Messages in this thread | | | Date | Fri, 24 Oct 2014 15:55:10 +0200 | From | Jiri Olsa <> | Subject | Re: [PATCH V6 17/17] perf tools: choose to dump callchain from LBR and FP |
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On Fri, Oct 24, 2014 at 03:36:00PM +0200, Jiri Olsa wrote: > On Sun, Oct 19, 2014 at 05:55:12PM -0400, Kan Liang wrote: > > SNIP > > > - return 0; > > - } > > - continue; > > + mix_chain_nr = i + 2 + lbr_nr; > > + if (mix_chain_nr > PERF_MAX_STACK_DEPTH) { > > + pr_warning("corrupted callchain. skipping...\n"); > > + return 0; > > } > > > > - al.filtered = 0; > > - thread__find_addr_location(thread, machine, cpumode, > > - MAP__FUNCTION, ip, &al); > > - if (al.sym != NULL) { > > - if (sort__has_parent && !*parent && > > - symbol__match_regex(al.sym, &parent_regex)) > > - *parent = al.sym; > > - else if (have_ignore_callees && root_al && > > - symbol__match_regex(al.sym, &ignore_callees_regex)) { > > - /* Treat this symbol as the root, > > - forgetting its callees. */ > > - *root_al = al; > > - callchain_cursor_reset(&callchain_cursor); > > + for (j = 0; j < mix_chain_nr; j++) { > > + struct addr_location al; > > + > > + if (callchain_param.order == ORDER_CALLEE) { > > + if (j < i + 2) > > + ip = chain->ips[j]; > > + else > > + ip = lbr_stack->entries[j - i - 2].from; > > + } else { > > + if (j < lbr_nr) > > + ip = lbr_stack->entries[lbr_nr - j - 1].from; > > + else > > + ip = chain->ips[i + 1 - (j - lbr_nr)]; > > } > > + err = __machine__resolve_callchain_sample(machine, > > + thread, ip, &cpumode, parent, root_al, &al); > > + /* Discard all when the callchain is corrupted */ > > + if (err > 0) > > + return 0; > > + else if (err) > > + return err; > > so you print FP callchains followed by LBR stack data, right? > > but AFAICS from kernel changes the FP callchains and LBR callchains > data are unrelated.. 2 datasources of the same information > > do we rather want to print them separately? or using an option > as Andi did in his lbr-as-callgraph patchset: > http://marc.info/?l=linux-kernel&m=141177467802602&w=2
hum, sorry I've got confused by perf report -D output:
5719019682019 0x2128 [0x80]: PERF_RECORD_SAMPLE(IP, 0x2): 2499/2499: 0x401791 period: 327077 addr: 0 ... chain: nr:3 ..... 0: fffffffffffffe00 FP ..... 1: 0000000000401791 FP ..... 2: 00000032dca21d63 LBR ..... 3: 000000000040184c LBR
which sometimes displays user space FP data with LBR.. but I guess the intention was to display either userspace FP or LBR, right?
I think we should have an option to be able to choose/switch. Once general option that will tell report to use: FP, DWARF, LBR (branches), LBR (callchain)
setting by default whatever the best option is based on the data we have.
thanks, jirka
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