Repeat Chromium Tryserver page_set runs to reduce variance.

cluster_telemetry/telemetry_slave_scripts/vm_run_telemetry.sh

 #!/bin/bash
 #
 # Runs all steps in vm_setup_slave.sh, calls run_multipage_benchmarks and copies
 # the output (if any) to Google Storage.
 #
 # The script should be run from the cluster-telemetry-slave GCE instance's
 # /b/skia-repo/buildbot/cluster_telemetry/telemetry_slave_scripts
 # directory.
 #
 # Copyright 2013 Google Inc. All Rights Reserved.
@@ skipping 43 matching lines @@
 if [ $? -eq 1 ]; then
   gsutil cp gs://chromium-skia-gm/telemetry/webpages_archive/slave$SLAVE_NUM/$PAGESETS_TYPE/* \
     /b/storage/webpages_archive/$PAGESETS_TYPE
 fi
 
 if [[ ! -z "$WHITELIST_GS_LOCATION" ]]; then
   # Copy the whitelist from Google Storage to /tmp.
   gsutil cp $WHITELIST_GS_LOCATION /tmp/$WHITELIST_FILE
 fi
 
+# The number of times to repeate telemetry page_set runs.
+REPEAT_TELEMETRY_RUNS=${REPEAT_TELEMETRY_RUNS:=3}
+
 if [ "$TELEMETRY_BENCHMARK" == "skpicture_printer" ]; then
   # Clean and create the skp output directory.
   sudo chown -R chrome-bot:chrome-bot /b/storage/skps/$PAGESETS_TYPE/$CHROMIUM_BUILD_DIR
   rm -rf /b/storage/skps/$PAGESETS_TYPE/$CHROMIUM_BUILD_DIR
   mkdir -p /b/storage/skps/$PAGESETS_TYPE/$CHROMIUM_BUILD_DIR/
   EXTRA_ARGS="--skp-outdir=/b/storage/skps/$PAGESETS_TYPE/$CHROMIUM_BUILD_DIR/ $EXTRA_ARGS"
+  # Only do one run for SKPs.
+  REPEAT_TELEMETRY_RUNS=1
 fi
 
 if [ "$TELEMETRY_BENCHMARK" == "smoothness" ]; then
   # A synthetic scroll needs to be able to output at least two frames. Make the
   # viewport size smaller than the page size.
   EXTRA_BROWSER_ARGS="--window-size=1280,512"
 fi
 
 OUTPUT_DIR=/b/storage/telemetry_outputs/$RUN_ID
 mkdir -p $OUTPUT_DIR
 
+# Change all local page_sets to use 0 wait seconds.
+find /home/default/storage/page_sets/$PAGESETS_TYPE/ -type f -exec sed -i "s/\"seconds\": 5/\"seconds\": 0/g" {} \;
+
+# Start the timer.
+TIMER="$(date +%s)"
+
 for page_set in /b/storage/page_sets/$PAGESETS_TYPE/*.json; do
   if [[ -f $page_set ]]; then
     if [[ ! -z "$WHITELIST_GS_LOCATION" ]]; then
       check_pageset_url_in_whitelist $page_set /tmp/$WHITELIST_FILE
       if [ $? -eq 1 ]; then
         # The current page set URL does not exist in the whitelist, move on to
         # the next one.
         echo "========== Skipping $page_set because it is not in the whitelist =========="
         continue
       fi
     fi
     echo "========== Processing $page_set =========="
     page_set_basename=`basename $page_set`
     check_and_run_xvfb
     if [ "$TELEMETRY_BENCHMARK" != "skpicture_printer" ]; then
        # Need to capture output for all benchmarks except skpicture_printer.
        OUTPUT_DIR_ARG="-o $OUTPUT_DIR/${RUN_ID}.${page_set_basename}"
     fi
     echo "=== Running: eval sudo DISPLAY=:0 timeout 300 src/tools/perf/run_measurement --extra-browser-args=\"--disable-setuid-sandbox --enable-software-compositing $EXTRA_BROWSER_ARGS\" --browser-executable=/b/storage/chromium-builds/${CHROMIUM_BUILD_DIR}/chrome --browser=exact $TELEMETRY_BENCHMARK $page_set $EXTRA_ARGS $OUTPUT_DIR_ARG ==="
-    eval sudo DISPLAY=:0 timeout 300 src/tools/perf/run_measurement --extra-browser-args=\"--disable-setuid-sandbox --enable-software-compositing\" --browser-executable=/b/storage/chromium-builds/${CHROMIUM_BUILD_DIR}/chrome --browser=exact $TELEMETRY_BENCHMARK $page_set $EXTRA_ARGS $OUTPUT_DIR_ARG
-    sudo chown chrome-bot:chrome-bot $OUTPUT_DIR/${RUN_ID}.${page_set_basename}
+
+    for current_run in `seq 1 $REPEAT_TELEMETRY_RUNS`;
+    do
+      echo "This is run number $current_run"
+      eval sudo DISPLAY=:0 timeout 300 src/tools/perf/run_measurement --extra-browser-args=\"--disable-setuid-sandbox --enable-software-compositing\" --browser-executable=/b/storage/chromium-builds/${CHROMIUM_BUILD_DIR}/chrome --browser=exact $TELEMETRY_BENCHMARK $page_set $EXTRA_ARGS ${OUTPUT_DIR_ARG}.${current_run}
+      sudo chown chrome-bot:chrome-bot $OUTPUT_DIR/${RUN_ID}.${page_set_basename}.${current_run}
+    done
+
     if [ $? -eq 124 ]; then
       echo "========== $page_set timed out! =========="
     else
       echo "========== Done with $page_set =========="
     fi
   fi
 done
 
+TELEMETRY_TIME="$(($(date +%s)-TIMER))"
+echo "Going through all page_sets took $TELEMETRY_TIME seconds"
+
 # Consolidate outputs from all page sets into a single file with special
 # handling for CSV files.
 mkdir $OUTPUT_DIR/${RUN_ID}
 
 for output in $OUTPUT_DIR/${RUN_ID}.*; do
   if [[ "$EXTRA_ARGS" == *--output-format=csv* ]]; then
     csv_basename=`basename $output`
     mv $output $OUTPUT_DIR/${RUN_ID}/${csv_basename}.csv
   else
     cat $output >> $OUTPUT_DIR/output.${RUN_ID}
@@ skipping 55 matching lines @@
   TIMESTAMP=`date +%s`
   echo $TIMESTAMP > /tmp/$TIMESTAMP
   cp /tmp/$TIMESTAMP /b/storage/skps/$PAGESETS_TYPE/$CHROMIUM_BUILD_DIR/TIMESTAMP
   gsutil cp /tmp/$TIMESTAMP gs://chromium-skia-gm/telemetry/skps/slave$SLAVE_NUM/$PAGESETS_TYPE/$CHROMIUM_BUILD_DIR/TIMESTAMP
   rm /tmp/$TIMESTAMP
 fi
 
 # Clean up logs and the worker file.
 rm -rf ${OUTPUT_DIR}*
 delete_worker_file TELEMETRY_${RUN_ID}