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 <[e-mail]>
Signed-off-by: Rafael J. Wysocki <[e-mail]>

tools/power/x86/intel_pstate_tracer/intel_pstate_tracer.py

···
 import os
 import time
 import re
+import signal
 import sys
 import getopt
 import Gnuplot
···
     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.')
···
         f_handle.close()
     except:
         print('IO error clearing trace file ')
-        quit()
+        sys.exit(2)
 
 def enable_trace():
     """ Enable trace """
···
                  , 'w').write("1")
     except:
         print('IO error enabling trace ')
-        quit()
+        sys.exit(2)
 
 def disable_trace():
     """ 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 """
···
        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 """
···
         data = open(filename, 'r').read()
     except:
         print('Error opening ', filename)
-        quit()
+        sys.exit(2)
 
     for line in data.splitlines():
         search_obj = \
···
 # 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
···
 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)
···
     elif opt in ("-n", "--name"):
         valid2 = True
         testname = arg
+    elif opt in ("-m", "--memory"):
+        memory = arg
 
 if not (valid1 and valid2):
     print_help()
···
 
 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)
···
 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('../../')