https://bugs.lttng.org/https://bugs.lttng.org/themes/lttng/favicon/a.ico?14249722912013-08-14T21:52:12ZLTTng bugs repositoryLTTng-tools - Bug #607: lttng snapshot record fails for --buffers-pid traceshttps://bugs.lttng.org/issues/607?journal_id=17212013-08-14T21:52:12ZDavid Goulet
<ul><li><strong>Project</strong> changed from <i>LTTng</i> to <i>LTTng-tools</i></li></ul> LTTng-tools - Bug #607: lttng snapshot record fails for --buffers-pid traceshttps://bugs.lttng.org/issues/607?journal_id=17642013-08-22T20:47:39ZDavid Goulet
<ul><li><strong>Status</strong> changed from <i>New</i> to <i>Won't fix</i></li></ul><p>Can not reproduce with upstrea master.</p>
<p>I will close this one with invalid since it seems fixed on my side. If you can reproduce it, we'll reopen it and make sure to attach session daemon logs.</p>
<p>Thanks!</p> LTTng-tools - Bug #607: lttng snapshot record fails for --buffers-pid traceshttps://bugs.lttng.org/issues/607?journal_id=17692013-08-22T21:31:09ZDavid Goulet
<ul><li><strong>Status</strong> changed from <i>Won't fix</i> to <i>Invalid</i></li></ul> LTTng-tools - Bug #607: lttng snapshot record fails for --buffers-pid traceshttps://bugs.lttng.org/issues/607?journal_id=17912013-09-04T21:05:24ZDaniel U. Thibaultdaniel.thibault@drdc-rddc.gc.ca
<ul><li><strong>File</strong> <a href="/attachments/281">sessiond.log</a> <a class="icon-only icon-download" title="Download" href="/attachments/download/281/sessiond.log">sessiond.log</a> added</li></ul><p>Alas, I can still reproduce this using:</p>
<p>lttng-modules-2.3.0-rc2-7 c126f57<br />lttng-tools-2.3.0-rc3-1 3e618c7<br />lttng-ust-2.3.0-rc2-1 07d2f70<br />userspace-rcu-0.7.4-210-(0.7.7-69) e53ab1e</p>
<p>Ubuntu 12.04LTS 3.20-40-virtual, freshly rebooted</p>
<p>Same sequence of instructions as before:</p>
<pre>
$ lttng create snapsfind --snapshot
Session snapsfind created.
Default snapshot output set to: /home/daniel/lttng-traces/snapsfind-20130904-165608
Snapshot mode set. Every channel enabled for that session will be set in overwrite mode and mmap output.
$ lttng enable-channel ch0 --buffers-pid -u
UST channel ch0 enabled for session snapsfind
$ lttng enable-event -a -c ch0 -u
All UST events are enabled in channel ch0
$ lttng start
Tracing started for session snapsfind
$ /usr/src/lttng-ust-2.3.0-rc2/doc/examples/easy-ust/sample
sample starting
sample done
$ lttng snapshot record
Snapshot recorded successfully for session snapsfind
$ lttng destroy
Session snapsfind destroyed
</pre>
<p>The session and consumer daemon log was captured using:<br /><pre>
$ sudo lttng-sessiond -vvv -ZZZ 1 &> /home/daniel/lttng-traces/sessiond.log
</pre></p>
<p>(The '1' argument for '-ZZZ' is due to bug 588)</p> LTTng-tools - Bug #607: lttng snapshot record fails for --buffers-pid traceshttps://bugs.lttng.org/issues/607?journal_id=18802013-11-15T16:40:23ZDaniel U. Thibaultdaniel.thibault@drdc-rddc.gc.ca
<ul></ul><p>Finally figured this one out. It's a feature, not a bug. When tracing per-process ID, the buffers are evanescent, so you get a trace on disc <strong>only</strong> if you trigger the <code>record</code> action while the process is active. If the process has come and gone, so has its trace.</p>