Messages in this thread | | | Date | Tue, 8 Mar 2011 19:07:54 -0500 | From | Mathieu Desnoyers <> | Subject | Re: [PATCH][RFC] tracing: Enable tracepoints via module parameters |
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* Steven Rostedt (rostedt@goodmis.org) wrote: > On Tue, 2011-03-08 at 18:22 -0500, Mathieu Desnoyers wrote: > > * Steven Rostedt (rostedt@goodmis.org) wrote: > > > A few months ago it was suggested to have a way to enable tracepoints in > > > a module when it is loaded. I tried various methods, but this one seems > > > to be the least intrusive. In fact, it requires no modification to the > > > module code. > > > > > > The trace event now adds its own MODULE_INFO() and kernel_param_ops that > > > and links the information about a tracepoint into the module's __param > > > section. A module can be loaded with a tracepoint active by adding > > > trace_<tracepoint>=1 as one of the parameters. > > > > Hi Steven, > > > > Can you walk me through the expected sequence someone wanting to enable a few > > specific module tracepoints would have to go through ? I'm thinking here about > > the context of a distro which has on-demand module loading. The scenario I am > > thinking about is a distro specifying a basic set of tracepoints to enable in a > > "standard catch-all tracing configuration", which includes some tracepoints in > > yet-unloaded modules. I'm trying to figure out what the end user experience will > > look like if we go for the solution you propose here. > > > > You would add it like any other module parameter. > > Just update it in your /etc/modprobe.d/ directory.
So what you are saying here is that modifying /etc/modprobe.d/ is the actual interface you propose presenting to the end-users to control their tracepoints ?
Maybe I am missing something, but this interface seems to lack the layer of finish we might want to put into a user-visible API. I don't really see how distributions can hope to automate any of this for their end-user without making a mess of the /etc/modprobe.d/ they ship with.
Thanks,
Mathieu
-- Mathieu Desnoyers Operating System Efficiency R&D Consultant EfficiOS Inc. http://www.efficios.com
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