linux-kernel - [PATCH] tools/power/x86/intel_pstate_tracer: Free the trace buffer memory

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Date:   Fri,  5 Jan 2018 14:31:16 -0800
From:   Doug Smythies <doug.smythies@...il.com>
To:     srinivas.pandruvada@...ux.intel.com
Cc:     dsmythies@...us.net, rjw@...ysocki.net,
        linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org
Subject: [PATCH] tools/power/x86/intel_pstate_tracer: Free the trace buffer memory

The trace buffer memory should be, mostly, freed after
the buffer has been output.

This patch is required before a future patch that will allow
the user to override the default, and specify the trace buffer
memory allocation as a command line option.

Signed-off-by: Doug Smythies <dsmythies@...us.net>
---
 .../power/x86/intel_pstate_tracer/intel_pstate_tracer.py  | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/tools/power/x86/intel_pstate_tracer/intel_pstate_tracer.py b/tools/power/x86/intel_pstate_tracer/intel_pstate_tracer.py
index 0b24dd9..29f50d4 100755
--- a/tools/power/x86/intel_pstate_tracer/intel_pstate_tracer.py
+++ b/tools/power/x86/intel_pstate_tracer/intel_pstate_tracer.py
@@ -411,6 +411,16 @@ def set_trace_buffer_size():
         print('IO error setting trace buffer size ')
         quit()
 
+def free_trace_buffer():
+    """ Free the trace buffer memory """
+
+    try:
+       open('/sys/kernel/debug/tracing/buffer_size_kb'
+                 , 'w').write("1")
+    except:
+        print('IO error setting trace buffer size ')
+        quit()
+
 def read_trace_data(filename):
     """ Read and parse trace data """
 
@@ -583,4 +593,9 @@ 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('../../')
-- 
2.7.4