# trace-cmd-show

## 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.
    


## 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
    


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