I hope this DTrace branch gets merged with the default Erlang. I think is quite useful<br><br><div class="gmail_quote">On Thu, Sep 15, 2011 at 6:00 PM, Jason J. W. Williams <span dir="ltr"><<a href="mailto:jasonjwwilliams@gmail.com">jasonjwwilliams@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex;"><div bgcolor="#FFFFFF"><div>OpenIndiana and �(open Solaris) are great Rabbit platforms. FreeBSD has DTrace too. DTrace for Linux isn't up to snuff with the other platforms yet, but it's still worlds ahead of SystemTap.�</div>
<div><br></div><div>-J<br><br>Sent via iPhone<div><br></div><div>Is your email Premiere?</div></div><div><div></div><div class="h5"><div><br>On Sep 15, 2011, at 8:03, Alvaro Videla <<a href="mailto:videlalvaro@gmail.com" target="_blank">videlalvaro@gmail.com</a>> wrote:<br>
<br></div><div></div><blockquote type="cite"><div><a href="https://twitter.com/hylomorphism/status/114000680875851776" target="_blank"></a><a href="https://twitter.com/hylomorphism/status/114000680875851776" target="_blank"></a><a href="https://twitter.com/hylomorphism/status/114000680875851776" target="_blank"></a><a href="https://twitter.com/hylomorphism/status/114000680875851776" target="_blank"></a><a href="https://twitter.com/hylomorphism/status/114000680875851776" target="_blank"></a><div>
Hi,</div><div><br></div><div>I saw Matthew tweeting "Oh RabbitMQ, why are you taking over an hour to recover 100k queues? What /are/ you doing?!"�<a href="https://twitter.com/hylomorphism/status/114000680875851776" target="_blank"></a><a href="https://twitter.com/hylomorphism/status/114000680875851776" target="_blank">https://twitter.com/hylomorphism/status/114000680875851776</a>�</div>
<div><br></div><div>I've been doing some stuff at work with DTrace and I think is pretty cool when it comes to find out what a process is actually doing.</div><div><br></div><div>At the same time there's an experimental OTP fork on Github that adds Dtrace probes to Erlang:�<a href="https://github.com/dustin/otp/wiki/DTrace" target="_blank"></a><a href="https://github.com/dustin/otp/wiki/DTrace" target="_blank">https://github.com/dustin/otp/wiki/DTrace</a></div>
<div><br></div><div>See here for the available probes:�<a href="https://github.com/dustin/otp/blob/dtrace/erts/emulator/beam/erlang_dtrace.d" target="_blank"></a><a href="https://github.com/dustin/otp/blob/dtrace/erts/emulator/beam/erlang_dtrace.d" target="_blank">https://github.com/dustin/otp/blob/dtrace/erts/emulator/beam/erlang_dtrace.d</a></div>
<div><br></div><div>So for example running RabbitMQ based on that Erlang branch you could do things like in this gist:�<a href="https://gist.github.com/1219266" target="_blank"></a><a href="https://gist.github.com/1219266" target="_blank">https://gist.github.com/1219266</a></div>
<div><br></div><div>
<span style="font-family:helvetica, arial, freesans, clean, sans-serif;font-size:11px;line-height:14px"><pre style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;line-height:1.4em;font-family:'Bitstream Vera Sans Mono', Courier, monospace">
<div style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:1em;line-height:1.4em"><span style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;line-height:1.4em">erlang</span><span style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;line-height:1.4em">$</span><span style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;line-height:1.4em">target</span><span style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;line-height:1.4em">:::</span><span style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;line-height:1.4em;font-weight:bold">function</span><span style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;line-height:1.4em">-</span><span style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;line-height:1.4em">entry</span></div>
<div style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:1em;line-height:1.4em"><span style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;line-height:1.4em">/</span><span style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;line-height:1.4em">copyinstr</span><span style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;line-height:1.4em">(</span><span style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;line-height:1.4em">arg1</span><span style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;line-height:1.4em">)</span> <span style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;line-height:1.4em">==</span> <span style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;line-height:1.4em;color:rgb(221, 17, 68)">"rabbit_exchange_type_direct:route/2"</span><span style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;line-height:1.4em">/</span></div>
<div style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:1em;line-height:1.4em"><span style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;line-height:1.4em">{</span></div>
<div style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:1em;line-height:1.4em">����<span style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;line-height:1.4em">printf</span><span style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;line-height:1.4em">(</span><span style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;line-height:1.4em;color:rgb(221, 17, 68)">"%s %s"</span><span style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;line-height:1.4em">,</span> <span style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;line-height:1.4em">probemod</span><span style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;line-height:1.4em">,</span> <span style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;line-height:1.4em">probefunc</span><span style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;line-height:1.4em">);</span></div>
<div style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:1em;line-height:1.4em">����<span style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;line-height:1.4em">self</span><span style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;line-height:1.4em">-></span><span style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;line-height:1.4em">traceIt</span> <span style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;line-height:1.4em">=</span> <span style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;line-height:1.4em;color:rgb(0, 153, 153)">1</span><span style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;line-height:1.4em">;</span></div>
<div style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:1em;line-height:1.4em"><span style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;line-height:1.4em">}</span></div>
</pre></span></div><div><br></div><div>There I enable the flag traceIt only when route/2 is called on the direct exchange.</div><div><br></div><div>From there is just a matter of adding probes to different syscalls or io access etc based using patterns on that flag like:</div>
<div><span style="font-family:'Bitstream Vera Sans Mono', Courier, monospace;font-size:12px;line-height:16px;white-space:pre-wrap"><span style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;line-height:1.4em"><br>
</span></span></div><div><span style="font-family:'Bitstream Vera Sans Mono', Courier, monospace;font-size:12px;line-height:16px;white-space:pre-wrap"><span style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;line-height:1.4em">erlang</span><span style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;line-height:1.4em">$</span><span style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;line-height:1.4em">target</span><span style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;line-height:1.4em">:::</span><span style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;line-height:1.4em;font-weight:bold">function</span><span style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;line-height:1.4em">-</span><span style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;line-height:1.4em">entry</span></span></div>
<div><span style="font-family:'Bitstream Vera Sans Mono', Courier, monospace;font-size:12px;line-height:16px;white-space:pre-wrap"><span style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;line-height:1.4em">/</span><span style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;line-height:1.4em">self</span><span style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;line-height:1.4em">-></span><span style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;line-height:1.4em">traceIt</span><span style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;line-height:1.4em">/</span></span></div>
<div><span style="font-family:'Bitstream Vera Sans Mono', Courier, monospace;font-size:12px;line-height:16px;white-space:pre-wrap"><span style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;line-height:1.4em">{</span></span></div>
<div><span style="font-family:'Bitstream Vera Sans Mono', Courier, monospace;font-size:12px;line-height:16px;white-space:pre-wrap"><span style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;line-height:1.4em"> //do something here</span></span></div>
<div><span style="font-family:'Bitstream Vera Sans Mono', Courier, monospace;font-size:12px;line-height:16px;white-space:pre-wrap"><span style="margin-top:0px;margin-right:0px;margin-bottom:0px;margin-left:0px;padding-top:0px;padding-right:0px;padding-bottom:0px;padding-left:0px;line-height:1.4em">}</span></span></div>
<div><br></div><div>and so on.�</div><div><br></div><div>You can run the gist like:�<span style="color:rgb(51, 51, 51);font-family:helvetica, arial, freesans, clean, sans-serif;font-size:12px;line-height:18px">sudo dtrace -s route.d -p `pgrep beam.smp`</span></div>
<div><br></div><div>The examples are really basic but I think they illustrate the point. With that Erlang branch you could enable more granular probes than with the usual pid provider or dtruss.</div><div><br></div><div>
BTW, this works on Mac and Solaris. AFAIK on Linux some Kernel modules are required.</div>
<div><br></div><div>Cheers,</div><div><br></div><div>Alvaro</div>
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