Manual: trace-cmd-show

TRACE-CMD-SHOW(1)				      libtracefs Manual					   TRACE-CMD-SHOW(1)

NAME
       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.

       --buffer_subbuf_size
	   Show the size in kilobytes of the sub-buffers of the ring buffer. The ring buffer is broken up into equal size
	   sub-buffers were an event can only be as big as the sub-buffer data section (the size minus its meta data).

       --buffer_percent
	   Show the percentage the buffer must be filled before a reader that is blocked on the trace_pipe_raw file will be
	   woken up.

	       0       : wake up immediately on any new data
	       1 - 99  : wake up on this percentage of the sub-buffers being full
	       100     : wake up after the buffer is full and the writer is on the last sub-buffer

       --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.

       --hist [system:]event
	   Show the content of a histogram "hist" file for a given event

       --trigger [system:]event
	   Show the content of the "trigger" file for a given event

       --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)

AUTHOR
       Written by Steven Rostedt, 

RESOURCES
       https://git.kernel.org/pub/scm/utils/trace-cmd/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

libtracefs						 01/22/2026					   TRACE-CMD-SHOW(1)