[ovs-dev] [PATCH v3 1/2] coverage: Add command for reading counter value

Jakub Sitnicki jkbs at redhat.com
Wed Jun 6 14:19:33 UTC 2018


Facilitate checking coverage counters from scripts and tests with a new
"coverage/read-counter" command that gets the total count for a counter.

Same could be achieved by scraping the output of "coverage/show" command
but the difficulties there are that output is in human readable format
and zero-value counters are not listed.

Signed-off-by: Jakub Sitnicki <jkbs at redhat.com>
---
 lib/coverage-unixctl.man |  2 ++
 lib/coverage.c           | 42 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 44 insertions(+)

diff --git a/lib/coverage-unixctl.man b/lib/coverage-unixctl.man
index 8e5df818e..81eb93902 100644
--- a/lib/coverage-unixctl.man
+++ b/lib/coverage-unixctl.man
@@ -11,3 +11,5 @@ debugging.
 Displays the averaged per-second rates for the last few seconds, the
 last minute and the last hour, and the total counts of all of the
 coverage counters.
+.IP "\fBcoverage/read-counter\fR \fIcounter\fR"
+Displays the total count for the given coverage \fIcounter\fR.
diff --git a/lib/coverage.c b/lib/coverage.c
index 6cef82614..a95b6aa25 100644
--- a/lib/coverage.c
+++ b/lib/coverage.c
@@ -44,6 +44,8 @@ static unsigned int idx_count = 0;
 static void coverage_read(struct svec *);
 static unsigned int coverage_array_sum(const unsigned int *arr,
                                        const unsigned int len);
+static bool coverage_read_counter(const char *name,
+                                  unsigned long long int *count);
 
 /* Registers a coverage counter with the coverage core */
 void
@@ -72,11 +74,32 @@ coverage_unixctl_show(struct unixctl_conn *conn, int argc OVS_UNUSED,
     svec_destroy(&lines);
 }
 
+static void
+coverage_unixctl_read_counter(struct unixctl_conn *conn, int argc OVS_UNUSED,
+                              const char *argv[], void *aux OVS_UNUSED)
+{
+    unsigned long long count;
+    char *reply;
+    bool ok;
+
+    ok = coverage_read_counter(argv[1], &count);
+    if (!ok) {
+        unixctl_command_reply_error(conn, "No such counter");
+        return;
+    }
+
+    reply = xasprintf("%llu\n", count);
+    unixctl_command_reply(conn, reply);
+    free(reply);
+}
+
 void
 coverage_init(void)
 {
     unixctl_command_register("coverage/show", "", 0, 0,
                              coverage_unixctl_show, NULL);
+    unixctl_command_register("coverage/read-counter", "COUNTER", 1, 1,
+                             coverage_unixctl_read_counter, NULL);
 }
 
 /* Sorts coverage counters in descending order by total, within equal
@@ -372,3 +395,22 @@ coverage_array_sum(const unsigned int *arr, const unsigned int len)
     ovs_mutex_unlock(&coverage_mutex);
     return sum;
 }
+
+static bool
+coverage_read_counter(const char *name, unsigned long long int *count)
+{
+    for (size_t i = 0; i < n_coverage_counters; i++) {
+        struct coverage_counter *c = coverage_counters[i];
+
+        if (!strcmp(c->name, name)) {
+            ovs_mutex_lock(&coverage_mutex);
+            c->total += c->count();
+            *count = c->total;
+            ovs_mutex_unlock(&coverage_mutex);
+
+            return true;
+        }
+    }
+
+    return false;
+}
-- 
2.14.4



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