[ltt-dev] UST communication library

Yannick Brosseau yannick.brosseau at gmail.com
Wed Jun 15 11:01:34 EDT 2011

On 2011-06-15 10:57, David Goulet wrote:
> On 11-06-15 01:23 AM, Alexandre Montplaisir wrote:
>> Hi David,
>> Sorry if I missed it, but what is the ultimate goal with lttng-tools? Is it to
>> A) Become the unified trace controller for LTTng (kernel) and UST (userspace)
>> tracers.
>> or
>> B) Become a generic trace controller which people could "plug" their tracers
>> into, and which would come with initial support for LTTng and UST.
>> If it's A) and only A), I'd say yank the separate "libust" and merge it into
>> lttng-tools' tree. This is what happened with "lttctl", which is now statically
>> built in lttng-tools, right?
>> However modularity is never bad, perhaps going with an architecture like B) is
>> better long-term.
>> Some suggestions:
>>> So the problem is where this lib should go? Here are the possibilities I've
>>> discussed with Mathieu:
>>> 1) Keep libustcomm in UST and linking it in lttng-tools. Cons : direct
>>> dependency! ... not good
>> 1b) Have an *optional* dependency on UST. At configure time, lttng-tools could
>> check if libust is present, if so compile it with UST support. If not, only
>> compile with kernel support. ("Warning, libust not found, UST support will not
>> be available", something like that)
> This is problematic for packaging...
No, this is not problematic. When we create a package, we just have to
build-depend on UST. That way, people who wants to build it by hand
without UST, don't need to install UST.
Also, for distro like gentoo, you can build your package with UST support.


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