On Fri, 2013-12-27 at 15:54 +0100, Jean-Jacques Hiblot wrote: > Hi Tom, Steven, > > I'm currently doing some tests with the event triggers > (git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git > for-next). > At the moment I can't use event triggers with probes dynamically > created (with perf probe or via > /sys/kernel/debug/tracing/kprobe_events) > Predefined probes like > /sys/kernel/debug/tracing/events/kmem/kmalloc/trigger are working > fine. > Am I missing something ? >
No, it's just that kprobes hasn't been hooked up yet to actually invoke the triggers. Let me look at doing that over the weekend... Tom > example: > > ---------------------------------------------------------------- > with a predefined probe > ---------------------------------------------------------------- > > prompt> echo 'stacktrace' > > /sys/kernel/debug/tracing/events/kmem/kmalloc/trigger > prompt> ls > prompt> cat /sys/kernel/debug/tracing/trace > # tracer: nop > # > # entries-in-buffer/entries-written: 14/14 #P:1 > # > # _-----=> irqs-off > # / _----=> need-resched > # | / _---=> hardirq/softirq > # || / _--=> preempt-depth > # ||| / delay > # TASK-PID CPU# |||| TIMESTAMP FUNCTION > # | | | |||| | | > ls-971 [000] .... 298.050000: <stack trace> > => ftrace_raw_event_kmem_alloc > => kmem_cache_alloc_trace > => do_execve > => SyS_execve > => ret_fast_syscall > ls-971 [000] .... 298.050000: <stack trace> > => ftrace_raw_event_kmem_alloc > => kmem_cache_alloc_trace > => load_elf_binary > [...] > > ---------------------------------------------------------------- > with a dynamically defined probe > ---------------------------------------------------------------- > > prompt> perf probe -a in_kmalloc=__kmalloc > prompt> echo 'stacktrace' > > /sys/kernel/debug/tracing/events/probe/in_kmalloc/trigger > prompt> perf record -e probe:in_kmalloc -aR sleep 10& > [... do something here ...] > prompt> perf report > [...] > # Samples: 24 of event 'probe:in_kmalloc' > # Event count (approx.): 24 > # > # Overhead Command Shared Object Symbol > # ........ ....... ................. ............. > # > 50.00% ls [kernel.kallsyms] [k] __kmalloc > 12.50% sleep [kernel.kallsyms] [k] __kmalloc > 12.50% sh [kernel.kallsyms] [k] __kmalloc > 12.50% perf [kernel.kallsyms] [k] __kmalloc > 12.50% more [kernel.kallsyms] [k] __kmalloc > [...] > > prompt> cat /sys/kernel/debug/tracing/trace > # tracer: nop > # > # entries-in-buffer/entries-written: 0/0 #P:1 > # > # _-----=> irqs-off > # / _----=> need-resched > # | / _---=> hardirq/softirq > # || / _--=> preempt-depth > # random: nonblocking pool is initialized > ||| / delay > # TASK-PID CPU# |||| TIMESTAMP FUNCTION > # | | | |||| | | -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
