X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=tests%2Fbenchmark%2Ftest_benchmark;h=33e5ed49a3c9ae3299b4a3f0ad2e525be55e7e23;hb=89a8858dc6fdaf6c094d9038db79fbc61469ccef;hp=1fa009ef3df9f53be50de70f72733fa47945ef0d;hpb=3b2e18579fd7ae05607a7c1ba1265848736f98e3;p=lttng-ust.git

diff --git a/tests/benchmark/test_benchmark b/tests/benchmark/test_benchmark
index 1fa009ef..33e5ed49 100755
--- a/tests/benchmark/test_benchmark
+++ b/tests/benchmark/test_benchmark
@@ -1,4 +1,6 @@
 #!/bin/bash
+
+# SPDX-FileCopyrightText: 2023 EfficiOS, Inc
 #
 # SPDX-License-Identifier: LGPL-2.1-only
 
@@ -8,45 +10,44 @@ source $TESTDIR/utils/tap.sh
 
 plan_tests 1
 
-: ${ITERS:=20}
-: ${NR_EVENTS:=7000000}
-: ${NR_CPUS:=1}
+: ${ITERS:=10}
+: ${DURATION:=2}
+: ${NR_THREADS:=1}
+: ${NR_CPUS:=$(lscpu | grep "^CPU(s)" | sed 's/^.*:[ \t]*//g')}
 
 : ${TIME:="./$CURDIR/ptime"}
 
-: ${PROG_NOTRACING:="./$CURDIR/bench1 $NR_CPUS $NR_EVENTS"}
-: ${PROG_TRACING:="./$CURDIR/bench2 $NR_CPUS $NR_EVENTS"}
+: ${PROG_NOTRACING:="./$CURDIR/bench1 $NR_THREADS $DURATION"}
+: ${PROG_TRACING:="./$CURDIR/bench2 $NR_THREADS $DURATION"}
 
 function signal_cleanup ()
 {
 	killall lttng-sessiond
+	exit
 }
 
 trap signal_cleanup SIGTERM SIGINT
 
-CMD_NOTRACING="$TIME '$PROG_NOTRACING >/dev/null 2>&1'"
-CMD_TRACING="$TIME '$PROG_TRACING >/dev/null 2>&1'"
+CMD_NOTRACING="$TIME '$PROG_NOTRACING'"
+CMD_TRACING="$TIME '$PROG_TRACING'"
+
+NR_ACTIVE_CPUS=$(( $NR_CPUS > $NR_THREADS ? $NR_THREADS : $NR_CPUS ))
 
-time_notrace=0
 for i in $(seq $ITERS); do
-	if [[ $EUID -eq 0 ]]; then
-		echo 3 >/proc/sys/vm/drop_caches
-	fi
-	time_notrace="$time_notrace+$(sh -c "$CMD_NOTRACING")"
+	res=$(sh -c "$CMD_NOTRACING")
+	loops_notrace[$i]=$(echo "${res}" | grep "^Number of loops:" | sed 's/^.*: //g')
+	time_notrace[$i]=$(echo "${res}" | grep "^Wall time:" | sed 's/^.*: //g')
 done
 
-
 lttng-sessiond -d --no-kernel
 lttng -q create --snapshot
 lttng -q enable-event -u -a
 lttng -q start
 
-time_trace=0
 for i in $(seq $ITERS); do
-	if [[ $EUID -eq 0 ]]; then
-		echo 3 >/proc/sys/vm/drop_caches
-	fi
-	time_trace="$time_trace+$(sh -c "$CMD_TRACING")"
+	res=$(sh -c "$CMD_TRACING")
+	loops_trace[$i]=$(echo "${res}" | grep "^Number of loops:" | sed 's/^.*: //g')
+	time_trace[$i]=$(echo "${res}" | grep "^Wall time:" | sed 's/^.*: //g')
 done
 
 lttng -q stop
@@ -54,9 +55,31 @@ lttng -q destroy
 killall lttng-sessiond
 
 pass "Trace benchmark"
-S_PER_EVENT=$(echo "( ($time_trace) - ($time_notrace) ) / $ITERS / $NR_EVENTS" | bc -l)
-NS_PER_EVENT=$(echo "$S_PER_EVENT * 1000000000" | bc -l)
+
+# Multiply the wall time by the number of active CPUs to get the
+# overhead of events on each active cpu.
+
+avg_delta=0
+for i in $(seq $ITERS); do
+	delta[$i]=$(echo "((${time_trace[$i]} * ${NR_ACTIVE_CPUS} / ${loops_trace[$i]}) - (${time_notrace[$i]} * ${NR_ACTIVE_CPUS} / ${loops_notrace[$i]}))" | 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%%.*}
 
-diag "Average tracing overhead per event is ${NS_PER_EVENT}ns"
+STD_DEV_NS_PER_EVENT=$(echo "($std_dev * 1000000000)" | bc -l)
+# Remove fractions
+STD_DEV_NS_PER_EVENT=${STD_DEV_NS_PER_EVENT%%.*}
+
+diag "Average tracing overhead per event is ${NS_PER_EVENT}ns, std.dev.: ${STD_DEV_NS_PER_EVENT}ns { NR_THREADS=${NR_THREADS}, NR_ACTIVE_CPUS=${NR_ACTIVE_CPUS} }"