Re: FTRACE: regression in 31-rc7

[Ingo Molnar]

* Gregory Haskins <gregory.haskins@xxxxxxxxx> wrote:

> Hi Steve,
> 
> I just moved from -rc6 to -rc7, and I noticed that the 
> function-graph tracer suddenly stopped working properly: I do not 
> see any output from seeming most things except a handful of 
> interrupt related events.  I currently believe it may be an issue 
> with tracing modules.
> 
> I haven't had a chance to bisect yet, but I did confirm that 
> reverting the -rc7 merge restores the previous tracer behavior.  
> Any help/pointers appreciated.

Works fine here (using -rc7 based -tip):

 11)               |  sys_munmap() {
 11)               |    profile_munmap() {
 11)               |      blocking_notifier_call_chain() {
 11)   0.170 us    |        __blocking_notifier_call_chain();
 11)   0.480 us    |      }
 11)   0.799 us    |    }
 11)               |    down_write() {
 11)   0.146 us    |      _cond_resched();
 11)   0.146 us    |      _spin_lock_irq();
 11)   0.754 us    |    }
 11)               |    do_munmap() {
 11)   0.144 us    |      test_ti_thread_flag();
 11)   0.144 us    |      test_ti_thread_flag();
 11)   0.164 us    |      find_vma();
 11)   0.156 us    |      arch_unmap_area_topdown();
 11)               |      unmap_region() {
 11)               |        lru_add_drain() {
 11)               |          ____pagevec_lru_add() {
 11)   0.153 us    |            _spin_lock_irq();
 11)   0.145 us    |            __inc_zone_state();
 11)               |            __inc_zone_state() {
 11)   0.144 us    |            __inc_zone_state();
 11)   0.146 us    |            __inc_zone_state();
 11)   0.145 us    |            __inc_zone_state();
 11)   0.223 us    |            release_pages();
 11)   2.463 us    |          }
 11)   2.795 us    |        }
 11)               |        unmap_vmas() {
 11)               |          unmap_page_range() {
 11)   0.144 us    |            pgd_none_or_clear_bad();
 11)   0.145 us    |            pud_none_or_clear_bad();
 11)   0.154 us    |            pmd_none_or_clear_bad();
 11)               |            zap_pte_range() {
 11)   0.145 us    |              _spin_lock();
 11)   0.168 us    |              vm_normal_page();
 11)   0.143 us    |              mark_page_accessed();
 11)               |              page_remove_rmap() {
 11)               |                __dec_zone_page_state() {
 11)   0.150 us    |                  __dec_zone_state();
 11)   0.441 us    |                }
 11)   0.748 us    |              }
 11)   0.149 us    |              vm_normal_page();
 11)   0.146 us    |              mark_page_accessed();
 11)               |              page_remove_rmap() {
 11)               |                __dec_zone_page_state() {
 11)   0.148 us    |                  __dec_zone_state();
 11)   0.439 us    |                }
 11)   0.748 us    |              }
 11)   0.144 us    |              vm_normal_page();
 11)   0.148 us    |              mark_page_accessed();
 11)               |              page_remove_rmap() {
 11)               |                __dec_zone_page_state() {
 11)   0.148 us    |                  __dec_zone_state();
 11)   0.438 us    |                }
 11)   0.731 us    |              }
 11)   0.144 us    |              vm_normal_page();
 11)   0.146 us    |              mark_page_accessed();
 11)               |              page_remove_rmap() {
 11)               |                __dec_zone_page_state() {
 11)   0.146 us    |                  __dec_zone_state();
 11)   0.437 us    |                }
 11)   0.733 us    |              }
 11)   0.143 us    |              vm_normal_page();
 11)   0.148 us    |              mark_page_accessed();
 11)               |              page_remove_rmap() {
 11)               |                __dec_zone_page_state() {
 11)   0.147 us    |                  __dec_zone_state();
 11)   0.438 us    |                }
 11)   0.731 us    |              }
 11)   0.144 us    |              vm_normal_page();
 11)   0.146 us    |              mark_page_accessed();
 11)               |              page_remove_rmap() {
 11)               |                __dec_zone_page_state() {
 11)   0.146 us    |                  __dec_zone_state();
 11)   0.436 us    |                }
 11)   0.732 us    |              }
 11)   0.143 us    |              vm_normal_page();
 11)   0.146 us    |              mark_page_accessed();
 11)               |              page_remove_rmap() {
 11)               |                __dec_zone_page_state() {
 11)   0.147 us    |                  __dec_zone_state();
 11)   0.435 us    |                }
 11)   0.751 us    |              }
 11)   0.142 us    |              vm_normal_page();
 11)   0.146 us    |              mark_page_accessed();
 11)               |              page_remove_rmap() {
 11)               |                __dec_zone_page_state() {
 11)   0.146 us    |                  __dec_zone_state();
 11)   0.438 us    |                }
 11)   0.733 us    |              }
 11)   0.143 us    |              vm_normal_page();
 11)   0.145 us    |              mark_page_accessed();
 11)               |              page_remove_rmap() {
 11)               |                __dec_zone_page_state() {
 11)   0.145 us    |                  __dec_zone_state();
 11)   0.434 us    |                }
 11)   0.731 us    |              }
 11) + 14.220 us   |            }
 11) + 15.442 us   |          }
 11) + 15.750 us   |        }
 11)               |        free_pgtables() {

so it would be nice if you sent a config and a precise description 
of what you did to see the weirdness - in case others have trouble 
reproducing it as well.

	Ingo
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/