Messages in this thread Patch in this message | | | Date | Fri, 19 Apr 2013 10:46:55 -0400 | From | "Frank Ch. Eigler" <> | Subject | Re: systemtap broken by removal of register_timer_hook |
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Hi, Frederic -
> > How about this? > > > > Author: Frank Ch. Eigler <fche@redhat.com> > > Date: Wed Apr 3 10:35:21 2013 -0400 > > > > profiling: add profile_tick tracepoint > > [...]
> It would be better not to tie this to CONFIG_PROFILING. > A tracepoint in update_process_times() instead would be great but it's > sometimes called several times in a tick from some archs. > Probably we need something like: > > static inline tick_trace(struct pt_regs *regs) > { > trace_timer_tick(regs); > profile_tick(CPU_PROFILING); > }
I looked into this, but found no natural place to define such an inline function from which to call into a tracepoint, without having to #include the <event/FOO.h> file many times. Nor does it seem appropriate to do the identical #define CREATE_TRACE_POINTS part from all the different arch/.../*.c files that may call into that inline. If you'd like to stick to this idea, please advise further where you think the tracepoint definition & declarations should go.
In the alternative, here is v2 of the patch, just changing the tracepoint-printing argument as suggested by jistone.
- FChE
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Author: Frank Ch. Eigler <fche@redhat.com> Date: Wed Apr 3 10:35:21 2013 -0400
profiling: add profile_tick tracepoint Commit ba6fdda4 removed the timer_hook mechanism for modules to listen to profiling timer ticks (without having to set up more complicated perf mechanisms). To reduce the impact on out-of-tree users such as systemtap, a TRACE_EVENT-flavoured tracepoint is added in its place. Tested with perf and systemtap. Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Mel Gorman <mgorman@suse.de> Signed-off-by: Frank Ch. Eigler <fche@redhat.com>
diff --git a/include/trace/events/profile.h b/include/trace/events/profile.h new file mode 100644 index 0000000..445aee7 --- /dev/null +++ b/include/trace/events/profile.h @@ -0,0 +1,37 @@ +#undef TRACE_SYSTEM +#define TRACE_SYSTEM profile + +#if !defined(_TRACE_PROFILE_H) || defined(TRACE_HEADER_MULTI_READ) +#define _TRACE_PROFILE_H + +#include <linux/tracepoint.h> + + +struct pt_regs; + +/** + * profile_tick - called when the profiling timer ticks + * @type: profiling tick type, generally @CPU_PROFILING + * @regs: pointer to struct pt_regs* + */ + +TRACE_EVENT(profile_tick, + TP_PROTO(int type, struct pt_regs *regs), + TP_ARGS(type, regs), + TP_STRUCT__entry( + __field( int, type ) + __field( struct pt_regs*, regs ) + ), + TP_fast_assign( + __entry->type = type; + __entry->regs = regs; + ), + TP_printk("type=%d ip=%p", __entry->type, + instruction_pointer(__entry->regs)) +); + + +#endif /* _TRACE_PROFILE_H */ + +/* This part must be outside protection */ +#include <trace/define_trace.h> diff --git a/kernel/profile.c b/kernel/profile.c index dc3384e..d61f921 100644 --- a/kernel/profile.c +++ b/kernel/profile.c @@ -29,6 +29,9 @@ #include <asm/irq_regs.h> #include <asm/ptrace.h> +#define CREATE_TRACE_POINTS +#include <trace/events/profile.h> + struct profile_hit { u32 pc, hits; }; @@ -414,6 +417,8 @@ void profile_tick(int type) { struct pt_regs *regs = get_irq_regs(); + trace_profile_tick(type, regs); + if (!user_mode(regs) && prof_cpu_mask != NULL && cpumask_test_cpu(smp_processor_id(), prof_cpu_mask)) profile_hit(type, (void *)profile_pc(regs));
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