Messages in this thread | | | Date | Mon, 5 Mar 2012 13:43:23 -0800 | From | Arun Sharma <> | Subject | Re: [PATCH] perf report: auto-detect branch stack sampling mode |
| |
On 3/5/12 12:35 PM, Arnaldo Carvalho de Melo wrote: > Em Mon, Mar 05, 2012 at 05:30:33PM +0100, Peter Zijlstra escreveu: >> On Mon, 2012-03-05 at 16:56 +0100, Ingo Molnar wrote: >>> A third usability bug is that for some reason a branch sampling >>> 'perf report' defaults to the stdio output on my testsystem - >>> with --no-branch-stack it gives the regular tui. > >> Ah, I would not have noticed that since I still explicitly build my perf >> without TUI support. That stuff mostly just gets in the way. > > Do you have any specific complaints about it? >
I think --tui code paths have some bugs that cause it to SIGSEGV, while the --stdio paths don't. I think much of it has to do with how often that particular combination of command line options is used.
Here's an example:
# perf record -ag -- sleep 3 # perf report -G -s pid --tui # SIGSEGV # perf report -G -s pid --stdio # works fine
Details attached.
-Arun
Program received signal SIGSEGV, Segmentation fault. [Switching to Thread 139975795275488 (LWP 13155)] symbol__inc_addr_samples (sym=0x91eb90, map=<value optimized out>, evidx=0, addr=120416) at util/annotate.c:73 73 util/annotate.c: No such file or directory. in util/annotate.c (gdb) bt #0 symbol__inc_addr_samples (sym=0x91eb90, map=<value optimized out>, evidx=0, addr=120416) at util/annotate.c:73 #1 0x0000000000410b5d in process_sample_event (tool=<value optimized out>, event=0x7f4ea28e26b0, sample=0x7fffcc1ca8f0, evsel=0x823ea0, machine=0x822290) at builtin-report.c:127 #2 0x00000000004433ca in flush_sample_queue (s=0x822230, tool=0x7fffcc1cc340) at util/session.c:528 #3 0x0000000000444d16 in __perf_session__process_events (session=0x822230, data_offset=<value optimized out>, data_size=<value optimized out>, file_size=<value optimized out>, tool=0x7fffcc1cc340) at util/session.c:1175 #4 0x0000000000445217 in perf_session__process_events (self=0x822230, tool=0x7fffcc1cc340) at util/session.c:1191 #5 0x000000000041015b in cmd_report (argc=0, argv=0x7fffcc1cc830, prefix=<value optimized out>) at builtin-report.c:311 #6 0x00000000004051b9 in handle_internal_command (argc=4, argv=0x7fffcc1cc830) at perf.c:273 #7 0x0000000000405623 in main (argc=4, argv=0x479218) at perf.c:388 (gdb) p /x sym->start $5 = 0xffffffff8100fb74 (gdb) p /x addr $6 = 0x1d660 (gdb) p offset $7 = 2130762476
54 int symbol__inc_addr_samples(struct symbol *sym, struct map *map, 55 int evidx, u64 addr) 56 { 57 unsigned offset; 58 struct annotation *notes; 59 struct sym_hist *h; 60 61 notes = symbol__annotation(sym); 62 if (notes->src == NULL) 63 return -ENOMEM; 64 65 pr_debug3("%s: addr=%#" PRIx64 "\n", __func__, map->unmap_ip(map, addr)); 66 67 if (addr >= sym->end) 68 return 0; 69 70 offset = addr - sym->start; 71 h = annotation__histogram(notes, evidx); 72 h->sum++; 73 h->addr[offset]++; <-- potential bad memory reference
| |