bcache: add writeback_rate_debug stats (prometheus#1658)

* bcache: add writeback_rate_debug export

Signed-off-by: Aleksei Zakharov <zaharov@selectel.ru>

Author: AlexZzz

collector/bcache_linux.go

@@ -234,6 +234,46 @@ func (c *bcacheCollector) updateBcacheStats(ch chan<- prometheus.Metric, s *bcac
 				extraLabel:      []string{"backing_device"},
 				extraLabelValue: bdev.Name,
 			},
+			{
+				name:            "dirty_target_bytes",
+				desc:            "Current dirty data target threshold for this backing device in bytes.",
+				value:           float64(bdev.WritebackRateDebug.Target),
+				metricType:      prometheus.GaugeValue,
+				extraLabel:      []string{"backing_device"},
+				extraLabelValue: bdev.Name,
+			},
+			{
+				name:            "writeback_rate",
+				desc:            "Current writeback rate for this backing device in bytes.",
+				value:           float64(bdev.WritebackRateDebug.Rate),
+				metricType:      prometheus.GaugeValue,
+				extraLabel:      []string{"backing_device"},
+				extraLabelValue: bdev.Name,
+			},
+			{
+				name:            "writeback_rate_proportinal_term",
+				desc:            "Current result of proportional controller, part of writeback rate",
+				value:           float64(bdev.WritebackRateDebug.Proportional),
+				metricType:      prometheus.GaugeValue,
+				extraLabel:      []string{"backing_device"},
+				extraLabelValue: bdev.Name,
+			},
+			{
+				name:            "writeback_rate_integral_term",
+				desc:            "Current result of integral controller, part of writeback rate",
+				value:           float64(bdev.WritebackRateDebug.Integral),
+				metricType:      prometheus.GaugeValue,
+				extraLabel:      []string{"backing_device"},
+				extraLabelValue: bdev.Name,
+			},
+			{
+				name:            "writeback_change",
+				desc:            "Last writeback rate change step for this backing device.",
+				value:           float64(bdev.WritebackRateDebug.Change),
+				metricType:      prometheus.GaugeValue,
+				extraLabel:      []string{"backing_device"},
+				extraLabelValue: bdev.Name,
+			},
 		}
 		allMetrics = append(allMetrics, metrics...)
 

collector/fixtures/e2e-output.txt

@@ -106,6 +106,9 @@ node_bcache_congested{uuid="deaddd54-c735-46d5-868e-f331c5fd7c74"} 0
 # HELP node_bcache_dirty_data_bytes Amount of dirty data for this backing device in the cache.
 # TYPE node_bcache_dirty_data_bytes gauge
 node_bcache_dirty_data_bytes{backing_device="bdev0",uuid="deaddd54-c735-46d5-868e-f331c5fd7c74"} 0
+# HELP node_bcache_dirty_target_bytes Current dirty data target threshold for this backing device in bytes.
+# TYPE node_bcache_dirty_target_bytes gauge
+node_bcache_dirty_target_bytes{backing_device="bdev0",uuid="deaddd54-c735-46d5-868e-f331c5fd7c74"} 2.189426688e+10
 # HELP node_bcache_io_errors Number of errors that have occurred, decayed by io_error_halflife.
 # TYPE node_bcache_io_errors gauge
 node_bcache_io_errors{cache_device="cache0",uuid="deaddd54-c735-46d5-868e-f331c5fd7c74"} 0
@@ -124,6 +127,18 @@ node_bcache_root_usage_percent{uuid="deaddd54-c735-46d5-868e-f331c5fd7c74"} 0
 # HELP node_bcache_tree_depth Depth of the btree.
 # TYPE node_bcache_tree_depth gauge
 node_bcache_tree_depth{uuid="deaddd54-c735-46d5-868e-f331c5fd7c74"} 0
+# HELP node_bcache_writeback_change Last writeback rate change step for this backing device.
+# TYPE node_bcache_writeback_change gauge
+node_bcache_writeback_change{backing_device="bdev0",uuid="deaddd54-c735-46d5-868e-f331c5fd7c74"} 329204
+# HELP node_bcache_writeback_rate Current writeback rate for this backing device in bytes.
+# TYPE node_bcache_writeback_rate gauge
+node_bcache_writeback_rate{backing_device="bdev0",uuid="deaddd54-c735-46d5-868e-f331c5fd7c74"} 1.150976e+06
+# HELP node_bcache_writeback_rate_integral_term Current result of integral controller, part of writeback rate
+# TYPE node_bcache_writeback_rate_integral_term gauge
+node_bcache_writeback_rate_integral_term{backing_device="bdev0",uuid="deaddd54-c735-46d5-868e-f331c5fd7c74"} 808960
+# HELP node_bcache_writeback_rate_proportinal_term Current result of proportional controller, part of writeback rate
+# TYPE node_bcache_writeback_rate_proportinal_term gauge
+node_bcache_writeback_rate_proportinal_term{backing_device="bdev0",uuid="deaddd54-c735-46d5-868e-f331c5fd7c74"} 437748
 # HELP node_bcache_written_bytes_total Sum of all data that has been written to the cache.
 # TYPE node_bcache_written_bytes_total counter
 node_bcache_written_bytes_total{cache_device="cache0",uuid="deaddd54-c735-46d5-868e-f331c5fd7c74"} 0