Add activationStats.sh script for basic load stats
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..bbe4c6d
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+.stats_output/
\ No newline at end of file
diff --git a/README.md b/README.md
index b62c665..b8e9d41 100644
--- a/README.md
+++ b/README.md
@@ -194,6 +194,13 @@
wsk -i action create helloWeb helloWeb.js --web=true
oc run -it --image williamyeh/wrk wrk --restart=Never --rm --overrides='{"apiVersion":"v1", "spec":{"volumes":[{"name": "data", "emptyDir": {}}], "containers":[{"name": "wrk", "image": "williamyeh/wrk", "args": ["--threads", "4", "--connections", "50", "--duration", "30s", "--latency", "--timeout", "10s", "http://nginx/api/v1/web/whisk.system/default/helloWeb"], "volumeMounts": [{"mountPath": "/data", "name": "data"}]}]}}'
+### Activation statistics
+
+The `bin/activationStats.sh` script can output throughput and waitTime
+numbers for recent function activations. This is useful when
+spot-checking overall system load and how long functions are waiting
+in queues inside OpenWhisk before being invoked.
+
## Common Problems
### Catalog of actions empty
diff --git a/bin/activationStats.sh b/bin/activationStats.sh
new file mode 100755
index 0000000..787d2b6
--- /dev/null
+++ b/bin/activationStats.sh
@@ -0,0 +1,61 @@
+#!/usr/bin/env bash
+
+### Output some basic stats for recent function activations
+
+set -e
+
+func=$1
+count=$2
+
+if [ "${func}x" = "x" ]; then
+ echo "You must supply a function as the first argument"
+ exit 1
+fi
+
+if [ "${count}x" = "x" ]; then
+ echo "No count provided as second argument - defaulting to 200"
+ count=200
+fi
+
+dir=".stats_output/$func"
+mkdir -p $dir
+rm -rf $dir/*
+
+echo "Gathering stats for last $count executions of $func"
+echo ""
+
+step=200
+for skip in {0..10000..200}; do
+ if [[ $skip -ge $count ]]; then
+ break
+ fi
+ limit=$(($skip + $step > $count ? $count - $skip : $step))
+ wsk activation list $func -l $limit -s $skip -f | grep end | awk '{print $2}' | tr -d "," >> $dir/throughput
+ wsk activation list $func -l $limit -s $skip -f | grep -A 1 waitTime | grep value | awk '{print $2}' >> $dir/waitTime
+done
+
+### Throughput
+file="$dir/throughput"
+first=$(sort -n $file | head -n 1)
+last=$(sort -n $file | tail -n 1)
+count=$(wc -l $file | awk '{print $1}')
+
+duration=$(echo "scale=2; ($last - $first) / 1000" | bc)
+throughput=$(echo "scale=2; $count / $duration" | bc)
+echo "Duration: ${duration}s"
+echo "Count: $count"
+echo "Throughput: $throughput per second"
+echo ""
+
+### Wait Time
+file="$dir/waitTime"
+p95=$(sort -n $file | awk '{all[NR] = $0} END{print all[int(NR*0.95 - 0.5)]}')
+p90=$(sort -n $file | awk '{all[NR] = $0} END{print all[int(NR*0.90 - 0.5)]}')
+p75=$(sort -n $file | awk '{all[NR] = $0} END{print all[int(NR*0.75 - 0.5)]}')
+p50=$(sort -n $file | awk '{all[NR] = $0} END{print all[int(NR*0.50 - 0.5)]}')
+
+echo "Wait time percentiles:"
+echo "95th: ${p95}ms"
+echo "90th: ${p90}ms"
+echo "75th: ${p75}ms"
+echo "50th: ${p50}ms"
