tests: benchmark: use cpu-bound workload, calculate average and std.dev.

[deliverable/lttng-ust.git] / tests / benchmark / test_benchmark

diff --git a/tests/benchmark/test_benchmark b/tests/benchmark/test_benchmark
index c55e3027b261869bcfc3be4bef06dcfd70aedd73..6f0dd7b49851cc106f03884fbf367f97e991c565 100755 (executable)
--- a/tests/benchmark/test_benchmark
+++ b/tests/benchmark/test_benchmark
@@ -6,7 +6,7 @@ source $TESTDIR/utils/tap.sh
 
 plan_tests 1
 
-: ${ITERS:=20}
+: ${ITERS:=10}
 : ${NR_EVENTS:=7000000}
 : ${NR_CPUS:=1}
 
@@ -15,28 +15,56 @@ plan_tests 1
 : ${PROG_NOTRACING:="./$CURDIR/bench1 $NR_CPUS $NR_EVENTS"}
 : ${PROG_TRACING:="./$CURDIR/bench2 $NR_CPUS $NR_EVENTS"}
 
+function signal_cleanup ()
+{
+       killall lttng-sessiond
+}
+
+trap signal_cleanup SIGTERM SIGINT
+
 CMD_NOTRACING="$TIME '$PROG_NOTRACING >/dev/null 2>&1'"
 CMD_TRACING="$TIME '$PROG_TRACING >/dev/null 2>&1'"
 
-time_notrace=0
 for i in $(seq $ITERS); do
-       echo 3 >/proc/sys/vm/drop_caches
-       time_notrace="$time_notrace+$(sh -c "$CMD_NOTRACING")"
+       time_notrace[i]=$(sh -c "$CMD_NOTRACING")
 done
 
+
 lttng-sessiond -d --no-kernel
-lttng -q create
+lttng -q create --snapshot
 lttng -q enable-event -u -a
 lttng -q start
 
-time_trace=0
 for i in $(seq $ITERS); do
-       echo 3 >/proc/sys/vm/drop_caches
-       time_trace="$time_trace+$(sh -c "$CMD_TRACING")"
+       time_trace[i]=$(sh -c "$CMD_TRACING")
 done
 
 lttng -q stop
 lttng -q destroy
+killall lttng-sessiond
 
 pass "Trace benchmark"
-diag "Average tracing overhead per event is $(echo "scale=6;( ($time_trace) - ($time_notrace) ) / $ITERS / $NR_EVENTS" | bc -l)s"
+
+avg_delta=0
+for i in $(seq $ITERS); do
+       delta[$i]=$(echo "( ((${time_trace[$i]}) - (${time_notrace[$i]})) / $NR_EVENTS)" | bc -l)
+       avg_delta=$(echo "(${avg_delta} + ${delta[$i]})" | bc -l)
+done
+avg_delta=$(echo "(${avg_delta} / $ITERS)" | bc -l)
+
+std_dev=0
+for i in $(seq $ITERS); do
+       dev[$i]=$(echo "(( (${delta[$i]}) - (${avg_delta}) ) ^ 2)" | bc -l)
+       std_dev=$(echo "( (${std_dev}) + (${dev[i]}) )" | bc -l)
+done
+std_dev=$(echo "( (${std_dev}) / $ITERS )" | bc -l)
+std_dev=$(echo "(sqrt(${std_dev}))" | bc -l)
+
+NS_PER_EVENT=$(echo "($avg_delta * 1000000000)" | bc -l)
+# Remove fractions
+NS_PER_EVENT=${NS_PER_EVENT%%.*}
+
+STD_DEV_NS_PER_EVENT=$(echo "($std_dev * 1000000000)" | bc -l)
+STD_DEV_NS_PER_EVENT=${STD_DEV_NS_PER_EVENT%%.*}
+
+diag "Average tracing overhead per event is ${NS_PER_EVENT}ns, std.dev.: ${STD_DEV_NS_PER_EVENT}ns"