5 ms·

I'd like to learn DTrace (especially after the recent 20yr podcast episode), but I worry it'll never make into mainstream Linux debugging, and hence only useful

by bbkane 3y ago

I'd like to learn DTrace (especially after the recent 20yr podcast episode), but I worry it'll never make into mainstream Linux debugging, and hence only useful for more niche jobs.

sunshowers 3y ago
Your concern is completely reasonable -- a thing I'd add though is that both Windows and macOS have DTrace support.
- 4ad 3y ago
  DTrace in macOS was always a third class citizen, it never worked very well, and in fact, on arm64 machines it doesn't work at all (panics the kernel).
  - sunshowers 3y ago
    That's really unfortunate :(
- bbkane 3y ago
  I was excited, but it looks like both MacOS and Windows require special admin permissions for my laptop that I doubt my work would approve (completely reasonable to require this, it just makes it unusable for me).
  - 4ad 3y ago
    It's actually not reasonable to require this if you do it right. On Solaris and illumos DTrace works just fine for a normal user. You simply have access to fewer probes if you are less privileged. Not the case on FreeBSD/Windows/macOS, where it's all or nothing. Still, on FreeBSD you just need root, on macOS you need to boot into a special kernel mode which doesn't even work on modern Apple Silicon machines.
roland-s 3y ago
Linux now has eBPF, which is essentially a VM running inside the Linux kernel. You can run your own programs on this little VM and extend the kernel to a staggering degree. Some clever folks have used this to build open source tracing tools that rival and even surpass Dtrace in some ways. Brendan Gregg, a Dtrace wizard and old colleague of some of the Oxide team back at Sun and Joyent, has some great resources on the subject https://www.brendangregg.com/ebpf.html https://www.brendangregg.com/ebpf.html https://www.brendangregg.com/blog/2018-10-08/dtrace-for-linux-2018.html https://www.brendangregg.com/blog/2018-10-08/dtrace-for-linu...

by bbkane 3y ago

I'd like to learn DTrace (especially after the recent 20yr podcast episode), but I worry it'll never make into mainstream Linux debugging, and hence only useful for more niche jobs.

sunshowers 3y ago

Your concern is completely reasonable -- a thing I'd add though is that both Windows and macOS have DTrace support.

4ad 3y ago
DTrace in macOS was always a third class citizen, it never worked very well, and in fact, on arm64 machines it doesn't work at all (panics the kernel).
- sunshowers 3y ago
  That's really unfortunate :(
bbkane 3y ago
I was excited, but it looks like both MacOS and Windows require special admin permissions for my laptop that I doubt my work would approve (completely reasonable to require this, it just makes it unusable for me).
- 4ad 3y ago
  It's actually not reasonable to require this if you do it right. On Solaris and illumos DTrace works just fine for a normal user. You simply have access to fewer probes if you are less privileged. Not the case on FreeBSD/Windows/macOS, where it's all or nothing. Still, on FreeBSD you just need root, on macOS you need to boot into a special kernel mode which doesn't even work on modern Apple Silicon machines.

roland-s 3y ago

Linux now has eBPF, which is essentially a VM running inside the Linux kernel. You can run your own programs on this little VM and extend the kernel to a staggering degree. Some clever folks have used this to build open source tracing tools that rival and even surpass Dtrace in some ways. Brendan Gregg, a Dtrace wizard and old colleague of some of the Oxide team back at Sun and Joyent, has some great resources on the subject https://www.brendangregg.com/ebpf.html https://www.brendangregg.com/ebpf.html https://www.brendangregg.com/blog/2018-10-08/dtrace-for-linux-2018.html https://www.brendangregg.com/blog/2018-10-08/dtrace-for-linu...