• Changbin Du's avatar
    perf ftrace: Select function/function_graph tracer automatically · eb6d31ae
    Changbin Du authored
    The '-g/-G' options have already implied function_graph tracer should be
    used instead of function tracer. So we don't need extra option
    '--tracer' in this case.
    
    This patch changes the behavior as below:
    
      - If '-g' or '-G' option is on, then function_graph tracer is used.
      - If '-T' or '-N' option is on, then function tracer is used.
      - The function_graph has priority over function tracer.
      - The option '--tracer' only take effect if neither -g/-G nor -T/-N
        is specified.
    
    Here are some examples.
    
    This will start tracing all functions using default tracer:
    
      $ sudo perf ftrace
    
    This will trace all functions using function graph tracer:
    
      $ sudo perf ftrace -G '*'
    
    This will trace function vfs_read using function graph tracer:
    
      $ sudo perf ftrace -G vfs_read
    
    This will trace function vfs_read using function tracer:
    
      $ sudo perf ftrace -T vfs_read
    
    Committer notes:
    
    Using '-h -G' will tell what that option is about, so to further clarify
    the above examples:
    
      # perf ftrace -h -G
    
        -G, --graph-funcs <func>	Set graph filter on given functions
    
      # perf ftrace -h -g
    
        -g, --nograph-funcs <func>	Set nograph filter on given functions
    
      # perf ftrace -h -T
    
        -T, --trace-funcs <func>	trace given functions only
    
      # perf ftrace -h -N
    
        -N, --notrace-funcs <func>	do not trace given functions
    
      #
    Signed-off-by: default avatarChangbin Du <changbin.du@gmail.com>
    Tested-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
    Acked-by: default avatarNamhyung Kim <namhyung@kernel.org>
    Cc: Jiri Olsa <jolsa@redhat.com>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
    Link: http://lore.kernel.org/lkml/20200808023141.14227-2-changbin.du@gmail.comSigned-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
    eb6d31ae
perf-config.txt 21.8 KB