#DTrace

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Claudius Link<a href="https://mastodon.social/@mhoye" class="u-url mention" rel="nofollow noopener noreferrer" target="_blank">@mhoye</a> <a href="https://infosec.exchange/tags/SystemTap" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#SystemTap</a> or <a href="https://infosec.exchange/tags/DTrace" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#DTrace</a> might offer what you are looking for <a href="https://sourceware.org/systemtap/wiki" rel="nofollow noopener noreferrer" translate="no" target="_blank">https://sourceware.org/systemtap/wiki</a> <a href="https://www.brendangregg.com/dtrace.html" rel="nofollow noopener noreferrer" translate="no" target="_blank">https://www.brendangregg.com/dtrace.html</a>

Antranig VartanianEnabling DTrace in Python on FreeBSD (again)<a href="https://antranigv.am/posts/2025/02/dtrace-python-freebsd-again/" rel="nofollow noopener noreferrer" translate="no" target="_blank">https://antranigv.am/posts/2025/02/dtrace-python-freebsd-again/</a>Last night I was running our usual Greybeard AMA on <a href="https://wiki.freebsd.org/Discord/DiscordServer" rel="nofollow noopener noreferrer" target="_blank">FreeBSD’s Discord server</a>, when someone asked “I’ve been using Linux for years, but I also like FreeBSD. what can I do for FreeBSD, and what can FreeBSD do for me, as a Python Full Stack Developer?”I started talking about FreeBSD Jails, ZFS, Boot Environments and more, but I also wanted to focus on DTrace. The ability to dynamically trace on production still sounds like magic to me. I know it isn’t, I’ve read the code and the papers, but the fact that I can ask the operating system questions on the fly, without recompiling, is amazing.So when I was demoing DTrace, I also wanted to show the DTrace integrations with Python. Little did I know that the Python package on FreeBSD was not compiled with the <code>--with-dtrace</code> option.As a sane person, I setup a Jail (using <a href="https://jailer.dev/" rel="nofollow noopener noreferrer" target="_blank">Jailer</a>, of course), cloned the FreeBSD ports tree and added the <code>--with-dtrace</code> option back. It did not compile.The first issue that we encountered was the following:<pre>--- Include/pydtrace_probes.h ---dtrace: option requires an argument -- s</pre>ah yes, looking over the Makefile we see the following<pre>Include/pydtrace_probes.h: $(srcdir)/Include/pydtrace.d $(MKDIR_P) Include $(DTRACE) $(DFLAGS) -o $@ -h -s $< : sed in-place edit with POSIX-only tools sed 's/PYTHON_/PyDTrace_/' $@ > $@.tmp mv $@.tmp $@</pre>(you can also view the source <a href="https://github.com/python/cpython/blob/v3.11.11/Makefile.pre.in#L1454C1-L1459C99" rel="nofollow noopener noreferrer" target="_blank">here</a>)As far as I can tell, the <code>$<</code> thingie does not work with BSD Make, so how about if we try using <code>gmake</code> instead?I did the following changes to the <code>Makefile</code> in the FreeBSD Ports tree. Basically adding <code>gmake</code> into <code>USES=</code>.<pre> USES= compiler:c11 cpe ncurses pathfix pkgconfig \- python:${PYTHON_DISTVERSION:R},env readline shebangfix ssl tar:xz+ python:${PYTHON_DISTVERSION:R},env readline shebangfix ssl tar:xz gmake</pre>Now let’s try compiling again.We get the following errors now:<pre>ld: error: undefined symbol: __dtraceenabled_python___function__entry</pre>Ah yes, linking issues.After an hour of digging we learned that the <code>DTRACE_OBJS=</code> variable is set to… nothing. But it needs to be set to <code>Python/pydtrace.o</code>. I was not able to fix this issue properly (in <code>configure</code>, <code>configure.ac</code>, or whatever madness that GNU Autotools use), so I just changed the line manually in the <code>Makefile</code>.Now let’s try compiling again.We get the following error:<pre>./Python/sysmodule.c:223:24: warning: passing 'const char *' to parameter of type 'char *' discards qualifiers [-Wincompatible-pointer-types-discards-qualifiers]</pre>Someone in the Discord chat recommended that I disable the LTO (Link-Time Optimization) option.I did <code>make clean</code>, I patched that line again, and here we go, one more time.It’s compiling, it’s compiling, it’s compiling… aaaaand we’re done! Let’s do <code>make install</code><pre>===> Installing for python311-3.11.11===> Checking if python311 is already installed===> Registering installation for python311-3.11.11[python.srv0.hackerspace.am] Installing python311-3.11.11...</pre>good! now let’s try DTrace with Python!In one terminal, I ran Python, and in another one I got the following<pre># dtrace -l -n 'python*:::' ID PROVIDER MODULE FUNCTION NAME85302 python8737 libpython3.11.so.1.0 sys_audit audit85303 python8737 libpython3.11.so.1.0 sys_audit_tstate audit85304 python8737 libpython3.11.so.1.0 _PyEval_EvalFrameDefault function-entry85305 python8737 libpython3.11.so.1.0 dtrace_function_return function-return85306 python8737 libpython3.11.so.1.0 _PyEval_EvalFrameDefault function-return85307 python8737 libpython3.11.so.1.0 gc_collect_main gc-done85308 python8737 libpython3.11.so.1.0 gc_collect_main gc-start85309 python8737 libpython3.11.so.1.0 PyImport_ImportModuleLevelObject import-find-load-done85310 python8737 libpython3.11.so.1.0 PyImport_ImportModuleLevelObject import-find-load-start85311 python8737 libpython3.11.so.1.0 _PyEval_EvalFrameDefault line</pre>Woohoo! Now I’m happy!Okay, so what did we learn?<ul><li>There’s a little bit of GNUMake-ism in Python’s Makefile. Either we have to use <code>gmake</code> in FreeBSD when building Python or we need to submit an alternative to the upstream</li><li>Die GNU Autotools… I mean… the GNU Autotools usage in Python has an issue, where the generated Makefile does not set the <code>DTRACE_OBJS</code> correctly. Can anyone help with this? As a Pascal guy, reading GNU configure files makes me wanna die.</li><li>LTO is problematic. Solutions?</li></ul>The real question is, how can we enable DTrace by default in FreeBSD packages for Python. DTrace is one of our market advantages and we should find a way to enable it everywhere we can.This was a fun Greybeard AMA, where we touched multiple parts of the system. Looking forward for next week!That’s all folks…Reply via email.<a rel="nofollow noopener noreferrer" class="hashtag u-tag u-category" href="https://antranigv.am/tags/debugging/" target="_blank">#debugging</a> <a rel="nofollow noopener noreferrer" class="hashtag u-tag u-category" href="https://antranigv.am/tags/dtrace/" target="_blank">#DTrace</a> <a rel="nofollow noopener noreferrer" class="hashtag u-tag u-category" href="https://antranigv.am/tags/freebsd/" target="_blank">#FreeBSD</a> <a rel="nofollow noopener noreferrer" class="hashtag u-tag u-category" href="https://antranigv.am/tags/gnu/" target="_blank">#GNU</a> <a rel="nofollow noopener noreferrer" class="hashtag u-tag u-category" href="https://antranigv.am/tags/python/" target="_blank">#Python</a>

Solaris DiasporaHard to believe it’s been 20 years since the first publication of <a href="https://techhub.social/tags/OpenSolaris" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#OpenSolaris</a> source code with the <a href="https://techhub.social/tags/DTrace" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#DTrace</a> source release: <a href="https://web.archive.org/web/20050208015516/http://www.sun.com/smi/Press/sunflash/2005-01/sunflash.20050125.1.html" rel="nofollow noopener noreferrer" translate="no" target="_blank">https://web.archive.org/web/20050208015516/http://www.sun.com/smi/Press/sunflash/2005-01/sunflash.20050125.1.html</a>

Jonathan PerkinIt arrived! Huge thanks to <a href="https://hostux.social/@danmcd" class="u-url mention" rel="nofollow noopener noreferrer" target="_blank">@danmcd</a> for arranging shipping to the UK.<a href="https://federate.me.uk/tags/dtrace" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#dtrace</a> <a href="https://federate.me.uk/tags/dtraceconf24" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#dtraceconf24</a>

Antranig Vartanian :freebsd:Star Wars reference at dtrace.conf? It's like my two favorite things merging into the same universe.<a href="https://sigin.fo/tags/DTrace" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#DTrace</a> <a href="https://sigin.fo/tags/StarWars" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#StarWars</a>

Mike Zeller :aim_logo:Messing around with the new 3D printer and decided to do some coasters before dtrace.conf tomorrow! <a href="https://hachyderm.io/tags/illumos" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#illumos</a> <a href="https://hachyderm.io/tags/dtrace" class="mention hashtag" rel="nofollow noopener noreferrer" target="_blank">#dtrace</a>

linuxDTrace 2.0 Arrives On Gentoo Linux DTrace 2.0, the powerful dynamic tracing tool, is now availabl... <a href="https://www.linuxconsultant.org/dtrace-2-0-arrives-on-gentoo-linux/" rel="nofollow noopener noreferrer" target="_blank">https://www.linuxconsultant.org/dtrace-2-0-arrives-on-gentoo-linux/</a> <a rel="nofollow noopener noreferrer" class="mention hashtag" href="https://mastodon.social/tags/blog" target="_blank">#blog</a> <a rel="nofollow noopener noreferrer" class="mention hashtag" href="https://mastodon.social/tags/DTrace" target="_blank">#DTrace</a> <a href="https://awakari.com/pub-msg.html?id=2o5uQBHoYGTdu6Qw28R1VRFE5Cr" rel="nofollow noopener noreferrer" target="_blank">Event Attributes</a>

linuxDTrace 2.0 Arrives On Gentoo Linux DTrace 2.0, the powerful dynamic tracing tool, is now availabl... <a href="https://www.linuxtoday.com/blog/dtrace-2-0-arrives-on-gentoo-linux/" rel="nofollow noopener noreferrer" target="_blank">https://www.linuxtoday.com/blog/dtrace-2-0-arrives-on-gentoo-linux/</a> <a rel="nofollow noopener noreferrer" class="mention hashtag" href="https://mastodon.social/tags/Blog" target="_blank">#Blog</a> <a rel="nofollow noopener noreferrer" class="mention hashtag" href="https://mastodon.social/tags/DTrace" target="_blank">#DTrace</a> <a href="https://awakari.com/pub-msg.html?id=2o5nQrE8Bbhysdj3cNp7X0UQqNS" rel="nofollow noopener noreferrer" target="_blank">Event Attributes</a>

🦀 RustLab Conference🎤 We’re excited to have Adam Leventhal, one of the original authors of DTrace, at <a href="https://mastodon.uno/tags/RustLab2024" class="mention hashtag" rel="tag">#RustLab2024</a>! 🌟 Join the talk "DTrace for Rust... and Everything Else Too!" 👉 <a href="https://rustlab.it/speakers/adam-leventhal" target="_blank" rel="nofollow noopener noreferrer" translate="no">https://rustlab.it/speakers/adam-leventhal</a> <a href="https://mastodon.uno/tags/RustLang" class="mention hashtag" rel="tag">#RustLang</a> <a href="https://mastodon.uno/tags/DTrace" class="mention hashtag" rel="tag">#DTrace</a> <a href="https://mastodon.social/@ahl" class="u-url mention">@ahl</a>

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