commit c488c7f649106d09df76f697adccbe6e72520b26
author Christoph Hellwig <hch@lst.de> Thu Aug 25 08:26:10 2011 +0200
committer Kevin Wolf <kwolf@redhat.com> Fri Aug 26 18:18:38 2011 +0200
tree 7933f6f000b5ea1e5cc4bf528106f85575885723
parent a597e79ce14ea62266924acc7b8a7030a42ed29b

block: latency accounting

Account the total latency for read/write/flush requests.  This allows
management tools to average it based on a snapshot of the nr ops
counters and allow checking for SLAs or provide statistics.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

block.c

diff --git a/block.c b/block.c
index 24fba37..03a21d8 100644
--- a/block.c
+++ b/block.c
@@ -1916,12 +1916,18 @@
                         " rd_operations=%" PRId64
                         " wr_operations=%" PRId64
                         " flush_operations=%" PRId64
+                        " wr_total_time_ns=%" PRId64
+                        " rd_total_time_ns=%" PRId64
+                        " flush_total_time_ns=%" PRId64
                         "\n",
                         qdict_get_int(qdict, "rd_bytes"),
                         qdict_get_int(qdict, "wr_bytes"),
                         qdict_get_int(qdict, "rd_operations"),
                         qdict_get_int(qdict, "wr_operations"),
-                        qdict_get_int(qdict, "flush_operations"));
+                        qdict_get_int(qdict, "flush_operations"),
+                        qdict_get_int(qdict, "wr_total_time_ns"),
+                        qdict_get_int(qdict, "rd_total_time_ns"),
+                        qdict_get_int(qdict, "flush_total_time_ns"));
 }
 
 void bdrv_stats_print(Monitor *mon, const QObject *data)
@@ -1940,7 +1946,10 @@
                              "'rd_operations': %" PRId64 ","
                              "'wr_operations': %" PRId64 ","
                              "'wr_highest_offset': %" PRId64 ","
-                             "'flush_operations': %" PRId64
+                             "'flush_operations': %" PRId64 ","
+                             "'wr_total_time_ns': %" PRId64 ","
+                             "'rd_total_time_ns': %" PRId64 ","
+                             "'flush_total_time_ns': %" PRId64
                              "} }",
                              bs->nr_bytes[BDRV_ACCT_READ],
                              bs->nr_bytes[BDRV_ACCT_WRITE],
@@ -1948,7 +1957,10 @@
                              bs->nr_ops[BDRV_ACCT_WRITE],
                              bs->wr_highest_sector *
                              (uint64_t)BDRV_SECTOR_SIZE,
-                             bs->nr_ops[BDRV_ACCT_FLUSH]);
+                             bs->nr_ops[BDRV_ACCT_FLUSH],
+                             bs->total_time_ns[BDRV_ACCT_WRITE],
+                             bs->total_time_ns[BDRV_ACCT_READ],
+                             bs->total_time_ns[BDRV_ACCT_FLUSH]);
     dict  = qobject_to_qdict(res);
 
     if (*bs->device_name) {
@@ -3160,6 +3172,7 @@
     assert(type < BDRV_MAX_IOTYPE);
 
     cookie->bytes = bytes;
+    cookie->start_time_ns = get_clock();
     cookie->type = type;
 }
 
@@ -3170,6 +3183,7 @@
 
     bs->nr_bytes[cookie->type] += cookie->bytes;
     bs->nr_ops[cookie->type]++;
+    bs->total_time_ns[cookie->type] += get_clock() - cookie->start_time_ns;
 }
 
 int bdrv_img_create(const char *filename, const char *fmt,