[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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