Allow a region to collect a latency histogram that only accounts
writes.
https://virtuozzo.atlassian.net/browse/VSTOR-103846
Signed-off-by: Andrey Zhadchenko <[email protected]>
---
Documentation/admin-guide/device-mapper/statistics.rst | 7 +++++--
drivers/md/dm-stats.c | 10 +++++++++-
2 files changed, 14 insertions(+), 3 deletions(-)
diff --git a/Documentation/admin-guide/device-mapper/statistics.rst
b/Documentation/admin-guide/device-mapper/statistics.rst
index 28e2f9c49ddcb..99b8ad45d47fd 100644
--- a/Documentation/admin-guide/device-mapper/statistics.rst
+++ b/Documentation/admin-guide/device-mapper/statistics.rst
@@ -98,6 +98,9 @@ Messages
rd_histogram:n1,n2,n3,n4,...
collect a latency histogram like "histogram", but only
account read requests.
+ wr_histogram:n1,n2,n3,n4,...
+ collect a latency histogram like "histogram", but only
+ account write requests.
Multiple histogram arguments may be specified for one region;
each histogram is reported as an additional counter set in the
@stats_print output, in the order the histograms were specified.
@@ -145,8 +148,8 @@ Messages
precise_timestamps hist_total_latency histogram:n1,n2,n3,...
The strings "precise_timestamps", "hist_total_latency" and
- "histogram" (also "rd_histogram") are printed only if they were
- specified when creating the region.
+ "histogram" (also "rd_histogram" and "wr_histogram") are printed
+ only if they were specified when creating the region.
@stats_print <region_id> [<starting_line> <number_of_lines>]
Print counters for each step-sized area of a region.
diff --git a/drivers/md/dm-stats.c b/drivers/md/dm-stats.c
index 51827e34d2a8b..b8546744950f3 100644
--- a/drivers/md/dm-stats.c
+++ b/drivers/md/dm-stats.c
@@ -52,7 +52,7 @@ enum {
#define DM_STAT_CLASSES_DATA ((1 << DM_STAT_CLASS_READ) | \
(1 << DM_STAT_CLASS_WRITE))
-#define DM_STAT_MAX_HISTOGRAMS 2
+#define DM_STAT_MAX_HISTOGRAMS 3
struct dm_stat_histogram {
unsigned int class_mask; /* classes this histogram accounts */
@@ -545,6 +545,8 @@ static const char *dm_stat_histogram_name(unsigned int
class_mask)
switch (class_mask) {
case 1 << DM_STAT_CLASS_READ:
return "rd_histogram";
+ case 1 << DM_STAT_CLASS_WRITE:
+ return "wr_histogram";
default:
return "histogram";
}
@@ -1206,6 +1208,12 @@ static int message_stats_create(struct mapped_device *md,
a + 13);
if (r)
goto ret;
+ } else if (!strncasecmp(a, "wr_histogram:", 13)) {
+ r = add_histogram(histograms, &n_histograms,
+ 1 << DM_STAT_CLASS_WRITE,
+ a + 13);
+ if (r)
+ goto ret;
} else
goto ret_einval;
}
--
2.43.5
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