#dtrace — Public Fediverse posts
Live and recent posts from across the Fediverse tagged #dtrace, aggregated by home.social.
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Hunting Memory Leaks in bsnmpd with DTrace:
#dtrace #cybersecurity #informationsecurity #infosec #performance
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Hunting Memory Leaks in bsnmpd with DTrace:
#dtrace #cybersecurity #informationsecurity #infosec #performance
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Fable dishing out the compliments that those of us running these systems for decades have always known and advocated for.
"That DTrace trace was the whole game, by the way — owner identity from mdb plus lock/unlock pairing found one orphaned acquisition in 55k events and its exact stack. Nice platform to debug on."
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Fable dishing out the compliments that those of us running these systems for decades have always known and advocated for.
"That DTrace trace was the whole game, by the way — owner identity from mdb plus lock/unlock pairing found one orphaned acquisition in 55k events and its exact stack. Nice platform to debug on."
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Had a play with Claude Fable 5 to see if it could improve on my previous CTF performance work.
https://github.com/jperkin/illumos-gate/commits/ctf-performance/
Yeh, it gained another 33%, as well as finding some correctness issues. Now 42x faster than baseline, with 21x reduction in system time.
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Had a play with Claude Fable 5 to see if it could improve on my previous CTF performance work.
https://github.com/jperkin/illumos-gate/commits/ctf-performance/
Yeh, it gained another 33%, as well as finding some correctness issues. Now 42x faster than baseline, with 21x reduction in system time.
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Starting to get back into illumos/arm64. Current weekend project is getting DTrace working. Some initial progress:
# dtrace -n 'profile-997{@[stack()] = count();}' | tail
dtrace: description 'profile-997' matched 1 probe
genunix`taskq_thread+0x2e8
genunix`thread_exit
60xf9400e80
3910xd53b4221
genunix`thread_exit
3779Working fbt provider will be a bit harder...
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Starting to get back into illumos/arm64. Current weekend project is getting DTrace working. Some initial progress:
# dtrace -n 'profile-997{@[stack()] = count();}' | tail
dtrace: description 'profile-997' matched 1 probe
genunix`taskq_thread+0x2e8
genunix`thread_exit
60xf9400e80
3910xd53b4221
genunix`thread_exit
3779Working fbt provider will be a bit harder...
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After fixing up the pfsense gateway (forgot some log rotation, blew out the root dataset) I discovered that my home infra needs a little better observability.
I’d start with a timeseries db, and why not run under the new podman-on-freebsd-jails system? Should be quick and easy.
Anyway, I’ve discovered how to do things with jails that the manual says are explicitly forbidden, and I’m finally learning corners of dtrace I’ve never touched. Pray for me.
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After fixing up the pfsense gateway (forgot some log rotation, blew out the root dataset) I discovered that my home infra needs a little better observability.
I’d start with a timeseries db, and why not run under the new podman-on-freebsd-jails system? Should be quick and easy.
Anyway, I’ve discovered how to do things with jails that the manual says are explicitly forbidden, and I’m finally learning corners of dtrace I’ve never touched. Pray for me.
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If you are using #DTrace on #FreeBSD, then I've got good news for you.
I've added a new manual to FreeBSD. It's called d(7) and it is a short reference of the #D scripting language. Currently, it covers only a subset of all variables and functions, but we'll add more iteratively.
Here are some previews for you:
HTML: https://people.freebsd.org/~0mp/d.7.html
MDOC (view with man(1)): https://people.freebsd.org/~0mp/d.7
Have fun tracing your systems!
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If you are using #DTrace on #FreeBSD, then I've got good news for you.
I've added a new manual to FreeBSD. It's called d(7) and it is a short reference of the #D scripting language. Currently, it covers only a subset of all variables and functions, but we'll add more iteratively.
Here are some previews for you:
HTML: https://people.freebsd.org/~0mp/d.7.html
MDOC (view with man(1)): https://people.freebsd.org/~0mp/d.7
Have fun tracing your systems!
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@monospace Sounds pretty cool. It might be interesting to add a similar functionality as a #dwatch profile to #FreeBSD.
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@monospace Sounds pretty cool. It might be interesting to add a similar functionality as a #dwatch profile to #FreeBSD.
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everytime someone mentions #dtrace on the internet @briancantrell drinks a diet coke
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everytime someone mentions #dtrace on the internet @briancantrell drinks a diet coke
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I've just committed a new manual page to #FreeBSD: tracing(7), an introduction to #tracing and #performance #monitoring facilities.
It'll take a moment before it is available for readers on man.freebsd.org, so for the time being you can grab a copy from here (https://cgit.freebsd.org/src/plain/share/man/man7/tracing.7?id=c29459f901dc73e1ebe1e654da2677cc0b7bd296) and open it with man(1).
#DTrace #dwatch #ktrace #osdev #foss #ptrace #utrace #truss #boottrace #tslog
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I've just committed a new manual page to #FreeBSD: tracing(7), an introduction to #tracing and #performance #monitoring facilities.
It'll take a moment before it is available for readers on man.freebsd.org, so for the time being you can grab a copy from here (https://cgit.freebsd.org/src/plain/share/man/man7/tracing.7?id=c29459f901dc73e1ebe1e654da2677cc0b7bd296) and open it with man(1).
#DTrace #dwatch #ktrace #osdev #foss #ptrace #utrace #truss #boottrace #tslog
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@mhoye
#SystemTap or #DTrace might offer what you are looking for
https://sourceware.org/systemtap/wiki
https://www.brendangregg.com/dtrace.html -
Enabling DTrace in Python on FreeBSD (again)
https://antranigv.am/posts/2025/02/dtrace-python-freebsd-again/
Last night I was running our usual Greybeard AMA on FreeBSD’s Discord server, 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
--with-dtraceoption.As a sane person, I setup a Jail (using Jailer, of course), cloned the FreeBSD ports tree and added the
--with-dtraceoption back. It did not compile.The first issue that we encountered was the following:
--- Include/pydtrace_probes.h ---dtrace: option requires an argument -- s
ah yes, looking over the Makefile we see the following
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_/' $@ > [email protected] mv [email protected] $@
(you can also view the source here)
As far as I can tell, the
$<thingie does not work with BSD Make, so how about if we try usinggmakeinstead?I did the following changes to the
Makefilein the FreeBSD Ports tree. Basically addinggmakeintoUSES=.USES= compiler:c11 cpe ncurses pathfix pkgconfig \- python:${PYTHON_DISTVERSION:R},env readline shebangfix ssl tar:xz+ python:${PYTHON_DISTVERSION:R},env readline shebangfix ssl tar:xz gmakeNow let’s try compiling again.
We get the following errors now:
ld: error: undefined symbol: __dtraceenabled_python___function__entry
Ah yes, linking issues.
After an hour of digging we learned that the
DTRACE_OBJS=variable is set to… nothing. But it needs to be set toPython/pydtrace.o. I was not able to fix this issue properly (inconfigure,configure.ac, or whatever madness that GNU Autotools use), so I just changed the line manually in theMakefile.Now let’s try compiling again.
We get the following error:
./Python/sysmodule.c:223:24: warning: passing 'const char *' to parameter of type 'char *' discards qualifiers [-Wincompatible-pointer-types-discards-qualifiers]
Someone in the Discord chat recommended that I disable the LTO (Link-Time Optimization) option.
I did
make clean, 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
make install===> 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...
good! now let’s try DTrace with Python!
In one terminal, I ran Python, and in another one I got the following
# 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
Woohoo! Now I’m happy!
Okay, so what did we learn?
- There’s a little bit of GNUMake-ism in Python’s Makefile. Either we have to use
gmakein FreeBSD when building Python or we need to submit an alternative to the upstream - Die GNU Autotools… I mean… the GNU Autotools usage in Python has an issue, where the generated Makefile does not set the
DTRACE_OBJScorrectly. Can anyone help with this? As a Pascal guy, reading GNU configure files makes me wanna die. - LTO is problematic. Solutions?
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.
- There’s a little bit of GNUMake-ism in Python’s Makefile. Either we have to use
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Hard to believe it’s been 20 years since the first publication of #OpenSolaris source code with the #DTrace source release:
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It arrived! Huge thanks to @danmcd for arranging shipping to the UK.
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Star Wars reference at dtrace.conf? It's like my two favorite things merging into the same universe.
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Who would have thought that we would have #DTrace on #Windows... https://learn.microsoft.com/en-us/windows-hardware/drivers/devtest/dtrace
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DTrace 2.0, the powerful dynamic tracing tool, is now available on Gentoo #Dtrace #Gentoo #Linux
https://ostechnix.com/dtrace-2-0-arrives-on-gentoo-linux/
