Added check to see if code is run on Jetson board

llvm/projects/gpu_profiler/include/profiler.h

@@ -65,6 +65,11 @@ private:
     const std::string ddr_power_rail = "/sys/devices/3160000.i2c/i2c-0/0-0041/iio_device/in_power2_input";
     const std::string soc_power_rail = "/sys/devices/3160000.i2c/i2c-0/0-0040/iio_device/in_power1_input";
     const std::string sys_power_rail = "/sys/devices/3160000.i2c/i2c-0/0-0041/iio_device/in_power0_input";
+    // Critical assumption: If this file doesn't exist, then the board isn't a Jetson
+    const std::string jetson_chip_id = "/sys/module/tegra_fuse/parameters/tegra_chip_id";
+
+    // True if running on Jetson, else false
+    bool on_jetson_; 
 
     // An individual power reading
     struct PowerReading {

llvm/projects/gpu_profiler/src/profiler.cpp

-#include "profiler.h"
+#include "profiler.h" 
 
 Profiler::Profiler() : should_run_profiler_(false), should_stop_profiler_(false) {
     // Open all streams. Not done in start_profiler() function bc the streams
@@ -9,8 +9,14 @@ Profiler::Profiler() : should_run_profiler_(false), should_stop_profiler_(false)
     soc_stream_.open(soc_power_rail, std::ifstream::in);
     sys_stream_.open(sys_power_rail, std::ifstream::in);
 
-    if (!cpu_stream_.is_open() || !gpu_stream_.is_open() || !ddr_stream_.is_open()
-                || !soc_stream_.is_open() || !sys_stream_.is_open()) {
+    // Check if the jetson file id file exists to indirectly check architecture 
+    std::ifstream jetson_file(jetson_chip_id);
+    on_jetson_ = jetson_file.good();
+
+    if (on_jetson_ && 
+                (!cpu_stream_.is_open() || !gpu_stream_.is_open() 
+                || !ddr_stream_.is_open() || !soc_stream_.is_open() 
+                || !sys_stream_.is_open())) {
         std::cout << "Failed to open one of the power rails for reading\n";
         exit(1);
     }
@@ -68,16 +74,23 @@ void Profiler::pause_profiler() {
 // Returns this as a pair of <delta time in milliseconds, energy>
 std::pair<double, double> Profiler::get_time_energy() const {
     double total_energy = 0.0;
-
-    std::chrono::time_point<std::chrono::high_resolution_clock> prev_time = start_time_;
-    for (auto reading : power_readings_) {
-        std::chrono::duration<double> duration = reading.time_ - prev_time;
-        total_energy += reading.gpu_ * duration.count();
-        total_energy += reading.ddr_ * duration.count();
-        prev_time = reading.time_;
+    double delta_time = 0.0;
+
+    if (on_jetson_) {
+        std::chrono::time_point<std::chrono::high_resolution_clock> prev_time = start_time_;
+        for (auto reading : power_readings_) {
+            std::chrono::duration<double> duration = reading.time_ - prev_time;
+            total_energy += reading.gpu_ * duration.count();
+            total_energy += reading.ddr_ * duration.count();
+            prev_time = reading.time_;
+        }
+        delta_time = std::chrono::duration<double, std::milli>(prev_time
+                    - start_time_).count();
+    } else {
+        auto last_reading_time = power_readings_[power_readings_.size() - 1].time_;
+        delta_time = std::chrono::duration<double, std::milli>(last_reading_time
+                    - start_time_).count();
     }
-    double delta_time = std::chrono::duration<double, std::milli>(prev_time 
-                - start_time_).count();
     return std::make_pair(delta_time, total_energy);
 }