covoar SIGKILL Investigation
Joel Sherrill
joel at rtems.org
Fri Aug 31 19:05:39 UTC 2018
On Fri, Aug 31, 2018 at 1:42 PM Vijay Kumar Banerjee <
vijaykumar9597 at gmail.com> wrote:
>
>
>
> On Sat, 1 Sep 2018 at 00:01, Joel Sherrill <joel at rtems.org> wrote:
>
>>
>>
>> On Fri, Aug 31, 2018, 12:44 PM Vijay Kumar Banerjee <
>> vijaykumar9597 at gmail.com> wrote:
>>
>>> Hello,
>>> I have listed all the specific exes for which covoar fails.
>>> I have observed that covoar fails only for some specific exe for some
>>> symbol-sets,
>>> this was the reason for covoar not completing successfully. If we
>>> exclude these exe,
>>> covoar finishes successfully for the whole testsuites. So the prolem has
>>> become more
>>> specific now, we'll have to investigate for only these exe.
>>>
>>> Here's the list of all the symbol-sets that were failing, along with the
>>> exe files that made them
>>> trip.
>>>
>>> -----------------------
>>> posix ----
>>> sptests/spmutex01.exe
>>> fstests/fsclose01.exe
>>>
>>> sapi ----
>>> sptests/spversion01.exe
>>>
>>> librfs ----
>>> fstests/mrfs_fserror.exe
>>> fstests/mrfs_fsrdwr.exe
>>> (all fstests/mrfs_*.exe fails)
>>> fstests/fsrofs01.exe
>>> libtests/flashdisk01.exe
>>>
>>> libdevnull ----
>>> sptests/sp21.exe
>>> psxtests/psxmmap01.exe
>>> tmtests/tm20.exe
>>>
>>> libblock ----
>>> fstests/fsbdpart01.exe
>>> ---------------------
>>>
>>
>> Thanks.
>>
>> Have you had a chance to try get with catch throw?
>>
> I'm trying it now with posix and fsclose01.exe, here's what I see.
>
I think we need Chris to wake up and give us some feedback. The throw is
using
rld::error.
My guess is that something in those executables is not making rld happy.
#4 is the line of the following line of code in covoar.cc:
// Load the objdump for the symbols in this executable.
objdumpProcessor->load( exe, objdumpFile, err );
}
That's the loop loading the executables. Something in each of these exes
is not making the underlying ELF/DWARF code happy.
Hopefully Chris will wake up fresh on a nice Australian Saturday and
have an answer. :)
>
> ------------------------------------
> Catchpoint 1 (exception thrown), 0x00007ffff7ad7f51 in
> __cxxabiv1::__cxa_throw (obj=obj at entry=0x832c80,
> tinfo=tinfo at entry=0x488a70 <typeinfo for rld::error>, dest=dest at entry=0x40f980
> <rld::error::~error()>)
> at ../../../../libstdc++-v3/libsupc++/eh_throw.cc:78
> 78 PROBE2 (throw, obj, tinfo);
> (gdb) bt
> #0 0x00007ffff7ad7f51 in __cxxabiv1::__cxa_throw (obj=obj at entry=0x832c80,
> tinfo=tinfo at entry=0x488a70 <typeinfo for rld::error>,
> dest=dest at entry=0x40f980 <rld::error::~error()>) at
> ../../../../libstdc++-v3/libsupc++/eh_throw.cc:78
> #1 0x0000000000405926 in Coverage::ExecutableInfo::findCoverageMap
> (this=<optimized out>, symbolName="wait")
> #2 0x000000000041bc1d in
> Coverage::finalizeSymbol(Coverage::ExecutableInfo*,
> std::__cxx11::basic_string<char, std::char_traits<char>,
> std::allocator<char> >&,
> std::__cxx11::list<Coverage::ObjdumpProcessor::objdumpLine_t,
> std::allocator<Coverage::ObjdumpProcessor::objdumpLine_t> >)
> () at ../tester/covoar/ObjdumpProcessor.cc:35
>
#3 0x000000000041c9e6 in
> Coverage::ObjdumpProcessor::load(Coverage::ExecutableInfo*,
> rld::process::tempfile&, rld::process::tempfile&) ()
> at /usr/include/c++/8/new:169
> #4 0x000000000040e058 in covoar(int, char**) () at
> ../tester/covoar/covoar.cc:381
> #5 0x000000000040bacc in main () at ../tester/covoar/covoar.cc:563
> #6 0x00007ffff70fd1bb in __libc_start_main (main=0x40b9b0 <main>,
> argc=11, argv=0x7fffffffd4b8, init=<optimized out>, fini=<optimized out>,
> rtld_fini=<optimized out>, stack_end=0x7fffffffd4a8) at
> ../csu/libc-start.c:308
> #7 0x000000000040c32a in _start () at ../tester/covoar/covoar.cc:593
>
> ------------------------------------
>
>>
>>>
>>> On Wed, 22 Aug 2018 at 21:11, Vijay Kumar Banerjee <
>>> vijaykumar9597 at gmail.com> wrote:
>>>
>>>> I will send the attachment offlist as it's too big for the list.
>>>> On Wed, 22 Aug 2018 at 21:07, Vijay Kumar Banerjee <
>>>> vijaykumar9597 at gmail.com> wrote:
>>>>
>>>>> The coverage for whole testsuite completed successfully,
>>>>> I have attached the zip file here and also included the js and css
>>>>> files in it.
>>>>>
>>>>> coverage didn't complete for the following symbol-set libraries and
>>>>> was returning,
>>>>> covoar error 10
>>>>>
>>>>> * libsapi.a
>>>>> * libposix.a
>>>>> * librfs.a
>>>>> * libcsupport.a
>>>>> * libdevnull.a
>>>>> * libblock.a
>>>>>
>>>>>
>>>>> On Wed, 22 Aug 2018 at 10:22, Chris Johns <chrisj at rtems.org> wrote:
>>>>>
>>>>>> On 22/08/2018 14:41, Joel Sherrill wrote:
>>>>>> > On Tue, Aug 21, 2018, 10:26 PM Chris Johns <chrisj at rtems.org
>>>>>> > <mailto:chrisj at rtems.org>> wrote:
>>>>>> >
>>>>>> > On 22/08/2018 09:29, Joel Sherrill wrote:
>>>>>> > > On Tue, Aug 21, 2018, 4:05 PM Vijay Kumar Banerjee
>>>>>> > <vijaykumar9597 at gmail.com <mailto:vijaykumar9597 at gmail.com>
>>>>>> > > <mailto:vijaykumar9597 at gmail.com <mailto:
>>>>>> vijaykumar9597 at gmail.com>>> wrote:
>>>>>> > > On Wed, 22 Aug 2018 at 01:55, Joel Sherrill <
>>>>>> joel at rtems.org
>>>>>> > <mailto:joel at rtems.org>
>>>>>> > > <mailto:joel at rtems.org <mailto:joel at rtems.org>>> wrote:
>>>>>> > >
>>>>>> > > How long is covoar taking for the entire set?
>>>>>> > >
>>>>>> > > It works great. this is what `time` says
>>>>>> > > --------
>>>>>> > > real17m49.887s
>>>>>> > > user14m25.620s
>>>>>> > > sys0m37.847s
>>>>>> > > --------
>>>>>> > >
>>>>>> > > What speed and type of processor do you have?
>>>>>> > >
>>>>>> >
>>>>>> > The program is single threaded so the preprocessing of each
>>>>>> executable is
>>>>>> > sequential. Memory usage is reasonable so there is no swapping.
>>>>>> >
>>>>>> > Running covoar from the command line on a box with:
>>>>>> >
>>>>>> > hw.machine: amd64
>>>>>> > hw.model: Intel(R) Core(TM) i7-6900K CPU @ 3.20GHz
>>>>>> > hw.ncpu: 16
>>>>>> > hw.machine_arch: amd64
>>>>>> >
>>>>>> > plus 32G of memory has a time of:
>>>>>> >
>>>>>> > 366.32 real 324.97 user 41.33 sys
>>>>>> >
>>>>>> > The approximate time break down is:
>>>>>> >
>>>>>> > ELF/DWARF loading : 110s (1m50s)
>>>>>> > Objdump : 176s (2m56s)
>>>>>> > Processing : 80s (1m20s)
>>>>>> >
>>>>>> >
>>>>>> > I don't mind this execution time for the near future. It is far
>>>>>> from obscene
>>>>>> > after building and running 600 tests.
>>>>>>
>>>>>> Yeah, there are other things we need to do first.
>>>>>>
>>>>>> > The DWARF loading is not optimised and I load all source line
>>>>>> to address maps
>>>>>> > and all functions rather that selectively scanning for specific
>>>>>> names at the
>>>>>> > DWARF level. It is not clear to me scanning would be better or
>>>>>> faster.
>>>>>> >
>>>>>> > I doubt it is worth the effort. There should be few symbols in an
>>>>>> exe we don't
>>>>>> > care about. Especially once we start to worry about libc and libm.
>>>>>>
>>>>>> Yeah, this is what I thought at the start.
>>>>>>
>>>>>> > My hope
>>>>>> > is moving to Capstone would help lower or remove the objdump
>>>>>> overhead. Then
>>>>>> > there is threading for the loading.
>>>>>> >
>>>>>> > > I don't recall it taking near this long in the past. I used
>>>>>> to run it as
>>>>>> > part of
>>>>>> > > development.
>>>>>> >
>>>>>> > The objdump processing is simpler than before so I suspect the
>>>>>> time would have
>>>>>> > been at least 4 minutes.
>>>>>> >
>>>>>> > > But we may have more tests and the code has changed.
>>>>>> >
>>>>>> > I think having more tests is the dominant factor.
>>>>>> >
>>>>>> > > Reading dwarf
>>>>>> > > with the file open/closes, etc just may be more expensive
>>>>>> than parsing the
>>>>>> > text
>>>>>> > > files.
>>>>>> >
>>>>>> > The reading DWARF is a cost and at the moment it is not
>>>>>> optimised but it is only
>>>>>> > a cost because we still parse the objdump data. I think opening
>>>>>> and closing
>>>>>> > files is not a factor.
>>>>>> >
>>>>>> > The parsing the objdump is the largest component of time. Maybe
>>>>>> using Capstone
>>>>>> > with the ELF files will help.
>>>>>> >
>>>>>> > > But it is more accurate and lays the groundwork.for more
>>>>>> types of analysis.
>>>>>> >
>>>>>> > Yes and think this is important.
>>>>>> >
>>>>>> > +1
>>>>>> >
>>>>>> > > Eventually we will have to profile this code. Whatever is
>>>>>> costly is done for
>>>>>> > > each exe so there is a multiplier.
>>>>>> > >
>>>>>> > > I suspect this code would parallelize reading info from the
>>>>>> exes fairly well.
>>>>>> >
>>>>>> > Agreed.
>>>>>> >
>>>>>> > Might be a good case for C++11 threads if one of the thread
>>>>>> container classes is
>>>>>> > a nice pool.
>>>>>>
>>>>>> Good idea. I think we need to look at some of the global object
>>>>>> pointers before
>>>>>> we head down this path.
>>>>>>
>>>>>> > And we might have some locking to account for in core data
>>>>>> structures. Are STL
>>>>>> > container instances thread safe?
>>>>>>
>>>>>> We need to manage all locking.
>>>>>>
>>>>>> > But an addition after feature stable relative to old output plus
>>>>>> Capstone.
>>>>>>
>>>>>> Agreed.
>>>>>>
>>>>>> > > Merging the info and generating the reports not well due to
>>>>>> data contention.
>>>>>> >
>>>>>> > Yes.
>>>>>> >
>>>>>> > > But optimizing too early and the wrong way is not smart.
>>>>>> >
>>>>>> > Yes. We need Capstone to be added before this can happen.
>>>>>> >
>>>>>> > +1
>>>>>> >
>>>>>> > I would also like to see gcov support but that will not be a factor
>>>>>> in the
>>>>>> > performance we have. It will add reading a lot more files (gcno)
>>>>>> and writing a
>>>>>> > lot of gcda at the end. Again more important to be right than fast
>>>>>> at first. And
>>>>>> > completely an addition.
>>>>>>
>>>>>> Agreed.
>>>>>>
>>>>>> Chris
>>>>>>
>>>>>
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