Re: [ltt-dev] (forw) [chris.meyers.fsu@gmail.com: Re: ltt channel thread safe?]

[David Goulet]

Incoming patch.

Cheers
David

On 10-09-09 12:40 PM, Mathieu Desnoyers wrote:

* Pierre-Marc Fournier (pierre-marc.fourn...@polymtl.ca) wrote:

On 08/27/2010 01:01 PM, Mathieu Desnoyers wrote:

* Fu Juntang(David) (juntang...@windriver.com) wrote:

Hi,Mathieu:
    has the issue any update?

    please see my test case and the trace logs(in the attachment), from
   the trace log,we can see we can only see the trace datas from cpu_0:
    ust.myevent: 18161.506516049
(/home/Large_Space/Part_B/LogStore/LTTngLog_wrlinux-4.0/UST/UST_Logs/multi-thread/david-desktop-20100811163524864824113/11520_5504068123890634635/ust_0),
 0, 0, , , 0, 0x0, MODE_UNKNOWN { firstthread = 2 }
ust.myevent: 18163.506594856
(/home/Large_Space/Part_B/LogStore/LTTngLog_wrlinux-4.0/UST/UST_Logs/multi-thread/david-desktop-20100811163524864824113/11520_5504068123890634635/ust_0),
 0, 0, , , 0, 0x0, MODE_UNKNOWN { firstthread = 3 }
ust.myevent: 18165.506667869
(/home/Large_Space/Part_B/LogStore/LTTngLog_wrlinux-4.0/UST/UST_Logs/multi-thread/david-desktop-20100811163524864824113/11520_5504068123890634635/ust_0),
 0, 0, , , 0, 0x0, MODE_UNKNOWN { firstthread = 5 }
ust.myevent: 18167.506735881
(/home/Large_Space/Part_B/LogStore/LTTngLog_wrlinux-4.0/UST/UST_Logs/multi-thread/david-desktop-20100811163524864824113/11520_5504068123890634635/ust_0),
 0, 0, , , 0, 0x0, MODE_UNKNOWN { firstthread = 7 }
ust.myevent: 18169.506818732
(/home/Large_Space/Part_B/LogStore/LTTngLog_wrlinux-4.0/UST/UST_Logs/multi-thread/david-desktop-20100811163524864824113/11520_5504068123890634635/ust_0),
 0, 0, , , 0, 0x0, MODE_UNKNOWN { firstthread = 8 }
ust.myevent: 18171.506903062
(/home/Large_Space/Part_B/LogStore/LTTngLog_wrlinux-4.0/UST/UST_Logs/multi-thread/david-desktop-20100811163524864824113/11520_5504068123890634635/ust_0),
 0, 0, , , 0, 0x0, MODE_UNKNOWN { firstthread = 10 }
End trace set

   we missed the trace logs:
   trace_mark(ust, myevent, "secondthread %d", number);

Oh, you created two events with same channel and same name, but with a
different first parameter name. This should be forbidden. UST should
take care of checking for these duplicate markers with non-matching
parameters.

libust marker.c is checking for this, as it should:

static int set_marker(struct marker_entry *entry, struct marker *elem,
                  int active)
{
          int ret = 0;
          WARN_ON(strcmp(entry->name, elem->name) != 0);

          if (entry->format) {
                  if (strcmp(entry->format, elem->format) != 0) {
                        DBG("Format mismatch for probe %s (%s), marker (%s)",
                                  entry->name,
                                  entry->format,
                                  elem->format);
                          return -EPERM;
                  }
          } else {

Pierre-Marc, why it this only showing the warning if UST_DEBUG is
defined ? This should always spit out the warning.

Agreed, it should probably be a WARN or ERR.

Nils/David, do you want to make a patch for this ?

pmf, I guess handing me a commit access might be handy.

Thanks!

Mathieu

pmf

--
David Goulet
LTTng project, DORSAL Lab.

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