On Thu, Apr 10, 2014 at 03:45:51PM -0400, David Goulet wrote: > On 03 Apr (12:57:43), Jan Glauber wrote: > > Hi LTTng'ers, > > > > I've asked briefly for the configurable probes feature at the Tracing > > summit, > > here is an RFC how we could implement it. > > > > Why I want to have this feature: > > Currently the LTTng probes that are loaded when a session is created are > > defined > > in a static list. If the user wants to change the loaded probes (for > > instance > > disable the very noisy rcu) then lttng-tools must be recompiled or the > > modules must > > be blacklisted or deleted. I also found that in our embedded environment > > the default > > busybox configuration is to disable the blacklist feature, so blacklisting > > is not an > > option. > > > > Therefore I want to have a more flexible way of defining which probes to > > load > > on session start. We could use an environment variable that (if present) > > overrides the default and only loads the probes named in the variable. > > > > Patch 1 is a cleanup and patch 2 & 3 are preparation for the feature in > > patch 4. > > Please review and give feedback if this approach is feasible. > > Hi Jan, > > First of all, thanks for this! Except some syntax issue, this looks > great! Sorry took a while to respond, busy busy improving lttng :P.
Hi David, thanks for reviewing! Also, I hope part of the improvement work was to decide on the name for the 2.5 release ;- > Before we go further in mergin this, I see you took the approach of > adding an env. variable to provide the list of probes you want to load. > Right now in the upstream master (for 2.5), we have the support for a > configuration file for lttng-sessiond. Could it be a way you would > prefer (or use) instead of env. var? I understand that embedded stuff, a > conf file might not be preferable. Actually a config file was my first thought also, but I only found the .lttngrc which is generated when a session is started. Where is the sessiond config file located? I don't see a config file under /etc or in the home directory. > Anyhow, I'm comfortable merging this and adding this env. var but an > option in the configuration file could also be awesome! :) > > One thing that would be great if you have a minute, is to send me a > patch for the man page update of that new variable. I'll do that when we've decided about config file vs. env variable... --Jan > Cheers! > David > > > > > thanks, > > Jan > > --- > > Harman Becker Automotive GmbH > > System Profiling & Optimizing Team > > > > > > Jan Glauber (4): > > Use common functions for module loading and unloading > > Seperate probe modules from control modules > > Remove required parameter from module parameters > > Dynamic probe list support > > > > src/bin/lttng-sessiond/kern-modules.h | 3 +- > > src/bin/lttng-sessiond/modprobe.c | 292 > > ++++++++++++++++++--------------- > > src/common/defaults.h | 3 + > > src/common/utils.c | 10 ++ > > src/common/utils.h | 1 + > > 5 files changed, 172 insertions(+), 137 deletions(-) > > > > -- > > 1.7.9.5 > > > > > > _______________________________________________ > > lttng-dev mailing list > > [email protected] > > http://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev _______________________________________________ lttng-dev mailing list [email protected] http://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
