[root@quaco ~]# perf ftrace latency -T handle_mm_fault -p `pidof firefox | sed 's/ /,/g'`
^C#   DURATION     |      COUNT | GRAPH                                          |
     0 - 1    us |       6647 | #################                              |
     1 - 2    us |       5405 | ##############                                 |
     2 - 4    us |       3389 | ########                                       |
     4 - 8    us |       1223 | ###                                            |
     8 - 16   us |        499 | #                                              |
    16 - 32   us |        164 |                                                |
    32 - 64   us |         12 |                                                |
    64 - 128  us |          3 |                                                |
   128 - 256  us |          1 |                                                |
   256 - 512  us |          0 |                                                |
   512 - 1024 us |          0 |                                                |
     1 - 2    ms |          1 |                                                |
     2 - 4    ms |          0 |                                                |
     4 - 8    ms |          0 |                                                |
     8 - 16   ms |          0 |                                                |
    16 - 32   ms |          0 |                                                |
    32 - 64   ms |          0 |                                                |
    64 - 128  ms |          0 |                                                |
   128 - 256  ms |          0 |                                                |
   256 - 512  ms |          0 |                                                |
   512 - 1024 ms |          0 |                                                |
     1 - ...   s |          0 |                                                |
[root@quaco ~]#