perf: don't start perfetto when disabled with argument

Reviewed-by: Gert Wollny <gert.wollny@collabora.com>

perf-testing/Docker/run.sh

@@ -152,6 +152,11 @@ fi
 echo 0 > /sys/kernel/debug/tracing/tracing_on
 echo nop > /sys/kernel/debug/tracing/current_tracer
 
+if [  "x$perfetto_loops" != "x" ] ; then
+   echo "perfetto_loops parameter not given"
+fi
+
+if [ "x$perfetto_loops" != "x0" ]; then
     /perfetto/out/dist/traced &
     /perfetto/out/dist/traced_probes &
     sleep 1
@@ -160,17 +165,10 @@ sleep 1
     /perfetto/out/dist/perfetto --txt -c /usr/local/perfetto-host.cfg -o /tmp/perfetto-host.trace --detach=mykey
     sleep 1
 
-if [  "x$perfetto_loops" != "x" ] ; then
-   echo "perfetto_loops parameter not given"
-fi
-
     echo "Replaying for Perfetto:"
-LOOP=
-if [ "x$perfetto_loops" != "x0" ]; then
-    LOOP="--loop=$perfetto_loops"
+    eglretrace --benchmark --singlethread --loop=$perfetto_loops $wait_after_frame --headless "/traces-db/${trace}"
 fi
 
-eglretrace --benchmark --singlethread $LOOP $wait_after_frame --headless "/traces-db/${trace}"
 
 iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
 echo 1 > /proc/sys/net/ipv4/ip_forward
@@ -212,6 +210,7 @@ crosvm run \
 rm -f /traces-db/current_trace
 rm -f /traces-db/command
 
+if [ "x$perfetto_loops" != "x0" ]; then
     /perfetto/out/dist/perfetto --attach=mykey --stop
 
     mv /tmp/perfetto-host.trace "$host_perf"
@@ -224,4 +223,6 @@ kill `pidof traced_probes` || echo "traced_probes was not running (anymore)"
     kill `pidof traced` || echo "traced was not running (anymore="
 
     /usr/local/merge_traces.py "$host_perf" "$guest_perf" "$summary_perf"
+fi
+
 sleep 1

perf-testing/Docker/run_traces.sh

@@ -88,6 +88,7 @@ echo nop > /sys/kernel/debug/tracing/current_tracer
 echo "Guest:"
 wflinfo --platform surfaceless_egl --api gles2 -v
 
+if [ "x$perfetto_loops" != "x" -a "x$perfetto_loops" != "x0" ]; then
     /perfetto/out/dist/traced &
     /perfetto/out/dist/traced_probes &
     sleep 1
@@ -98,16 +99,12 @@ sleep 1
     # The first virtio-gpu event has to be captured in the guest, so we correlate correctly to the host event
 
     echo "Replaying for Perfetto:"
-LOOP=
-if [ "x$perfetto_loops" != "x" -a "x$perfetto_loops" != "x0" ]; then
-   LOOP="--loop=$perfetto_loops"
-fi
-
-eglretrace --benchmark --singlethread $LOOP $WAIT --headless "$trace"
+    eglretrace --benchmark --singlethread --loop=$perfetto_loops $WAIT --headless "$trace"
     sleep 1
 
     /perfetto/out/dist/perfetto --attach=mykey --stop
     chmod a+rw "$guest_perf"
+fi
 
 if [ "x$benchmark_loops" != "x0" ]; then
    echo "Measuring rendering times:"