Backup/restore CPU configuration before/after running benchmarks.

Change-Id: I611bc1e1ed09b10663f91920a49c2830cd142439

3 files changed, 49 insertions, 0 deletions

diff --git a/benchmarks/benchmarks_run_target.sh b/benchmarks/benchmarks_run_target.sh
index 075e637..042216b 100755
--- a/benchmarks/benchmarks_run_target.sh
+++ b/benchmarks/benchmarks_run_target.sh
@@ -212,6 +212,13 @@ main() {
   fi
 
   start_timer "${target_timer_name}"
+
+  # We need to set up an android environment to have access to `adb` for the CPU
+  # config backup helpers.
+  setup_android_target "arm_krait-eng"
+  local -r backup_cpus_config_dir=$(mktemp -d)
+  backup_device_cpus_config "$backup_cpus_config_dir"
+
   for bits in 32 64; do
     if ! ${options["${bits}bit"]}; then
       log I "Skipping ${bits}bit benchmarks."
@@ -233,6 +240,8 @@ main() {
     # Set freq.
     run_all_benchmarks "${bits}"
   done
+
+  restore_device_cpus_config "$backup_cpus_config_dir"
   stop_timer "${target_timer_name}"
 
   log S "$0 Finished!"
diff --git a/devices/cpu_freq_utils.sh b/devices/cpu_freq_utils.sh
index 8132542..c31ac73 100644
--- a/devices/cpu_freq_utils.sh
+++ b/devices/cpu_freq_utils.sh
@@ -129,3 +129,41 @@ get_device_settings() {
 
   safe source "${cpu_freq_script}"
 }
+
+# Arguments:
+#   ${1} - backup directory
+backup_device_cpus_config() {
+  local -r backup_dir="${1}"
+  for remote_cpu_path in $(adb_shell_strip echo "$sys_cpu_path/cpu*"); do
+    if [[ $remote_cpu_path =~ .*cpu([0-9]+)$ ]]; then
+      local cpu_index=${BASH_REMATCH[1]}
+      local local_cpu_path="$backup_dir/cpu$cpu_index"
+      safe mkdir -p "$local_cpu_path/cpufreq"
+      adb pull "$remote_cpu_path/online" "$local_cpu_path"
+      adb pull "$remote_cpu_path/cpufreq/scaling_governor" "$local_cpu_path/cpufreq/"
+      adb pull "$remote_cpu_path/cpufreq/scaling_setspeed" "$local_cpu_path/cpufreq/"
+    fi
+  done
+}
+
+
+# Arguments:
+#   $1 - backup directory
+restore_device_cpus_config() {
+  local -r backup_dir="${1}"
+  for local_cpu_path in "$backup_dir"/*; do
+    local cpu_index=${local_cpu_path#${backup_dir}/cpu}
+    local remote_cpu_path="$sys_cpu_path/cpu$cpu_index"
+    # Note that we do not use `safe` for `online` and `scaling_setspeed`,
+    # because attempting to set those to their current value raises an error.
+    adb shell "echo \"$(cat "$local_cpu_path/online")\" > $remote_cpu_path/online"
+    if [[ -f "$local_cpu_path/cpufreq/scaling_governor" ]]; then
+      safe adb shell "echo \"$(cat "$local_cpu_path/cpufreq/scaling_governor")\" > $remote_cpu_path/cpufreq/scaling_governor"
+    fi
+    local freq=$(cat "$local_cpu_path/cpufreq/scaling_setspeed")
+    if [[ "$freq" =~ ^[0-9]+$ ]]; then
+      adb shell "echo \"$freq\" > $remote_cpu_path/cpufreq/scaling_setspeed"
+    fi
+  done
+  rm -rf "$backup_dir"
+}
diff --git a/utils/utils.sh b/utils/utils.sh
index 8593e69..47480a4 100644
--- a/utils/utils.sh
+++ b/utils/utils.sh
@@ -46,6 +46,8 @@ init_coloured_logging() {
 
 init_shell() {
   enable_error_on_unset_expansion
+  # Use extended globs for pattern matching.
+  shopt -s extglob
 }
 
 # Log function.