[Piglit] [Patch v5 1/4] framework/dmesg: Adds a new module for dmesg

Ilia Mirkin imirkin at alum.mit.edu
Tue Feb 4 10:28:56 PST 2014


On Tue, Feb 4, 2014 at 1:12 PM, Dylan Baker <baker.dylan.c at gmail.com> wrote:
> On Tuesday, February 04, 2014 12:43:42 PM Ilia Mirkin wrote:
>> On Tue, Feb 4, 2014 at 12:35 PM, Dylan Baker <baker.dylan.c at gmail.com>
> wrote:
>> > This modules implements two classes and a helper function. The two
>> > classes are both dmesg wrapper classes, one, PosixDmesg is used on posix
>> > systems when requested to actually do checks on dmesg. The second class,
>> > DummyDmesg, is used to reduce code complexity by providing dummy
>> > versions of the methods in PosixDmesg. This means that we don't need
>> > separate code paths for Posix systems wanting to check dmesg, Posix
>> > systems not wanting to check dmesg, and non-posix systems which lack
>> > dmesg.
>> >
>> > Beyond reducing complexity this module also gives better isolation,
>> > dmesg is only used in Test.execute(), no where else. Additional classes
>> > don't need to worry about dmesg that way, it's just available.
>> >
>> > v2: - Remove unnecessary assert from PosixDmesg.update_result()
>> >
>> >     - simplify replace helper in PoixDmesg.update_result()
>> >     - replace try/except with if check
>> >     - Change PosixDmesg.update_dmesg() to work even if dmesg 'wraps'
>> >
>> > v3: - Try/Except assignment of PosixDmesg._last_message in update_dmesg()
>> >
>> >     - Set the dmesg levels the same as the previous implementation
>> >     - Change PosixDmesg into LinuxDmesg and enforce that dmesg has
>> >
>> >       timestamps
>> >
>> > v4: - Add check in LinuxDmesg.__init__ to ensure there is something in
>> >
>> >       dmesg before doing the timestamp check. This should make problems
>> >       clearer
>> >
>> >     - Refactor some code in LinuxDmesg.update_result()
>> >
>> > v5: - Replace exception with warning.
>> >
>> >     - add break to loop in dmesg.update_dmesg
>> >
>> > Signed-off-by: Dylan Baker <baker.dylan.c at gmail.com>
>> > ---
>> >
>> >  framework/dmesg.py | 175
>> >  +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed,
>> >  175 insertions(+)
>> >  create mode 100644 framework/dmesg.py
>> >
>> > diff --git a/framework/dmesg.py b/framework/dmesg.py
>> > new file mode 100644
>> > index 0000000..feb05ad
>> > --- /dev/null
>> > +++ b/framework/dmesg.py
>> > @@ -0,0 +1,175 @@
>> > +# Copyright (c) 2013-2014 Intel Corporation
>> > +#
>> > +# Permission is hereby granted, free of charge, to any person obtaining a
>> > +# copy of this software and associated documentation files (the
>> > "Software"), +# to deal in the Software without restriction, including
>> > without limitation +# the rights to use, copy, modify, merge, publish,
>> > distribute, sublicense, +# and/or sell copies of the Software, and to
>> > permit persons to whom the +# Software is furnished to do so, subject to
>> > the following conditions: +#
>> > +# The above copyright notice and this permission notice (including the
>> > next +# paragraph) shall be included in all copies or substantial
>> > portions of the +# Software.
>> > +#
>> > +# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
>> > OR +# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
>> > MERCHANTABILITY, +# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
>> >  IN NO EVENT SHALL +# THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
>> > CLAIM, DAMAGES OR OTHER +# LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
>> > TORT OR OTHERWISE, ARISING +# FROM, OUT OF OR IN CONNECTION WITH THE
>> > SOFTWARE OR THE USE OR OTHER DEALINGS +# IN THE SOFTWARE.
>> > +
>> > +""" Module implementing classes for reading posix dmesg
>> > +
>> > +Currently this module only has the default DummyDmesg, and a LinuxDmesg.
>> > +The method used on Linux requires that timetamps are enabled, and no
>> > other
>> > +posix system has timestamps.
>> > +
>> > +On OSX and *BSD one would likely want to implement a system that reads
>> > the
>> > +sysloger, since timestamps can be added by the sysloger, and are not
>> > inserted +by dmesg.
>> > +
>> > +"""
>> > +
>> > +import re
>> > +import sys
>> > +import subprocess
>> > +import warnings
>> > +
>> > +__all__ = ['LinuxDmesg', 'DummyDmesg', 'get_dmesg']
>> > +
>> > +
>> > +class LinuxDmesg(object):
>> > +    """ Read dmesg on posix systems
>> > +
>> > +    This reads the dmesg ring buffer, stores the contents of the buffer,
>> > and +    then compares it whenever called, returning the difference
>> > between the +    calls. It requires timestamps to be enabled.
>> > +
>> > +    """
>> > +    DMESG_COMMAND = ['dmesg', '--level',
>> > 'emerg,alert,crit,err,warn,notice'] +
>> > +    def __init__(self):
>> > +        """ Create a dmesg instance """
>> > +        self._last_message = None
>> > +        self._new_messages = []
>> > +
>> > +        # Populate self.dmesg initially, otherwise the first test will
>> > always +        # be full of dmesg crud.
>> > +        self.update_dmesg()
>> > +
>> > +        if not self._last_message:
>> > +            # We need to ensure that there is something in dmesg to check
>> > +            # timestamps.
>> > +            warnings.warn("Cannot check dmesg for timestamp support. If
>> > you " +                          "do not have timestamps enabled in your
>> > kernel you " +                          "get incomplete dmesg captures",
>> > RuntimeWarning) +        elif not re.match(r'\[\s*\d+\.\d+\]',
>> > self._last_message): +            # Do an initial check to ensure that
>> > dmesg has timestamps, we need +            # timestamps to work
>> > correctly. A proper linux dmesg timestamp +            # looks like this:
>> > [    0.00000]
>> > +            raise DmesgError(
>> > +                "Your kernel does not seem to support timestamps, which "
>> > +                "are required by the --dmesg option")
>>
>> Consider also making this a warning.
>>
>> Either way, Reviewed-by: Ilia Mirkin <imirkin at alum.mit.edu>
>>
>> > +
>> > +    def update_result(self, result):
>> > +        """ Takes a TestResult object and updates it with dmesg statuses
>> > +
>> > +        If dmesg is enabled, and if dmesg has been updated, then replace
>> > pass +        with dmesg-warn and warn and fail with dmesg-fail. If dmesg
>> > has not +        been updated, it will return the original result passed
>> > in. +
>> > +        Arguments:
>> > +        result -- A TestResult instance
>> > +
>> > +        """
>> > +
>> > +        def replace(res):
>> > +            """ helper to replace statuses with the new dmesg status
>> > +
>> > +            Replaces pass with dmesg-warn, and warn and fail with
>> > dmesg-fail, +            otherwise returns the input
>> > +
>> > +            """
>> > +            return {"pass": "dmesg-warn",
>> > +                    "warn": "dmesg-fail",
>> > +                    "fail": "dmesg-fail"}.get(res, res)
>> > +
>> > +        # Get a new snapshot of dmesg
>> > +        self.update_dmesg()
>> > +
>> > +        # if update_dmesg() found new entries replace the results of the
>> > test +        # and subtests
>> > +        if self._new_messages:
>> > +            result['result'] = replace(result['result'])
>> > +
>> > +            # Replace any subtests
>> > +            if 'subtest' in result:
>> > +                for key, value in result['subtest'].iteritems():
>> > +                    result['subtest'][key] = replace(value)
>> > +
>> > +            # Add the dmesg values to the result
>> > +            result['dmesg'] = self._new_messages
>> > +
>> > +        return result
>> > +
>> > +    def update_dmesg(self):
>> > +        """ Call dmesg using subprocess.check_output
>> > +
>> > +        Get the contents of dmesg, then calculate new messages, finally
>> > set +        self.dmesg equal to the just read contents of dmesg.
>> > +
>> > +        """
>> > +        dmesg =
>> > subprocess.check_output(self.DMESG_COMMAND).strip().splitlines() +
>> > +        # Find all new entries, do this by slicing the list of dmesg to
>> > only +        # returns elements after the last element stored. If there
>> > are not +        # matches a value error is raised, that means all of
>> > dmesg is new +        l = 0
>> > +        for index, item in enumerate(reversed(dmesg)):
>> > +            if item == self._last_message:
>> > +                l = len(dmesg) - index  # don't include the matched
>> > element +                break
>> > +        self._new_messages = dmesg[l:]
>> > +
>> > +        # Attempt to store the last element of dmesg, unless there was no
>> > dmesg +        self._last_message = dmesg[-1] if dmesg else None
>> > +
>> > +
>> > +class DummyDmesg(object):
>> > +    """ An dummy class for dmesg on non unix-like systems
>> > +
>> > +    This implements a dummy version of the LinuxDmesg, and can be used
>> > anytime +    it is not desirable to actually read dmesg, such as
>> > non-posix systems, or +    when the contents of dmesg don't matter.
>> > +
>> > +    """
>> > +    DMESG_COMMAND = []
>> > +
>> > +    def __init__(self):
>> > +        pass
>> > +
>> > +    def update_dmesg(self):
>> > +        """ Dummy version of update_dmesg """
>> > +        pass
>> > +
>> > +    def update_result(self, result):
>> > +        """ Dummy version of update_result """
>> > +        return result
>> > +
>> > +
>> > +class DmesgError(EnvironmentError):
>> > +    pass
>> > +
>> > +
>> > +def get_dmesg(not_dummy=True):
>> > +    """ Return a Dmesg type instance
>> > +
>> > +    Normally this does a system check, and returns the type that proper
>> > for +    your system. However, if Dummy is True then it will always
>> > return a +    DummyDmesg instance.
>> > +
>> > +    """
>> > +    if sys.platform.startswith('linux') and not_dummy:
>> > +        return LinuxDmesg()
>> > +    return DummyDmesg()
>> > --
>> > 1.8.5.3
>> >
>> > _______________________________________________
>> > Piglit mailing list
>> > Piglit at lists.freedesktop.org
>> > http://lists.freedesktop.org/mailman/listinfo/piglit
>
> Is that review for the series?

It's a review for this patch. I believe I also reviewed 3/4 and 4/4
earlier on (and those reviews should still stand). 2/4 uses some fancy
testing framework I'm not familiar with, so I haven't looked at it.
But the impact is also low, so probably fine to commit unreviewed?
Dunno what the policy is.


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