On Wed, 26 Sep 2007 11:22:35 -0700 David J. Wilder wrote:

> diff --git a/Documentation/trace.txt b/Documentation/trace.txt
> new file mode 100644
> index 0000000..0e42fb8
> --- /dev/null
> +++ b/Documentation/trace.txt
> @@ -0,0 +1,160 @@
> +Trace User Interface
> +===================
> +When a trace channel is created and started, the following
> +directories and files are created in the root of the mounted debugfs.
> +
> +/debug (root of the debugfs)
> +     /<trace-root-dir>
> +             /<trace-name>
> +                     trace0...traceN-1  Per-CPU trace data, one
> +                                        file per CPU.
> +
> +                     state              Start or stop tracing by
> +                                        by writing the strings
> +                                        "start" or "stop" to this
> +                                        file. Read the file to get the
> +                                        current state.
> +
> +                     dropped            The number of records dropped
> +                                        due to a full-buffer condition,
> +                                        for non-TRACE_FLIGHT_CHANNELs
> +                                        only.
> +
> +                     rewind             Trigger a rewind by writing
> +                                        to this file.  i.e. start
> +                                        next read at the beginning
> +                                        again. Only available for
> +                                        TRACE_FLIGHT_CHANNELS.
> +
> +
> +                     nr_sub             Number of sub-buffers
> +                                        in the channel.
> +
> +                     sub_size           Size of sub-buffers in
> +                                        the channnel.
> +
> +Trace data is gathered from the trace[0...N] files using one of the
> +available interfaces provided by relay.

For your next patchset (whenever that is), above should be
                                   trace[0...N-1] files

> +When using the read(2) interface, as data is read it is marked as
> +consumed by the relay subsystem.  Therefore, subsequent reads will
> +only return unconsumed data.


---
~Randy
Phaedrus says that Quality is about caring.
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