trappy knows about some trace events. You can add your own in the notebook without having to change any code in trappy. After the trace is registered, the next time you parse a trace file that information will be part of the trace object as a pandas DataFrame and can be analyzed like the other DataFrames in the FTrace class.
The trace event must follow the following format:
title: key0=value0 key1=value1 key2=value2 ...
The title should be something that's unique in the trace. For example, you can generate trace with the following trace_printk():
trace_printk("thermal_gpu_power_get: frequency=%u load=%d\n", freq, load);
which will appear in the trace.txt as:
kworker/6:1-457 [006] 144.439566: bprint: 0xc042f8a0f: thermal_gpu_power_get: frequency=177 load=0
You can add this event to the trace instance using register_dynamic_ftrace()
First import trappy
In [1]:
import sys
sys.path.append("..")
%matplotlib inline
import trappy
Register it. The first argument is the name under which you will find it in the trace instance. It will be changed to lower_case_with_underscores_to_separate_words. The second argument is some unique text in the trace, usually the title:
In [2]:
trappy.register_dynamic_ftrace("gpu_power_in", "thermal_gpu_power_get")
Out[2]:
Now we can parse the trace
In [3]:
trace = trappy.FTrace("/path/to/trace")
trace now has a gpu_power_in member that contains the information. We can see the first few lines of the generated dataframe:
In [5]:
trace.gpu_power_in.data_frame.head()
Out[5]:
We can now plot it or manipulate it as any other DataFrame in pandas
In [8]:
figsize(18, 7)
trace.gpu_power_in.data_frame["frequency"].plot()
Out[8]:
register_dynamic_ftrace() is useful for simple traces in which you don't need to do any post-processing. If you need to register a full-featured trace class you can use trappy.register_ftrace_parser() for this. For example, a class that parses trace for capacity_per_group: and wants to limit the cpumasks to 8-digit could declare it like this:
In [8]:
from trappy.base import Base
class GroupCapacity(Base):
unique_word = "capacity_per_group:"
name = "group_capacity"
_cpus_column = "cpus"
def __init__(self):
super(GroupCapacity, self).__init__(
unique_word=self.unique_word,
)
def finalize_object(self):
if self._cpus_column in self.data_frame.columns:
self.data_frame[self._cpus_column] = self.data_frame[self._cpus_column].apply('{:0>8}'.format)
trappy.register_ftrace_parser(GroupCapacity)
Now after parsing your trace using trappy.FTrace() you can access it's group_capacity member. For example:
trappy.LinePlot(trace, GroupCapacity, column="group_capacity", pivot="cpus", marker='.', linestyle='none', per_line=2).view()