trace-cmd-show — show the contents of the Ftrace Linux kernel tracing buffer.
Synopsis
trace-cmd show [Options]
Description
The trace-cmd(1) show displays the contents of one of the Ftrace Linux kernel tracing files: trace, snapshot, or trace_pipe. It is basically the equivalent of doing:
cat /sys/kernel/debug/tracing/trace
Options
- -p
-
Instead of displaying the contents of the "trace" file, use the "trace_pipe" file. The difference between the two is that the "trace" file is static. That is, if tracing is stopped, the "trace" file will show the same contents each time.
The "trace_pipe" file is a consuming read, where a read of the file will consume the output of what was read and it will not read the same thing a second time even if tracing is stopped. This file als will block. If no data is available, trace-cmd show will stop and wait for data to appear.
- -s
Instead of reading the "trace" file, read the snapshot file. The snapshot is made by an application writing into it and the kernel will perform as swap between the currently active buffer and the current snapshot buffer. If no more swaps are made, the snapshot will remain static. This is not a consuming read.
- -c cpu
Read only the trace file for a specified CPU.
- -f
Display the full path name of the file that is being displayed.
- -B buf
If a buffer instance was created, then the -B option will access the files associated with the given buffer.
- --tracing_on
Show if tracing is on for the given instance.
- --current_tracer
Show what the current tracer is.
- --buffer_size
Show the current buffer size (per-cpu)
- --buffer_total_size
Show the total size of all buffers.
- --ftrace_filter
Show what function filters are set.
- --ftrace_notrace
Show what function disabled filters are set.
- --ftrace_pid
Show the PIDs the function tracer is limited to (if any).
- --graph_function
Show the functions that will be graphed.
- --graph_notrace
Show the functions that will not be graphed.
- --cpumask
Show the mask of CPUs that tracing will trace.
See Also
trace-cmd(1), trace-cmd-record(1), trace-cmd-report(1), trace-cmd-start(1), trace-cmd-extract(1), trace-cmd-reset(1), trace-cmd-split(1), trace-cmd-list(1), trace-cmd-listen(1)
Resources
git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/trace-cmd.git
Copying
Copyright (C) 2010 Red Hat, Inc. Free use of this software is granted under the terms of the GNU Public License (GPL).
Notes
- 1.
rostedt@goodmis.org
mailto:rostedt@goodmis.org