On Fri, Mar 13, 2015 at 06:07:34PM +0800, Wang Nan wrote: > On 2015/3/13 17:46, Namhyung Kim wrote: > > On Fri, Mar 13, 2015 at 08:41:32AM +0000, Wang Nan wrote: > >> Without this patch, perf report cause segfault if pass "" as '-t': > >> > >> $ perf report -t "" > >> > >> # To display the perf.data header info, please use > >> --header/--header-only options. > >> # > >> # Samples: 37 of event 'syscalls:sys_enter_write' > >> # Event count (approx.): 37 > >> # > >> # Children SelfCommand Shared Object Symbol > >> Segmentation fault > >> > >> This patch avoid the segfault by checking empty string for > >> 'symbol_conf.field_sep'. > > > > What about resetting it to NULL if empty string was given? > > > > In fact I'm not very clear why we need such 'symbol_conf.field_sep', so I'm > not sure whether '-t ""' is totally meanless or not. > > -t option replaces a group of character with '.' and appends them after a > field. > With -t 'abc' I get something like: > > # > # OverheadabcCommand abcShared Object abcSymbol > 100.00%abcb.beltr.ceabc[kernel.k.llsyms]abc[k] 0xffffffff810118f0 > ... > > Hard to read... > > I read docs and your commit messages, but still not understand the option. > Could you > please explain the goal and usage of that option again?
Well, I'm not the person who wrote the doc and introduced this option. ;-) Anyway AFAIK it's to generate a CSV file so usual value would be ','. To reduce possible confusion due to the separation character in the original output, it replaces the character during the generation. Thanks, Namhyung -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
