trace-cmd-show(1) — Linux manual page


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

NAME         top

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

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

       -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 
       ⟨⟩.  If you have a bug report for this
       manual page, see ⟨⟩.  This page was
       obtained from the project's upstream Git repository
       ⟨⟩ on
       2023-06-23.  (At that time, the date of the most recent commit
       that was found in the repository was 2023-06-07.)  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 to

libtracefs                     06/22/2023              TRACE-CMD-SHOW(1)