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Commit fb91ee6c authored by Pekka Paalanen's avatar Pekka Paalanen Committed by Ingo Molnar
Browse files

tracing, doc: update mmiotrace documentation 



Impact: update documentation

Update to reflect the current state of the tracing framework:

 - "none" tracer has been replaced by "nop" tracer
 - tracing_enabled must be toggled when changing buffer size

Signed-off-by: default avatarPekka Paalanen <pq@iki.fi>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 7ee1768d

Documentation/tracers/mmiotrace.txt

+4 −2
Original line number Original line Diff line number Diff line
@@ -37,7 +37,7 @@ $ echo mmiotrace > /debug/tracing/current_tracer 
$ cat /debug/tracing/trace_pipe > mydump.txt &

$ cat /debug/tracing/trace_pipe > mydump.txt &

Start X or whatever.

Start X or whatever.

$ echo "X is up" > /debug/tracing/trace_marker

$ echo "X is up" > /debug/tracing/trace_marker

$ echo none > /debug/tracing/current_tracer

$ echo nop > /debug/tracing/current_tracer

Check for lost events.

Check for lost events.
@@ -66,7 +66,7 @@ which action. It is recommended to place descriptive markers about what you 
do.

do.





Shut down mmiotrace (requires root privileges):

Shut down mmiotrace (requires root privileges):

$ echo none > /debug/tracing/current_tracer

$ echo nop > /debug/tracing/current_tracer

The 'cat' process exits. If it does not, kill it by issuing 'fg' command and

The 'cat' process exits. If it does not, kill it by issuing 'fg' command and

pressing ctrl+c.

pressing ctrl+c.
@@ -81,7 +81,9 @@ are: 
$ cat /debug/tracing/trace_entries

$ cat /debug/tracing/trace_entries

gives you a number. Approximately double this number and write it back, for

gives you a number. Approximately double this number and write it back, for

instance:

instance:

$ echo 0 > /debug/tracing/tracing_enabled

$ echo 128000 > /debug/tracing/trace_entries

$ echo 128000 > /debug/tracing/trace_entries

$ echo 1 > /debug/tracing/tracing_enabled

Then start again from the top.

Then start again from the top.





If you are doing a trace for a driver project, e.g. Nouveau, you should also

If you are doing a trace for a driver project, e.g. Nouveau, you should also