tools/power/x86/intel_pstate_tracer: Add optional setting of trace buffer memory allocation

Allow the user to override the default trace buffer memory allocation
by adding a command line option to override the default.

The patch also:

Adds a SIGINT (i.e. CTRL C exit) handler,
so that things can be cleaned up before exit.

Moves the postion of some other cleanup from after to
before the potential "No valid data to plot" exit.

Replaces all quit() calls with sys.exit, because
quit() is not supposed to be used in scripts.
Signed-off-by: Doug Smythies <dsmythies@telus.net>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

tools/power/x86/intel_pstate_tracer/intel_pstate_tracer.py

@@ -28,6 +28,7 @@ import subprocess
 import os
 import time
 import re
+import signal
 import sys
 import getopt
 import Gnuplot
@@ -78,11 +79,12 @@ def print_help():
     print('    Or')
     print('      ./intel_pstate_tracer.py [--cpu cpus] ---trace_file <trace_file> --name <test_name>')
     print('    To generate trace file, parse and plot, use (sudo required):')
-    print('      sudo ./intel_pstate_tracer.py [-c cpus] -i <interval> -n <test_name>')
+    print('      sudo ./intel_pstate_tracer.py [-c cpus] -i <interval> -n <test_name> -m <kbytes>')
     print('    Or')
-    print('      sudo ./intel_pstate_tracer.py [--cpu cpus] --interval <interval> --name <test_name>')
+    print('      sudo ./intel_pstate_tracer.py [--cpu cpus] --interval <interval> --name <test_name> --memory <kbytes>')
     print('    Optional argument:')
-    print('      cpus:  comma separated list of CPUs')
+    print('      cpus:   comma separated list of CPUs')
+    print('      kbytes: Kilo bytes of memory per CPU to allocate to the trace buffer. Default: 10240')
     print('  Output:')
     print('    If not already present, creates a "results/test_name" folder in the current working directory with:')
     print('      cpu.csv - comma seperated values file with trace contents and some additional calculations.')
@@ -379,7 +381,7 @@ def clear_trace_file():
         f_handle.close()
     except:
         print('IO error clearing trace file ')
-        quit()
+        sys.exit(2)
 
 def enable_trace():
     """ Enable trace """
@@ -389,7 +391,7 @@ def enable_trace():
                  , 'w').write("1")
     except:
         print('IO error enabling trace ')
-        quit()
+        sys.exit(2)
 
 def disable_trace():
     """ Disable trace """
@@ -399,17 +401,17 @@ def disable_trace():
                  , 'w').write("0")
     except:
         print('IO error disabling trace ')
-        quit()
+        sys.exit(2)
 
 def set_trace_buffer_size():
     """ Set trace buffer size """
 
     try:
-       open('/sys/kernel/debug/tracing/buffer_size_kb'
-                 , 'w').write("10240")
+       with open('/sys/kernel/debug/tracing/buffer_size_kb', 'w') as fp:
+          fp.write(memory)
     except:
-        print('IO error setting trace buffer size ')
-        quit()
+       print('IO error setting trace buffer size ')
+       sys.exit(2)
 
 def free_trace_buffer():
     """ Free the trace buffer memory """
@@ -418,8 +420,8 @@ def free_trace_buffer():
        open('/sys/kernel/debug/tracing/buffer_size_kb'
                  , 'w').write("1")
     except:
-        print('IO error setting trace buffer size ')
-        quit()
+        print('IO error freeing trace buffer ')
+        sys.exit(2)
 
 def read_trace_data(filename):
     """ Read and parse trace data """
@@ -431,7 +433,7 @@ def read_trace_data(filename):
         data = open(filename, 'r').read()
     except:
         print('Error opening ', filename)
-        quit()
+        sys.exit(2)
 
     for line in data.splitlines():
         search_obj = \
@@ -489,10 +491,22 @@ def read_trace_data(filename):
 # Now seperate the main overall csv file into per CPU csv files.
     split_csv()
 
+def signal_handler(signal, frame):
+    print(' SIGINT: Forcing cleanup before exit.')
+    if interval:
+        disable_trace()
+        clear_trace_file()
+        # Free the memory
+        free_trace_buffer()
+        sys.exit(0)
+
+signal.signal(signal.SIGINT, signal_handler)
+
 interval = ""
 filename = ""
 cpu_list = ""
 testname = ""
+memory = "10240"
 graph_data_present = False;
 
 valid1 = False
@@ -501,7 +515,7 @@ valid2 = False
 cpu_mask = zeros((MAX_CPUS,), dtype=int)
 
 try:
-    opts, args = getopt.getopt(sys.argv[1:],"ht:i:c:n:",["help","trace_file=","interval=","cpu=","name="])
+    opts, args = getopt.getopt(sys.argv[1:],"ht:i:c:n:m:",["help","trace_file=","interval=","cpu=","name=","memory="])
 except getopt.GetoptError:
     print_help()
     sys.exit(2)
@@ -521,6 +535,8 @@ for opt, arg in opts:
     elif opt in ("-n", "--name"):
         valid2 = True
         testname = arg
+    elif opt in ("-m", "--memory"):
+        memory = arg
 
 if not (valid1 and valid2):
     print_help()
@@ -569,6 +585,11 @@ current_max_cpu = 0
 
 read_trace_data(filename)
 
+clear_trace_file()
+# Free the memory
+if interval:
+    free_trace_buffer()
+
 if graph_data_present == False:
     print('No valid data to plot')
     sys.exit(2)
@@ -593,9 +614,4 @@ for root, dirs, files in os.walk('.'):
     for f in files:
         fix_ownership(f)
 
-clear_trace_file()
-# Free the memory
-if interval:
-    free_trace_buffer()
-
 os.chdir('../../')