ftrace: add support to report function profiling data

Functions profiling data are reported in a set of files, one for each CPU.

This patch adds the required support to collect these data into a single
JSON formatted file. Data are collected using a shutils routing on the
target side and formatted in JSON on the host side.

Signed-off-by: Patrick Bellasi <patrick.bellasi@arm.com>

devlib/bin/scripts/shutils.in

@@ -43,6 +43,18 @@ cpufreq_trace_all_frequencies() {
 	done
 }
 
+################################################################################
+# FTrace Utility Functions
+################################################################################
+
+ftrace_get_function_stats() {
+    for CPU in $(ls /sys/kernel/debug/tracing/trace_stat | sed 's/function//'); do
+        REPLACE_STRING="s/  Function/\n  Function (CPU$CPU)/"
+        cat /sys/kernel/debug/tracing/trace_stat/function$CPU \
+            | sed "$REPLACE_STRING"
+    done
+}
+
 ################################################################################
 # Main Function Dispatcher
 ################################################################################
@@ -63,6 +75,9 @@ cpufreq_get_all_governors)
 cpufreq_trace_all_frequencies)
     cpufreq_trace_all_frequencies $*
     ;;
+ftrace_get_function_stats)
+    ftrace_get_function_stats
+    ;;
 *)
     echo "Command [$CMD] not supported"
     exit -1

devlib/trace/ftrace.py

@@ -15,7 +15,9 @@
 
 from __future__ import division
 import os
+import json
 import time
+import re
 import subprocess
 
 from devlib.trace import TraceCollector
@@ -27,6 +29,7 @@ from devlib.utils.misc import check_output, which
 TRACE_MARKER_START = 'TRACE_MARKER_START'
 TRACE_MARKER_STOP = 'TRACE_MARKER_STOP'
 OUTPUT_TRACE_FILE = 'trace.dat'
+OUTPUT_PROFILE_FILE = 'trace_stat.dat'
 DEFAULT_EVENTS = [
     'cpu_frequency',
     'cpu_idle',
@@ -40,6 +43,9 @@ DEFAULT_EVENTS = [
 ]
 TIMEOUT = 180
 
+# Regexps for parsing of function profiling data
+CPU_RE = re.compile(r'  Function \(CPU([0-9]+)\)')
+STATS_RE = re.compile(r'([^ ]*) +([0-9]+) +([0-9.]+) us +([0-9.]+) us +([0-9.]+) us')
 
 class FtraceCollector(TraceCollector):
 
@@ -165,6 +171,44 @@ class FtraceCollector(TraceCollector):
             if self.autoview:
                 self.view(outfile)
 
+    def get_stats(self, outfile):
+        if not self.functions:
+            return
+
+        if os.path.isdir(outfile):
+            outfile = os.path.join(outfile, OUTPUT_PROFILE_FILE)
+        output = self.target._execute_util('ftrace_get_function_stats',
+                                            as_root=True)
+
+        function_stats = {}
+        for line in output.splitlines():
+            # Match a new CPU dataset
+            match = CPU_RE.search(line)
+            if match:
+                cpu_id = int(match.group(1))
+                function_stats[cpu_id] = {}
+                self.logger.debug("Processing stats for CPU%d...", cpu_id)
+                continue
+            # Match a new function dataset
+            match = STATS_RE.search(line)
+            if match:
+                fname = match.group(1)
+                function_stats[cpu_id][fname] = {
+                        'hits' : int(match.group(2)),
+                        'time' : float(match.group(3)),
+                        'avg'  : float(match.group(4)),
+                        's_2'  : float(match.group(5)),
+                    }
+                self.logger.debug(" %s: %s",
+                             fname, function_stats[cpu_id][fname])
+
+        self.logger.debug("FTrace stats output [%s]...", outfile)
+        with open(outfile, 'w') as fh:
+           json.dump(function_stats, fh, indent=4)
+        self.logger.info("FTrace function stats save in [%s]", outfile)
+
+        return function_stats
+
     def report(self, binfile, destfile):
         # To get the output of trace.dat, trace-cmd must be installed
         # This is done host-side because the generated file is very large