From 56cdc2e6c3ff51a1fc71e9c47258e7aa905f418e Mon Sep 17 00:00:00 2001
From: Douglas RAILLARD <douglas.raillard@arm.com>
Date: Thu, 31 Oct 2019 17:42:16 +0000
Subject: [PATCH] ftrace: Allow setting the number of cmdlines saved by ftrace
While tracing, ftrace records a mapping of PIDs to cmdlines. By default, it will
only record up to 128 such entries, which is not enough for a typical android
system. The consequence is trace-cmd reporting "<...>" as cmdline.
Allow setting that number to a higher value, and default to a comfortable 4096
entries.
Signed-off-by: Douglas RAILLARD <douglas.raillard@arm.com>
---
devlib/trace/ftrace.py | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/devlib/trace/ftrace.py b/devlib/trace/ftrace.py
index ffe80d3..205746a 100644
--- a/devlib/trace/ftrace.py
+++ b/devlib/trace/ftrace.py
@@ -64,6 +64,7 @@ class FtraceCollector(TraceCollector):
strict=False,
report_on_target=False,
trace_clock='local',
+ saved_cmdlines_nr=4096,
):
super(FtraceCollector, self).__init__(target)
self.events = events if events is not None else DEFAULT_EVENTS
@@ -85,6 +86,7 @@ class FtraceCollector(TraceCollector):
self.event_string = None
self.function_string = None
self.trace_clock = trace_clock
+ self.saved_cmdlines_nr = saved_cmdlines_nr
self._reset_needed = True
# pylint: disable=bad-whitespace
@@ -97,6 +99,7 @@ class FtraceCollector(TraceCollector):
self.marker_file = self.target.path.join(self.tracing_path, 'trace_marker')
self.ftrace_filter_file = self.target.path.join(self.tracing_path, 'set_ftrace_filter')
self.trace_clock_file = self.target.path.join(self.tracing_path, 'trace_clock')
+ self.save_cmdlines_size_file = self.target.path.join(self.tracing_path, 'saved_cmdlines_size')
self.host_binary = which('trace-cmd')
self.kernelshark = which('kernelshark')
@@ -175,6 +178,7 @@ class FtraceCollector(TraceCollector):
self.reset()
self.target.write_value(self.trace_clock_file, self.trace_clock, verify=False)
+ self.target.write_value(self.save_cmdlines_size_file, self.saved_cmdlines_nr)
self.target.execute('{} start {}'.format(self.target_binary, self.event_string),
as_root=True)
if self.automark: