• Changbin Du's avatar
    tracing: Fix missing return symbol in function_graph output · 1fe4293f
    Changbin Du authored
    The function_graph tracer does not show the interrupt return marker for the
    leaf entry. On leaf entries, we see an unbalanced interrupt marker (the
    interrupt was entered, but nevern left).
    
    Before:
     1)               |  SyS_write() {
     1)               |    __fdget_pos() {
     1)   0.061 us    |      __fget_light();
     1)   0.289 us    |    }
     1)               |    vfs_write() {
     1)   0.049 us    |      rw_verify_area();
     1) + 15.424 us   |      __vfs_write();
     1)   ==========> |
     1)   6.003 us    |      smp_apic_timer_interrupt();
     1)   0.055 us    |      __fsnotify_parent();
     1)   0.073 us    |      fsnotify();
     1) + 23.665 us   |    }
     1) + 24.501 us   |  }
    
    After:
     0)               |  SyS_write() {
     0)               |    __fdget_pos() {
     0)   0.052 us    |      __fget_light();
     0)   0.328 us    |    }
     0)               |    vfs_write() {
     0)   0.057 us    |      rw_verify_area();
     0)               |      __vfs_write() {
     0)   ==========> |
     0)   8.548 us    |      smp_apic_timer_interrupt();
     0)   <========== |
     0) + 36.507 us   |      } /* __vfs_write */
     0)   0.049 us    |      __fsnotify_parent();
     0)   0.066 us    |      fsnotify();
     0) + 50.064 us   |    }
     0) + 50.952 us   |  }
    
    Link: http://lkml.kernel.org/r/1517413729-20411-1-git-send-email-changbin.du@intel.com
    
    Cc: stable@vger.kernel.org
    Fixes: f8b755ac ("tracing/function-graph-tracer: Output arrows signal on hardirq call/return")
    Signed-off-by: default avatarChangbin Du <changbin.du@intel.com>
    Signed-off-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
    1fe4293f
trace_functions_graph.c 38.4 KB