On Fri, 9 Jan 2015 09:19:04 -0500 Steven Rostedt <rostedt@xxxxxxxxxxx> wrote: > task: <...>-2880 > Event: func: __kmalloc() (74) Total: 53254 Avg: 719 Max: 1095 Min:481 I forgot to mention that all times are in nanoseconds (or whatever the trace clock is set at). > | > + ftrace_ops_list_func (0xffffffff810c229e) > 100% (74) time:53254 max:1095 min:481 avg:719 > ftrace_call (0xffffffff81526047) > trace_preempt_on (0xffffffff810d28ff) > preempt_count_sub (0xffffffff81061c62) > __mutex_lock_slowpath (0xffffffff81522807) > __kmalloc (0xffffffff811323f3) > __kmalloc (0xffffffff811323f3) The above may be a bit confusing, as the stack trace included more than it should have (it's variable and hard to get right). ftrace_ops_list_func() did not call kmalloc, but it did call the stack trace and was included. You want to look below to find the interesting data. This is still a new feature, and is using some of the kernel tracing more than it has been in the past. There's still a few eggs that need to be boiled here. > tracing_buffers_splice_read (0xffffffff810ca23e) All the kmallocs for this task was called by tracing_buffers_splice_read() (hmm, I chose to show you the trace-cmd profile on itself. If I had included "-F -c" (follow workload only) or -e sched_switch I would have known which task to look at). > | > + set_next_entity (0xffffffff81067027) > | 66% (49) time:34925 max:1044 min:481 avg:712 > | __switch_to (0xffffffff810016d7) > | trace_hardirqs_on (0xffffffff810d28db) > | _raw_spin_unlock_irq (0xffffffff81523a8e) > | trace_preempt_on (0xffffffff810d28ff) > | preempt_count_sub (0xffffffff81061c62) > | __schedule (0xffffffff815204d3) > | trace_preempt_on (0xffffffff810d28ff) > | buffer_spd_release (0xffffffff810c91fd) > | SyS_splice (0xffffffff8115dccf) > | system_call_fastpath (0xffffffff81523f92) > | > + do_read_fault.isra.74 (0xffffffff8111431d) I'm not sure how much I trust this. I don't have FRAME_POINTERS enabled, so the stack traces may not be as accurate. But you get the idea, and this can show you where the slow paths lie. -- Steve > | 24% (18) time:12654 max:1008 min:481 avg:703 > | | > | + select_task_rq_fair (0xffffffff81067806) > | | 89% (16) time:11234 max:1008 min:481 avg:702 > | | trace_preempt_on (0xffffffff810d28ff) > | | buffer_spd_release (0xffffffff810c91fd) > | | SyS_splice (0xffffffff8115dccf) > | | system_call_fastpath (0xffffffff81523f92) > | | > | + handle_mm_fault (0xffffffff81114df4) > | 11% (2) time:1420 max:879 min:541 avg:710 > | trace_preempt_on (0xffffffff810d28ff) > | buffer_spd_release (0xffffffff810c91fd) > | SyS_splice (0xffffffff8115dccf) > | system_call_fastpath (0xffffffff81523f92) > | > | > | > + update_stats_wait_end (0xffffffff81066c5c) > | 6% (4) time:3153 max:1095 min:635 avg:788 > | set_next_entity (0xffffffff81067027) > | __switch_to (0xffffffff810016d7) > | trace_hardirqs_on (0xffffffff810d28db) > | _raw_spin_unlock_irq (0xffffffff81523a8e) > | trace_preempt_on (0xffffffff810d28ff) > | preempt_count_sub (0xffffffff81061c62) > | __schedule (0xffffffff815204d3) > | trace_preempt_on (0xffffffff810d28ff) > | buffer_spd_release (0xffffffff810c91fd) > | SyS_splice (0xffffffff8115dccf) > | system_call_fastpath (0xffffffff81523f92) > | > + _raw_spin_unlock (0xffffffff81523af5) > | 3% (2) time:1854 max:936 min:918 avg:927 > | do_read_fault.isra.74 (0xffffffff8111431d) > | handle_mm_fault (0xffffffff81114df4) > | buffer_spd_release (0xffffffff810c91fd) > | SyS_splice (0xffffffff8115dccf) > | system_call_fastpath (0xffffffff81523f92) > | > + trace_hardirqs_off (0xffffffff810d2891) > 1% (1) time:668 max:668 min:668 avg:668 > kmem_cache_free (0xffffffff81130e48) > __dequeue_signal (0xffffffff8104c802) > trace_preempt_on (0xffffffff810d28ff) > preempt_count_sub (0xffffffff81061c62) > _raw_spin_unlock_irq (0xffffffff81523a8e) > recalc_sigpending (0xffffffff8104c5d1) > __set_task_blocked (0xffffffff8104cd2e) > trace_preempt_on (0xffffffff810d28ff) > preempt_count_sub (0xffffffff81061c62) > preempt_count_sub (0xffffffff81061c62) > buffer_spd_release (0xffffffff810c91fd) > SyS_splice (0xffffffff8115dccf) > system_call_fastpath (0xffffffff81523f92) > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>