153 lines
4.9 KiB
ReStructuredText
153 lines
4.9 KiB
ReStructuredText
.. _acrntrace:
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acrntrace
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#########
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Description
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***********
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``acrntrace`` is a tool running on the Service OS (SOS) to capture trace data.
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A ``scripts`` directory includes scripts to analyze the trace data.
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Usage
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*****
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The ``acrntrace`` tool runs on the Service OS (SOS) to capture trace data and
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output to trace file under ``./acrntrace`` with raw (binary) data format.
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Options:
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-h print this message
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-i period specify polling interval in milliseconds [1-999]
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-t max_time max time to capture trace data (in second)
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-c clear the buffered old data
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-r free_space amount of free space (in MB) remaining on the disk
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before acrntrace stops
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The ``acrntrace_format.py`` is a offline tool for parsing trace data (as output
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by acrntrace) to human-readable formats based on given format.
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Here's an explanation of the tool's parameters:
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.. code-block:: none
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acrntrace_format.py [options] [formats] [trace_data]
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Options:
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-h print this message
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*formats* file specifies the rules to reformat the *trace_data* collected by
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``acrntrace`` into a human-readable text form. The rules in this file are of
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the form::
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event_id text_format_string
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The text_format_string may include format specifiers, such as
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``%(cpu)d``, ``%(tsc)d``, ``%(event)d``, ``%(1)d``, and ``%(2)d``.
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The 'd' format specifier outputs in decimal, alternatively 'x' will
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output in hexadecimal and 'o' will output in octal.
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These respectively correspond to the CPU number (cpu), timestamp
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counter (tsc), event ID (event) and the data logged in the trace file.
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There can be only one such rule for each type of event.
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An example *formats_file* is available in the acrn_hypervisor repo in
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``hypervisor/tools/acrntrace/scripts/formats``.
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The ``acrnalyze.py`` is a offline tool to analyze trace data (as output by
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acrntrace) based on given analyzer, such as ``vm_exit`` or ``irq``.
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Options:
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-h print this message
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-i, --ifile=string input file name
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-o, --ofile=string output filename
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-f, --frequency=unsigned_int TSC frequency in MHz
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--vm_exit generate a vm_exit report
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--irq generate an IRQ-related report
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.. note:: We depend on TSC frequency to do time-based analysis. Please configure
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the right TSC frequency that acrn runs on. TSC frequency can be obtained
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from the ACRN console log (calibrate_tsc, tsc_hz=xxx) when the hypervisor boots.
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The tool does not take into account CPU frequency variation that can
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occur during normal operation (aka CPU throttling) on the processor which
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doesn't support for invariant TSC. The results may therefore not be
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completely accurate in that regard.
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Here's a typical use of ``acrntrace`` to capture trace data from the SOS,
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converting the binary data to human-readable form, copying the processed trace
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data to your linux system, and running the analysis tool.
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1. On the SOS, clear buffers before starting a trace, with:
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.. code-block:: none
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# acrntrace -c
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#. Start capturing buffered trace data with:
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.. code-block:: none
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# acrntrace
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512MB storage space will be reserved by default. This ensures that acrntrace
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will exit automatically when the free storage space on the disk is less than
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reserved space. Reserved space on the disk is configurable through '-r'.
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Trace files are created under ``./acrntrace/``, with a
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date-time-based directory name such as ``20171115-101605``
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#. When done, stop a running ``acrntrace``, with:
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.. code-block:: none
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q <enter>
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#. Convert trace data to human-readable format, with:
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.. code-block:: none
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# acrntrace_format.py formats trace_data
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Trace data will be converted to human-readable format based on given format
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and printed to stdout.
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#. Analysis of the collected data is done on a Linux PC, so you'll need
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to copy the collected trace data to your Linux system (using ``scp`` is
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recommended):
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.. code-block:: none
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# scp -r ./acrntrace/20171115-101605/ \
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username@hostname:/home/username/trace_data
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Replace username and hostname with appropriate values.
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#. On the Linux system, run the provided Python3 script to analyze the
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``vm_exits``, ``irq``:
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.. code-block:: none
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# acrnalyze.py -i /home/xxxx/trace_data/20171115-101605/0 \
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-o /home/xxxx/trace_data/20171115-101605/cpu0 --vm_exit --irq
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- Analysis report is written to stdout, or to a CSV file if
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a filename is specified using ``-o filename``.
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- The scripts require Python3.
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Build and Install
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*****************
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The source files for ``acrntrace`` are in the ``tools/acrntrace`` folder,
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and can be built and installed using:
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.. code-block:: none
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# make
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# make install
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The processing scripts are in ``tools/acrntrace/scripts`` and need to be
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copied to and run on your Linux system.
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