Add dropwatch.stp example.

1 files changed, 30 insertions, 0 deletions

diff --git a/testsuite/systemtap.examples/network/dropwatch.stp b/testsuite/systemtap.examples/network/dropwatch.stp
new file mode 100644
index 00000000..bba7ecd2
--- /dev/null
+++ b/testsuite/systemtap.examples/network/dropwatch.stp
@@ -0,0 +1,30 @@
+#!/usr/bin/stap
+
+############################################################
+# Dropwatch.stp
+# Author: Neil Horman <nhorman@redhat.com>
+# An example script to mimic the behavior of the dropwatch utility
+# http://fedorahosted.org/dropwatch
+############################################################
+
+# Array to hold the list of drop points we find
+global locations
+
+# Note when we turn the monitor on and off
+probe begin { printf("Monitoring for dropped packets\n") }
+probe end { printf("Stopping dropped packet monitor\n") }
+
+# increment a drop counter for every location we drop at
+probe kernel.trace("kfree_skb") { locations[$location] <<< 1 }
+
+# Every 5 seconds report our drop locations
+probe timer.sec(5)
+{
+	printf("\n")
+	foreach (l in locations-) {
+		printf("%d packets dropped at location %p\n",
+			   @count(locations[l]), l)
+	}
+	delete locations
+}
+