From mboxrd@z Thu Jan  1 00:00:00 1970
From: karim.yaghmour@opersys.com (Karim Yaghmour)
Date: Mon, 17 Feb 2014 10:09:37 -0500
Subject: [lttng-dev] [RFC PATCH lttng-modules] LTTng logger ABI
In-Reply-To: <1392502096-1900-1-git-send-email-mathieu.desnoyers@efficios.com>
References: <1392502096-1900-1-git-send-email-mathieu.desnoyers@efficios.com>
Message-ID: <53022631.90209@opersys.com>


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.)

> 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?

-- 
Karim Yaghmour
CEO - Opersys inc. / www.opersys.com
http://twitter.com/karimyaghmour