$ cat /debug/tracing/trace_pipe > mydump.txt &
Start X or whatever.
$ echo "X is up" > /debug/tracing/trace_marker
-$ echo none > /debug/tracing/current_tracer
+$ echo nop > /debug/tracing/current_tracer
Check for lost events.
do.
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
pressing ctrl+c.
events were lost, the trace is incomplete. You should enlarge the buffers and
try again. Buffers are enlarged by first seeing how large the current buffers
are:
-$ cat /debug/tracing/trace_entries
+$ cat /debug/tracing/buffer_size_kb
gives you a number. Approximately double this number and write it back, for
instance:
-$ echo 128000 > /debug/tracing/trace_entries
+$ echo 128000 > /debug/tracing/buffer_size_kb
Then start again from the top.
If you are doing a trace for a driver project, e.g. Nouveau, you should also