toolchain/share/doc/gdb/Trace-Files.html

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Previous:&nbsp;<a rel="previous" accesskey="p" href="Tracepoint-Variables.html#Tracepoint-Variables">Tracepoint Variables</a>,
Up:&nbsp;<a rel="up" accesskey="u" href="Tracepoints.html#Tracepoints">Tracepoints</a>
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<h3 class="section">13.4 Using Trace Files</h3>
<p><a name="index-trace-files-943"></a>
In some situations, the target running a trace experiment may no
longer be available; perhaps it crashed, or the hardware was needed
for a different activity. To handle these cases, you can arrange to
dump the trace data into a file, and later use that file as a source
of trace data, via the <code>target tfile</code> command.
<a name="index-tsave-944"></a>
<dl><dt><code>tsave [ -r ] </code><var>filename</var><dt><code>tsave [-ctf] </code><var>dirname</var><dd>Save the trace data to <var>filename</var>. By default, this command
assumes that <var>filename</var> refers to the host filesystem, so if
necessary <span class="sc">gdb</span> will copy raw trace data up from the target and
then save it. If the target supports it, you can also supply the
optional argument <code>-r</code> (&ldquo;remote&rdquo;) to direct the target to save
the data directly into <var>filename</var> in its own filesystem, which may be
more efficient if the trace buffer is very large. (Note, however, that
<code>target tfile</code> can only read from files accessible to the host.)
By default, this command will save trace frame in tfile format.
You can supply the optional argument <code>-ctf</code> to save data in CTF
format. The <dfn>Common Trace Format</dfn> (CTF) is proposed as a trace format
that can be shared by multiple debugging and tracing tools. Please go to
&lt;<code>http://www.efficios.com/ctf</code>&gt; to get more information.
<p><a name="index-target-tfile-945"></a><a name="index-tfile-946"></a><a name="index-target-ctf-947"></a><a name="index-ctf-948"></a><br><dt><code>target tfile </code><var>filename</var><dt><code>target ctf </code><var>dirname</var><dd>Use the file named <var>filename</var> or directory named <var>dirname</var> as
a source of trace data. Commands that examine data work as they do with
a live target, but it is not possible to run any new trace experiments.
<code>tstatus</code> will report the state of the trace run at the moment
the data was saved, as well as the current trace frame you are examining.
Both <var>filename</var> and <var>dirname</var> must be on a filesystem accessible to
the host.
<pre class="smallexample"> (gdb) target ctf ctf.ctf
(gdb) tfind
Found trace frame 0, tracepoint 2
39 ++a; /* set tracepoint 1 here */
(gdb) tdump
Data collected at tracepoint 2, trace frame 0:
i = 0
a = 0
b = 1 '\001'
c = {"123", "456", "789", "123", "456", "789"}
d = {{{a = 1, b = 2}, {a = 3, b = 4}}, {{a = 5, b = 6}, {a = 7, b = 8}}}
(gdb) p b
$1 = 1
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