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authorVladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>2018-03-09 19:52:11 +0300
committerEric Blake <eblake@redhat.com>2018-03-19 14:58:37 -0500
commitb741ae74170643de0fec3005c717e3a397c3e034 (patch)
treed16b50a589fb7f94c48970612b84f1bac84903d6 /include
parentd003f7a8f9cafe50119975844fa01afc2baf41fb (diff)
block/accounting: introduce latency histogram
Introduce latency histogram statics for block devices. For each accounted operation type, the latency region [0, +inf) is divided into subregions by several points. Then, calculate hits for each subregion. Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com> Message-Id: <20180309165212.97144-2-vsementsov@virtuozzo.com> Reviewed-by: Eric Blake <eblake@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Eric Blake <eblake@redhat.com>
Diffstat (limited to 'include')
-rw-r--r--include/block/accounting.h35
1 files changed, 35 insertions, 0 deletions
diff --git a/include/block/accounting.h b/include/block/accounting.h
index b833d26d6c..d1f67b10dd 100644
--- a/include/block/accounting.h
+++ b/include/block/accounting.h
@@ -27,6 +27,7 @@
#include "qemu/timed-average.h"
#include "qemu/thread.h"
+#include "qapi/qapi-builtin-types.h"
typedef struct BlockAcctTimedStats BlockAcctTimedStats;
typedef struct BlockAcctStats BlockAcctStats;
@@ -45,6 +46,36 @@ struct BlockAcctTimedStats {
QSLIST_ENTRY(BlockAcctTimedStats) entries;
};
+typedef struct BlockLatencyHistogram {
+ /* The following histogram is represented like this:
+ *
+ * 5| *
+ * 4| *
+ * 3| * *
+ * 2| * * *
+ * 1| * * * *
+ * +------------------
+ * 10 50 100
+ *
+ * BlockLatencyHistogram histogram = {
+ * .nbins = 4,
+ * .boundaries = {10, 50, 100},
+ * .bins = {3, 1, 5, 2},
+ * };
+ *
+ * @boundaries array define histogram intervals as follows:
+ * [0, boundaries[0]), [boundaries[0], boundaries[1]), ...
+ * [boundaries[nbins-2], +inf)
+ *
+ * So, for example above, histogram intervals are:
+ * [0, 10), [10, 50), [50, 100), [100, +inf)
+ */
+ int nbins;
+ uint64_t *boundaries; /* @nbins-1 numbers here
+ (all boundaries, except 0 and +inf) */
+ uint64_t *bins;
+} BlockLatencyHistogram;
+
struct BlockAcctStats {
QemuMutex lock;
uint64_t nr_bytes[BLOCK_MAX_IOTYPE];
@@ -57,6 +88,7 @@ struct BlockAcctStats {
QSLIST_HEAD(, BlockAcctTimedStats) intervals;
bool account_invalid;
bool account_failed;
+ BlockLatencyHistogram latency_histogram[BLOCK_MAX_IOTYPE];
};
typedef struct BlockAcctCookie {
@@ -82,5 +114,8 @@ void block_acct_merge_done(BlockAcctStats *stats, enum BlockAcctType type,
int64_t block_acct_idle_time_ns(BlockAcctStats *stats);
double block_acct_queue_depth(BlockAcctTimedStats *stats,
enum BlockAcctType type);
+int block_latency_histogram_set(BlockAcctStats *stats, enum BlockAcctType type,
+ uint64List *boundaries);
+void block_latency_histograms_clear(BlockAcctStats *stats);
#endif