trace-cmd-show(1) — Linux manual page


TRACE-CMD-SHOW(1)                                          TRACE-CMD-SHOW(1)

NAME         top

       trace-cmd-show - show the contents of the Ftrace Linux kernel tracing

SYNOPSIS         top

       trace-cmd show [OPTIONS]

DESCRIPTION         top

       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         top

           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.

           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.

           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.

           Show if tracing is on for the given instance.

           Show what the current tracer is.

           Show the current buffer size (per-cpu)

           Show the total size of all buffers.

           Show what function filters are set.

           Show what function disabled filters are set.

           Show the PIDs the function tracer is limited to (if any).

           Show the functions that will be graphed.

           Show the functions that will not be graphed.

           Show the mask of CPUs that tracing will trace.

SEE ALSO         top

       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         top

       Written by Steven Rostedt, <[1]>

RESOURCES         top


COPYING         top

       Copyright (C) 2010 Red Hat, Inc. Free use of this software is granted
       under the terms of the GNU Public License (GPL).

NOTES         top


COLOPHON         top

       This page is part of the trace-cmd (a front-end for Ftrace) project.
       Information about the project can be found at [unknown -- if you
       know, please contact] If you have a bug report for
       this manual page, send it to Steven Rostedt <>.
       This page was obtained from the project's upstream Git repository
       on 2020-11-01.  (At that time, the date of the most recent commit
       that was found in the repository was 2020-10-06.)  If you discover
       any rendering problems in this HTML version of the page, or you
       believe there is a better or more up-to-date source for the page, or
       you have corrections or improvements to the information in this
       COLOPHON (which is not part of the original manual page), send a mail

                                 05/27/2020                TRACE-CMD-SHOW(1)