->clat_prio[ddir][i].ioprio));
 
 			tmp_object = add_ddir_lat_json(ts,
 					ts->clat_percentiles | ts->lat_percentiles,
-- 
2.41.0