[ltt-dev] Arming only a few markers in LTTng

[ltt-dev] Arming only a few markers in LTTng

[Gaurav Singh]

Hi,

Just a small query on ltt-armall. I tried enabling only a few markers at
runtime instead of running ltt-armall. The trace was successfully collected
but viewing the trace in LTTV is giving a segmentation fault. Has anyone
tried this before?

Regards
Gaurav
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[ltt-dev] Arming only a few markers in LTTng

[Pierre-Marc Fournier]

Hi Gaurav,

Please tell us what tracepoints from the standard ones you tried to
enable. LTTV has some analyses that are pretty tied to some of them and
it might not digest well that some are absent.

Does it work in text dump?
lttv.real -m textDump -t /tmp/your/trace

Does it work in gui when the only loaded plugin is the event viewer?
lttv.real -m lttvwindow -m guievents -t /tmp/your/trace

If so, you might try enabling other views until it segfaults to find the
culprit.

Thanks

pmf


Gaurav Singh wrote:
> Hi,
>  
> Just a small query on ltt-armall. I tried enabling only a few markers at
> runtime instead of running ltt-armall. The trace was successfully
> collected but viewing the trace in LTTV is giving a segmentation fault.
> Has anyone tried this before?
>  
> Regards
> Gaurav
> 
> 
> ------------------------------------------------------------------------
> 
> _______________________________________________
> ltt-dev mailing list
> ltt-dev at lists.casi.polymtl.ca
> http://lists.casi.polymtl.ca/cgi-bin/mailman/listinfo/ltt-dev

[ltt-dev] Arming only a few markers in LTTng

[Mathieu Desnoyers]

* Pierre-Marc Fournier (pierre-marc.fournier at polymtl.ca) wrote:
> Hi Gaurav,
> 
> Please tell us what tracepoints from the standard ones you tried to
> enable. LTTV has some analyses that are pretty tied to some of them and
> it might not digest well that some are absent.
> 
> Does it work in text dump?
> lttv.real -m textDump -t /tmp/your/trace
> 
> Does it work in gui when the only loaded plugin is the event viewer?
> lttv.real -m lttvwindow -m guievents -t /tmp/your/trace
> 
> If so, you might try enabling other views until it segfaults to find the
> culprit.
> 

Hi Gaurav,

LTTV *should* support the fact that probes are missing. If you can,
please compile with :

./configure CFLAGS="-g"
make
make install

and run through gdb

gdb path_to/lttv.real
set args -m textDump -t /tmp/trace
or
set args -m guicontrolflow -t /tmp/trace

So you can report the backtrace (bt full) when it segfaults.

Thanks,

Mathieu

> Thanks
> 
> pmf
> 
> 
> Gaurav Singh wrote:
> > Hi,
> >  
> > Just a small query on ltt-armall. I tried enabling only a few markers at
> > runtime instead of running ltt-armall. The trace was successfully
> > collected but viewing the trace in LTTV is giving a segmentation fault.
> > Has anyone tried this before?
> >  
> > Regards
> > Gaurav
> > 
> > 
> > ------------------------------------------------------------------------
> > 
> > _______________________________________________
> > ltt-dev mailing list
> > ltt-dev at lists.casi.polymtl.ca
> > http://lists.casi.polymtl.ca/cgi-bin/mailman/listinfo/ltt-dev
> 

-- 
Mathieu Desnoyers
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F  BA06 3F25 A8FE 3BAE 9A68

[ltt-dev] Arming only a few markers in LTTng

[Gaurav Singh]

Hi Mathieu, Pierre and others,

Following is a script ltt-arm which I use to arm only few markers for
tracing. Please check if this is the correct implementation.

Usage: ltt-arm -m <names of markers to be armed>

#!/bin/sh
mflag=0
startflag=0
zero=0
        while getopts 'm:h' OPTION
        do
          case $OPTION in
          m)    mflag=1
                if [ $startflag = $zero ]
                then
                        echo Connecting internal_kernel_sched_schedule
                        echo "connect internal_kernel_sched_schedule
scheduler" > /proc/ltt
                        MARKERS=`cat /proc/ltt|grep -v %k|awk '{print
$2}'|sort -u|grep -v ^core_|grep -v ^locking_ |grep -v ^internal_`
                        startflag=1
                fi
                for a in $MARKERS; do if [ $a = $OPTARG ]; then
                echo Connecting $OPTARG
                echo "connect $OPTARG default" > /proc/ltt
                fi;
                done;
                        ;;
          h)    printf "Help \n arguments : \n-m <names of markers seperated
by spaces>\n"
                        ;;
          ?)    printf "error"
                        exit 2
                        ;;
           esac
        done
shift $(($OPTIND - 1))
if [ "$mflag" ]
        then
          for a in $*; do for b in $MARKERS; do if [ $a = $b ]; then echo
Connecting $a; echo "connect $a default" > /proc/ltt;fi; done; done;
        fi

also following is the patch for LTTV to solve the seg fault that I was
getting. Again grateful if you can suggest any changes:

diff -uprN lttv_orig/lttv-0.10.0-pre11-10032008/lttv/lttv/tracecontext.c
lttv-0.10.0-pre11-10032008/lttv/lttv/tracecontext.c
--- lttv_orig/lttv-0.10.0-pre11-10032008/lttv/lttv/tracecontext.c 2007-11-12
10:03:20.000000000 +0530
+++ lttv-0.10.0-pre11-10032008/lttv/lttv/tracecontext.c 2009-02-10
11:44:24.000000000 +0530
@@ -1038,10 +1038,14 @@ skip_marker:
 void lttv_trace_hook_remove_all(GArray **th)
 {
   int i;
+ if((*th)->len!=0)
+ {
   for(i=0; i<(*th)->len; i++) {
     g_ptr_array_free(g_array_index(*th, LttvTraceHook, i).fields, TRUE);
   }
+
   *th = g_array_remove_range(*th, 0, (*th)->len);
+ }
 }

Thanks Pierre and Mathieu
Regards
Gaurav Singh




On Mon, Feb 2, 2009 at 9:40 PM, Mathieu Desnoyers <
compudj at krystal.dyndns.org> wrote:

> * Pierre-Marc Fournier (pierre-marc.fournier at polymtl.ca) wrote:
> > Hi Gaurav,
> >
> > Please tell us what tracepoints from the standard ones you tried to
> > enable. LTTV has some analyses that are pretty tied to some of them and
> > it might not digest well that some are absent.
> >
> > Does it work in text dump?
> > lttv.real -m textDump -t /tmp/your/trace
> >
> > Does it work in gui when the only loaded plugin is the event viewer?
> > lttv.real -m lttvwindow -m guievents -t /tmp/your/trace
> >
> > If so, you might try enabling other views until it segfaults to find the
> > culprit.
> >
>
> Hi Gaurav,
>
> LTTV *should* support the fact that probes are missing. If you can,
> please compile with :
>
> ./configure CFLAGS="-g"
> make
> make install
>
> and run through gdb
>
> gdb path_to/lttv.real
> set args -m textDump -t /tmp/trace
> or
> set args -m guicontrolflow -t /tmp/trace
>
> So you can report the backtrace (bt full) when it segfaults.
>
> Thanks,
>
> Mathieu
>
> > Thanks
> >
> > pmf
> >
> >
> > Gaurav Singh wrote:
> > > Hi,
> > >
> > > Just a small query on ltt-armall. I tried enabling only a few markers
> at
> > > runtime instead of running ltt-armall. The trace was successfully
> > > collected but viewing the trace in LTTV is giving a segmentation fault.
> > > Has anyone tried this before?
> > >
> > > Regards
> > > Gaurav
> > >
> > >
> > >
> ------------------------------------------------------------------------
> > >
> > > _______________________________________________
> > > ltt-dev mailing list
> > > ltt-dev at lists.casi.polymtl.ca
> > > http://lists.casi.polymtl.ca/cgi-bin/mailman/listinfo/ltt-dev
> >
>
> --
> Mathieu Desnoyers
> OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F  BA06 3F25 A8FE 3BAE 9A68
>
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[ltt-dev] Arming only a few markers in LTTng

[Gaurav Singh]

Hi Mathieu, Pierre, others,

As Mathieu suggested GDB pinpointed the segfault to
lttv_trace_hook_remove_all function in tracecontext.c - the patch given
before has been tested for traces with all markers enabled and traces with a
few mrakers enabled. Pierre - I could not find any dependencies to hinder my
analysis.

Thanks again :)
Regards
Gaurav

On Tue, Feb 10, 2009 at 12:01 PM, Gaurav Singh <gausinghnsit at gmail.com>wrote:

> Hi Mathieu, Pierre and others,
>
> Following is a script ltt-arm which I use to arm only few markers for
> tracing. Please check if this is the correct implementation.
>
> Usage: ltt-arm -m <names of markers to be armed>
>
> #!/bin/sh
> mflag=0
> startflag=0
> zero=0
>         while getopts 'm:h' OPTION
>         do
>           case $OPTION in
>           m)    mflag=1
>                 if [ $startflag = $zero ]
>                 then
>                         echo Connecting internal_kernel_sched_schedule
>                         echo "connect internal_kernel_sched_schedule
> scheduler" > /proc/ltt
>                         MARKERS=`cat /proc/ltt|grep -v %k|awk '{print
> $2}'|sort -u|grep -v ^core_|grep -v ^locking_ |grep -v ^internal_`
>                         startflag=1
>                 fi
>                 for a in $MARKERS; do if [ $a = $OPTARG ]; then
>                 echo Connecting $OPTARG
>                 echo "connect $OPTARG default" > /proc/ltt
>                 fi;
>                 done;
>                         ;;
>           h)    printf "Help \n arguments : \n-m <names of markers
> seperated by spaces>\n"
>                         ;;
>           ?)    printf "error"
>                         exit 2
>                         ;;
>            esac
>         done
> shift $(($OPTIND - 1))
> if [ "$mflag" ]
>         then
>           for a in $*; do for b in $MARKERS; do if [ $a = $b ]; then echo
> Connecting $a; echo "connect $a default" > /proc/ltt;fi; done; done;
>         fi
>
> also following is the patch for LTTV to solve the seg fault that I was
> getting. Again grateful if you can suggest any changes:
>
> diff -uprN lttv_orig/lttv-0.10.0-pre11-10032008/lttv/lttv/tracecontext.c
> lttv-0.10.0-pre11-10032008/lttv/lttv/tracecontext.c
> ---
> lttv_orig/lttv-0.10.0-pre11-10032008/lttv/lttv/tracecontext.c 2007-11-12
> 10:03:20.000000000 +0530
> +++ lttv-0.10.0-pre11-10032008/lttv/lttv/tracecontext.c 2009-02-10
> 11:44:24.000000000 +0530
> @@ -1038,10 +1038,14 @@ skip_marker:
>  void lttv_trace_hook_remove_all(GArray **th)
>  {
>    int i;
> + if((*th)->len!=0)
> + {
>    for(i=0; i<(*th)->len; i++) {
>      g_ptr_array_free(g_array_index(*th, LttvTraceHook, i).fields, TRUE);
>    }
> +
>    *th = g_array_remove_range(*th, 0, (*th)->len);
> + }
>  }
>
> Thanks Pierre and Mathieu
> Regards
> Gaurav Singh
>
>
>
>
> On Mon, Feb 2, 2009 at 9:40 PM, Mathieu Desnoyers <
> compudj at krystal.dyndns.org> wrote:
>
>> * Pierre-Marc Fournier (pierre-marc.fournier at polymtl.ca) wrote:
>> > Hi Gaurav,
>> >
>> > Please tell us what tracepoints from the standard ones you tried to
>> > enable. LTTV has some analyses that are pretty tied to some of them and
>> > it might not digest well that some are absent.
>> >
>> > Does it work in text dump?
>> > lttv.real -m textDump -t /tmp/your/trace
>> >
>> > Does it work in gui when the only loaded plugin is the event viewer?
>> > lttv.real -m lttvwindow -m guievents -t /tmp/your/trace
>> >
>> > If so, you might try enabling other views until it segfaults to find the
>> > culprit.
>> >
>>
>> Hi Gaurav,
>>
>> LTTV *should* support the fact that probes are missing. If you can,
>> please compile with :
>>
>> ./configure CFLAGS="-g"
>> make
>> make install
>>
>> and run through gdb
>>
>> gdb path_to/lttv.real
>> set args -m textDump -t /tmp/trace
>> or
>> set args -m guicontrolflow -t /tmp/trace
>>
>> So you can report the backtrace (bt full) when it segfaults.
>>
>> Thanks,
>>
>> Mathieu
>>
>> > Thanks
>> >
>> > pmf
>> >
>> >
>> > Gaurav Singh wrote:
>> > > Hi,
>> > >
>> > > Just a small query on ltt-armall. I tried enabling only a few markers
>> at
>> > > runtime instead of running ltt-armall. The trace was successfully
>> > > collected but viewing the trace in LTTV is giving a segmentation
>> fault.
>> > > Has anyone tried this before?
>> > >
>> > > Regards
>> > > Gaurav
>> > >
>> > >
>> > >
>> ------------------------------------------------------------------------
>> > >
>> > > _______________________________________________
>> > > ltt-dev mailing list
>> > > ltt-dev at lists.casi.polymtl.ca
>> > > http://lists.casi.polymtl.ca/cgi-bin/mailman/listinfo/ltt-dev
>> >
>>
>> --
>> Mathieu Desnoyers
>> OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F  BA06 3F25 A8FE 3BAE
>> 9A68
>>
>
>
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[ltt-dev] Arming only a few markers in LTTng

[Mathieu Desnoyers]

* Gaurav Singh (gausinghnsit at gmail.com) wrote:
> Hi Mathieu, Pierre and others,
> 
> Following is a script ltt-arm which I use to arm only few markers for
> tracing. Please check if this is the correct implementation.
> 
> Usage: ltt-arm -m <names of markers to be armed>
> 
> #!/bin/sh
> mflag=0
> startflag=0
> zero=0
>         while getopts 'm:h' OPTION
>         do
>           case $OPTION in
>           m)    mflag=1
>                 if [ $startflag = $zero ]
>                 then
>                         echo Connecting internal_kernel_sched_schedule
>                         echo "connect internal_kernel_sched_schedule
> scheduler" > /proc/ltt
>                         MARKERS=`cat /proc/ltt|grep -v %k|awk '{print
> $2}'|sort -u|grep -v ^core_|grep -v ^locking_ |grep -v ^internal_`
>                         startflag=1
>                 fi
>                 for a in $MARKERS; do if [ $a = $OPTARG ]; then
>                 echo Connecting $OPTARG
>                 echo "connect $OPTARG default" > /proc/ltt
>                 fi;
>                 done;
>                         ;;
>           h)    printf "Help \n arguments : \n-m <names of markers seperated
> by spaces>\n"
>                         ;;
>           ?)    printf "error"
>                         exit 2
>                         ;;
>            esac
>         done
> shift $(($OPTIND - 1))
> if [ "$mflag" ]
>         then
>           for a in $*; do for b in $MARKERS; do if [ $a = $b ]; then echo
> Connecting $a; echo "connect $a default" > /proc/ltt;fi; done; done;
>         fi
> 

Hrm, given we now have the debugfs interface, I am not sure it's needed
anymore.

> also following is the patch for LTTV to solve the seg fault that I was
> getting. Again grateful if you can suggest any changes:
> 
> diff -uprN lttv_orig/lttv-0.10.0-pre11-10032008/lttv/lttv/tracecontext.c
> lttv-0.10.0-pre11-10032008/lttv/lttv/tracecontext.c
> --- lttv_orig/lttv-0.10.0-pre11-10032008/lttv/lttv/tracecontext.c 2007-11-12
> 10:03:20.000000000 +0530
> +++ lttv-0.10.0-pre11-10032008/lttv/lttv/tracecontext.c 2009-02-10
> 11:44:24.000000000 +0530
> @@ -1038,10 +1038,14 @@ skip_marker:
>  void lttv_trace_hook_remove_all(GArray **th)
>  {
>    int i;
> + if((*th)->len!=0)
> + {
>    for(i=0; i<(*th)->len; i++) {
>      g_ptr_array_free(g_array_index(*th, LttvTraceHook, i).fields, TRUE);
>    }
> +
>    *th = g_array_remove_range(*th, 0, (*th)->len);
> + }
>  }

It's already fixed by commit

r2929 | pmf | 2008-05-30 11:15:26 -0400 (Fri, 30 May 2008) | 2 lines

lttv: don't crash on empty trace

Therefore current LTTV should not be affected.

Thanks,

Mathieu

> 
> Thanks Pierre and Mathieu
> Regards
> Gaurav Singh
> 
> 
> 
> 
> On Mon, Feb 2, 2009 at 9:40 PM, Mathieu Desnoyers <
> compudj at krystal.dyndns.org> wrote:
> 
> > * Pierre-Marc Fournier (pierre-marc.fournier at polymtl.ca) wrote:
> > > Hi Gaurav,
> > >
> > > Please tell us what tracepoints from the standard ones you tried to
> > > enable. LTTV has some analyses that are pretty tied to some of them and
> > > it might not digest well that some are absent.
> > >
> > > Does it work in text dump?
> > > lttv.real -m textDump -t /tmp/your/trace
> > >
> > > Does it work in gui when the only loaded plugin is the event viewer?
> > > lttv.real -m lttvwindow -m guievents -t /tmp/your/trace
> > >
> > > If so, you might try enabling other views until it segfaults to find the
> > > culprit.
> > >
> >
> > Hi Gaurav,
> >
> > LTTV *should* support the fact that probes are missing. If you can,
> > please compile with :
> >
> > ./configure CFLAGS="-g"
> > make
> > make install
> >
> > and run through gdb
> >
> > gdb path_to/lttv.real
> > set args -m textDump -t /tmp/trace
> > or
> > set args -m guicontrolflow -t /tmp/trace
> >
> > So you can report the backtrace (bt full) when it segfaults.
> >
> > Thanks,
> >
> > Mathieu
> >
> > > Thanks
> > >
> > > pmf
> > >
> > >
> > > Gaurav Singh wrote:
> > > > Hi,
> > > >
> > > > Just a small query on ltt-armall. I tried enabling only a few markers
> > at
> > > > runtime instead of running ltt-armall. The trace was successfully
> > > > collected but viewing the trace in LTTV is giving a segmentation fault.
> > > > Has anyone tried this before?
> > > >
> > > > Regards
> > > > Gaurav
> > > >
> > > >
> > > >
> > ------------------------------------------------------------------------
> > > >
> > > > _______________________________________________
> > > > ltt-dev mailing list
> > > > ltt-dev at lists.casi.polymtl.ca
> > > > http://lists.casi.polymtl.ca/cgi-bin/mailman/listinfo/ltt-dev
> > >
> >
> > --
> > Mathieu Desnoyers
> > OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F  BA06 3F25 A8FE 3BAE 9A68
> >

-- 
Mathieu Desnoyers
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F  BA06 3F25 A8FE 3BAE 9A68