Re: [Crash-utility] Extensions: Dump log buffer of Intel Processor Trace

----- Original Message ----- > On 2016/01/06 12:32, Dave Anderson wrote: >> >> >> ----- Original Message ----- >>> On 2016/01/06 1:42, Dave Anderson wrote: >>>> >>>> >>>> ----- Original Message ----- >>>>> >>>>> >>>>> ----- Original Message ----- >>>>>> Hi Dave, >>>>>> >>>>>> The attached files are extension module to dump log buffer of Intel >>>>>> Processor Trace from vmcore. Please consider placing this in the >>>>>> extensions page. >>>>>> >>>>>> [Overview of PT] >>>>>> PT(Processor Trace) is a new feature of Intel CPU "Broadwell", it >>>>>> captures information about program execution flow.[1] >>>>>> >>>>>> Once Intel PT is enabled, the events which change program flow, like >>>>>> branch instructions, exceptions, interruptions, traps and so on are >>>>>> logged in the memory. This is very useful for debugging because we can >>>>>> know the detailed behavior of software. >>>>>> >>>>>> >>>>>> [About extension] >>>>>> This extension retrieves log buff of PT from vmcore and saves it as a >>>>>> file. 'ptdump' command can be used once this extension is loaded. >>>>>> >>>>>> crash> extend extensions/ptdump.so >>>>>> ./extensions/ptdump.so: shared object loaded >>>>>> crash> ptdump output_dir >>>>>> [0] buffer dump: dump.0 >>>>>> [0] packet decode: decode.0 >>>>>> [1] buffer dump: dump.1 >>>>>> [1] packet decode: decode.1 >>>>>> (snipped) >>>>>> >>>>>> In this case, output_dir directory is created, and then dump.N and >>>>>> decode.N files are created in the directory for each cpus(N is cpu >>>>>> number). >>>>>> >>>>>> dump.N: raw data of PT >>>>>> decode.N: result of PT packet decoder >>>>>> >>>>>> dump.N is binary data and it is not human readable. decode.N is >>>>>> generated by fastdecode[2], which is PT packet dumper created by Andi >>>>>> Kleen. It's useful for checking what kinds of packets are included in >>>>>> dump.N. I'll update extension using PT library(libipt[3]) to generate >>>>>> more useful file for investigation. >>>>>> >>>>>> [Build extension] >>>>>> To build the module from the top-level crash-<version> directory, >>>>>> enter: >>>>>> >>>>>> $ tar xvf ptdump-1.0.0.tar.gz >>>>>> $ mv ptdump-1.0.0/* extensions >>>>>> $ make extensions >>>>>> >>>>>> [1] https://software.intel.com/en-us/blogs/2013/09/18/processor-tracing >>>>>> [2] https://github.com/andikleen/simple-pt >>>>>> [3] https://github.com/01org/processor-trace >>>>>> >>>>>> Thanks, >>>>>> Takao Indoh >>>>> >>>>> Hi Takao, >>>>> >>>>> I certainly can add this to the extensions subdirectory. However >>>>> I do have a couple suggestions with respect to the build procedure: >>>>> >>>>> $ tar xvf $dl/ptdump-1.0.0.tar.gz >>>>> ptdump-1.0.0/ >>>>> ptdump-1.0.0/fastdecode.c >>>>> ptdump-1.0.0/map.c >>>>> ptdump-1.0.0/map.h >>>>> ptdump-1.0.0/ptdump.c >>>>> ptdump-1.0.0/ptdump.mk >>>>> $ mv ptdump-1.0.0/* extensions >>>>> $ make extensions >>>>> gcc -Wall -g -nostartfiles -shared -rdynamic -o fastdecode.so >>>>> fastdecode.c >>>>> -fPIC -DX86_64 -DLZO -DSNAPPY -DGDB_7_6 >>>>> gcc -DLZO -DSNAPPY -Wall -I.. -fPIC -DX86_64 -c -o ptdump.o >>>>> ptdump.c >>>>> gcc -DLZO -DSNAPPY -Wall -I.. -fPIC -DX86_64 -c -o fastdecode.o >>>>> fastdecode.c >>>>> gcc -DLZO -DSNAPPY -Wall -I.. -fPIC -DX86_64 -c -o map.o map.c >>>>> gcc -Wall -g -shared -rdynamic -o map.so map.c -fPIC -DX86_64 -DLZO >>>>> -DSNAPPY -DGDB_7_6 >>>>> $ ls -ltr extensions/*.so >>>>> -rwxrwxr-x 1 anderson anderson 17613 Jan 5 10:51 >>>>> extensions/echo.so* >>>>> -rwxrwxr-x 1 anderson anderson 851633 Jan 5 10:51 >>>>> extensions/eppic.so* >>>>> -rwxrwxr-x 1 anderson anderson 100465 Jan 5 10:51 >>>>> extensions/trace.so* >>>>> -rwxrwxr-x 1 anderson anderson 112373 Jan 5 10:51 >>>>> extensions/dminfo.so* >>>>> -rwxrwxr-x 1 anderson anderson 42358 Jan 5 10:51 >>>>> extensions/snap.so* >>>>> -rwxrwxr-x 1 anderson anderson 15539 Jan 5 10:57 >>>>> extensions/fastdecode.so* >>>>> -rwxrwxr-x 1 anderson anderson 21136 Jan 5 10:57 >>>>> extensions/ptdump.so* >>>>> -rwxrwxr-x 1 anderson anderson 14880 Jan 5 10:57 >>>>> extensions/map.so* >>>>> $ >>>>> >>>>> The build procedure shows the creation of the "map.so" and >>>>> "fastdecode.so" >>>>> shared objects, but does not show the creation of "ptdump.so", which is >>>>> the >>>>> only object that actually gets loaded into a crash session, correct? >>>>> That build line gets hidden because of the "@if" clause: >>>>> >>>>> @if [ $(ARCH) = "UNSUPPORTED" ]; then \ >>>>> echo "ptdump: architecture not supported"; \ >>>>> else \ >>>>> gcc $(CFLAGS) $(TARGET_CFLAGS) $(COMMON_CFLAGS) >>>>> -nostartfiles >>>>> -shared -rdynamic -o $@ $^ ; \ >>>>> fi; >>>>> >>>>> Can you fix that so that a user can actually see the build of ptdump.so? >>> >>> Ok, I'll fix it. >>> >>> >>>>> Also, unlike the other extension modules, the ptdump files and build >>>>> procedure clutter up the extensions subdirectory. Since you do >>>>> not have a single ptdump.mk and ptdump.c file, would it be possible >>>>> for you to do the same kind of thing that the "eppic" module does, >>>>> where there would be an extensions/ptdump.mk file, which would reference >>>>> the sources in a "ptdump" subdirectory where all of the files can be >>>>> cleanly kept in one place? >>>>> >>>>> Thanks, >>>>> Dave >>>> >>>> >>>> Hi Takao, >>>> >>>> Can you explain what fastdecode.so and map.so are used for? >>>> >>>> crash> extend ptdump.so >>>> ./extensions/ptdump.so: shared object loaded >>>> crash> extend fastdecode.so >>>> extend: ./extensions/fastdecode.so: no commands registered: shared >>>> object unloaded >>>> crash> extend map.so >>>> extend: ./extensions/map.so: no commands registered: shared object >>>> unloaded >>>> crash> >>>> >>>> I see fastdecode.o and map.o being included in the ptdump.so compile >>>> line, >>>> but >>>> don't see where fastdecode.so and map.so fit into the picture? >>> >>> fastdecode.so and map.so is not generated. Everything is included in >>> ptdump.so. > > I mean, fastdecode.so and map.so was created by mistake. They are not > needed. This bug is fixed in new version. > >>> >>> I'll change ptdump.mk like this so that unnecessary *.o file is not >>> generated. >>> >>> gcc -Wall -I. -fPIC -DX86_64 -nostartfiles -shared -rdynamic \ >>> -o ptdump.so *.c >>> >>> >>>> >>>> In any case, to clarify my request again, after installation, there >>>> should >>>> be >>>> these files: >>>> >>>> extensions/ptdump.mk >>>> extensions/ptdump/ptdump.c >>>> extensions/ptdump/fastdecode.c >>>> extensions/ptdump/map.c >>>> extensions/ptdump/map.h >>>> >>>> And after the build: >>>> >>>> extensions/ptdump.so >>>> >>>> All of the other .o and .so files should only exist in the >>>> extensions/ptdump >>>> subdirectory. >>> >>> I see, I'll fix them and post updated version soon. >>> I have one question. >>> >>>> extensions/ptdump.mk >>>> extensions/ptdump/ptdump.c >>> >>> ptdump.c should be also placed in extensions/ptdump? >>> In the case of eppic, the files seems to be placed like this: >>> >>> extensions/eppic.mk >>> extensions/eppic.c >>> extensions/eppic/* >>> >>> Therefore if I should do in the same manner, the files should be like >>> this? >>> >>> extensions/ptdump.mk >>> extensions/ptdump.c >>> extensions/ptdump/fastdecode.c >>> extensions/ptdump/map.c >>> extensions/ptdump/map.h >> >> The extensions/eppic.c file is only there so that the extensions/Makefile >> will initiate >> the build of eppic.mk: >> >> $ cat extensions/eppic.c >> /* >> Place holder for proper working of the extension Makefile. >> Eppic crash application file is in eppic/applications/crash/eppic.c >> */ >> $ >> >> But you can put your actual ptdump.c file in the extensions subdirectory if >> you'd like. > > I noticed that ptdump.so was not built if all *.c files are in > extensions/ptdump directory. See extensions/Makefile for details. > > So, I place files like this. > > extensions/ptdump.mk > extensions/ptdump.c > extensions/ptdump/fastdecode.c > extensions/ptdump/map.c > extensions/ptdump/map.h > > I attach new version. > > Thanks, > Takao Indoh > Hi Takao, Nicely done! The module has been added to the extensions page: http://people.redhat.com/anderson/extensions.html#PTDUMP