TSV and DRecord on Solaris

Question

Hello,
Currently I am trying to monitor my Java RealTime application that runs with Sun Java RTS 2.2 on Solaris 10, using the TSV tool (that comes with Java RTS 2.2) and the DTrace utility.
The problem that I have is, that the "dmonitor" script (available under the <TSV_InstallDir>/bin directory), recommended to be used by the TSV documentation, will not work since the sched:::change-pri probe does not work. Please note that I have tried to use the drecord script as well, which also uses this DTrace probe, and it does not work either. (Please note that the dmonitor script only comes with the TSV delivered with Java RTS 2.2).
The message I get is : “... in action list: args[ ] may not be referenced because probe description sched:::change-pri matches an unstable set of probes”.
I have set the –x amin to the lowest in the dmonitor script (-x amin=Private/Private/Unknown) but the error stays.
Maybe also important to mention is, that I am starting the "dtrace" tool using "pfexec", like "pfexec dtrace ....". I have adapted the drecord and dmonitor tools for that.
For completeness, here's the dtrace script used by the dmonitor:
script='
BEGIN
   timeout = $1;
profile:::tick-1s
  this->count++;
profile-1s
/this->count >= timeout/
  exit(0);
sched:::on-cpu
/pid == $target && self->on_cpu == 0/
    printf("%d on-cpu %d %d %d\n",timestamp,tid,cpu,curthread->t_pri);
    self->on_cpu = 1;
sched:::off-cpu
/pid == $target && self->on_cpu == 1/
    printf("%d off-cpu %d \n",timestamp,tid);
    self->on_cpu = 0;
sched:::change-pri
/pid == $target/
    printf("%d change-pri %d %d\n",timestamp,args[0]->pr_lwpid,args[2]);
jrts$target:::thread-set-name
  printf("%d set-name %d %s\n",timestamp,(int)arg0,copyinstr(arg1,arg2));
jrts$target:::thread-start
  printf("%d set-name %d %s\n",timestamp,(int)arg0,copyinstr(arg4,arg5));
jrts$target:::user-event
    printf("%d user-event %d %d %d %s\n",timestamp,tid,cpu,curthread->t_pri,copyinstr(arg0,arg1));
'Once I remove the sched:::change-pri probe completelly, the rest works.
Thank you a lot in advance for any hints ;)
Best regards,
Sergiu Burian

Answer 1

Sergiu,
Thanks for the detailed post (my own copy of TSV was downrev and missing the very useful dmonitor script).
This is very puzzling. The error message means that either:
a) the probe did not exist when Dtrace was started; or
b) the clause matches more than one probe
and in both cases the argument array can not be typed so you can not use arg[n] syntax to access them.
There are a couple of possible work-arounds:
1. Be more specific with the probe. Trying editing the script to use sched:RT:rt_change_priority:change-pri
Of course if you want all the priority-change events then you need to produce additional clauses for the TS class as well. The full list of probes seems to be:
  986      sched           genunix                 thread_change_pri change-pri
1020      sched                TS                ts_change_priority change-pri
1021      sched                TS                          ts_yield change-pri
1022      sched                TS                         ts_wakeup change-pri
1023      sched                TS                        ts_trapret change-pri
1024      sched                TS                          ts_sleep change-pri
1025      sched                TS                         ts_setrun change-pri
1026      sched                TS                        ts_preempt change-pri
2192      sched                FX                fx_change_priority change-pri
2193      sched                FX                          fx_yield change-pri
2194      sched                FX                         fx_wakeup change-pri
2195      sched                FX                        fx_preempt change-pri
2214      sched                RT                rt_change_priority change-pri2. Change the script to use arg0, arg1, arg2 rather than arg[0], arg[1], arg[2] (this might entail some type casting - sorry not really my area)
I will see if I can find out anything which may have changed in this area.
Thanks,
David Holmes