DTrace
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DTrace on Gentoo
Overlay repository
The ebuilds for DTrace are placed (in time of writing) in GitHub repository.
https://github.com/robertek/dtrace-portage-overlay
To activate the repository just add new repository configuration to your Portage config.
FILE
/etc/portage/repos.conf/dtrace[dtrace]
location = /var/lib/portage/dtrace
sync-type = git
sync-uri = https://github.com/robertek/dtrace-portage-overlay
auto-sync = yes
Then sync Portage tree.
Installation
DTrace support on Gentoo consists of kernel sources with patches and userspace utilities. It is packed in 3 packages:
- libctf => library for CTF debug info handling, needed for both the kernel and user utilities
- dtrace-user => userspace part, mainly the dtrace(1) command and libdtrace
- dtrace-sources => kernel 4.14.x sources containing dtrace patches and working initial .config
The default installation can be done installing just the dtrace-user:
root #emerge --ask dtrace-user Note
The dtrace-sources is needed for dtrace-user because of header dependencies. If you plan to manage your local sources in Git or different way you need link /usr/include/linux/dtrace -> /your/src/path/dtrace-linux-src/include/uapi/linux/dtrace
The dtrace-sources is needed for dtrace-user because of header dependencies. If you plan to manage your local sources in Git or different way you need link /usr/include/linux/dtrace -> /your/src/path/dtrace-linux-src/include/uapi/linux/dtrace
Kernel
Build the kernel your way. The main difference to normal building is executing make ctf before kernel installation. This will generate CTF debug data for DTrace to work.
Example steps:
root #cd /usr/src/linux-4.14.28-dtrace
root #make oldconfig
root #make
root #make ctf
root #make install
root #make modules_install
Important
Do not expect to be able to create kernel with custom config, it may end with dwarf2ctf tool crashing (when I developed these ebuilds I tried my own config for 4.14 without luck). Suggested is using the config provided from dtrace-sources (which is based on Oracle UEK kernel config) and than striping it down or up your way.
Do not expect to be able to create kernel with custom config, it may end with dwarf2ctf tool crashing (when I developed these ebuilds I tried my own config for 4.14 without luck). Suggested is using the config provided from dtrace-sources (which is based on Oracle UEK kernel config) and than striping it down or up your way.
Test it
When everything passed correctly you may try some basic DTrace one-liner.
root #
dtrace -n 'proc:::exec-success { trace(curpsinfo->pr_psargs); }'dtrace: description 'proc:::exec-success ' matched 1 probe CPU ID FUNCTION:NAME 3 2017 do_execveat_common:exec-success /usr/bin/konsole 3 2017 do_execveat_common:exec-success git --version 3 2017 do_execveat_common:exec-success grep --color=auto 3 2017 do_execveat_common:exec-success grep --exclude-dir=.cvs 3 2017 do_execveat_common:exec-success dircolors -b 3 2017 do_execveat_common:exec-success ls --color -d .Ctrl+c
References
To start learning DTrace check some informative guides: