----- Original Message ----- > From: "Karim Yaghmour" <[email protected]> > To: "Mathieu Desnoyers" <[email protected]> > Cc: [email protected] > Sent: Monday, February 17, 2014 10:09:37 AM > Subject: Re: [RFC PATCH lttng-modules] LTTng logger ABI > > > That was quick :) > > On 14-02-15 05:08 PM, Mathieu Desnoyers wrote: > > Add a user-space ABI (new file /proc/lttng-logger) to lttng-modules > > which can be written into by any user on the system. The content is > > saved into the kernel trace stream into the "lttng_logger" kernel event. > > Nice. I think this would do for the use-case we discussed (i.e. feedback > Android's "ATRACE" events into lttng instead of ftrace's "trace_marker" > file.)
Great! > > > The content of a single write is written into an lttng_logger event, > > provided the packet size is large enough to store the content. If it is > > not large enough, it won't be logged. However we cannot return any error > > to the caller, since there may be more than one trace session listening > > to this event. > > Can we just truncate instead of dropping if the event is too large? I'd be tempted to ask: is that the behavior of ftrace when receiving an event larger than a page through trace_marker ? We could indeed truncate the event, but it would increase complexity compared to the current patch. So I'm tempted to wait a bit before doing so. Thanks, Mathieu > > -- > Karim Yaghmour > CEO - Opersys inc. / www.opersys.com > http://twitter.com/karimyaghmour > > -- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com _______________________________________________ lttng-dev mailing list [email protected] http://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
