Messages in this thread | | | Date | Wed, 10 Nov 2010 16:00:25 +0100 | From | Frederic Weisbecker <> | Subject | Re: [PATCH 1/2] tracing,mm - add kernel pagefault tracepoint for x86 & x86_64 |
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On Wed, Nov 10, 2010 at 02:52:44PM +0100, Ingo Molnar wrote: > > * Jiri Olsa <jolsa@redhat.com> wrote: > > > On Wed, Nov 10, 2010 at 08:29:54AM -0500, Christoph Hellwig wrote: > > > On Wed, Nov 10, 2010 at 12:56:11PM +0100, Jiri Olsa wrote: > > > > + TP_printk("task=%lx, address=%lx, regs=%lx", > > > > + (unsigned long)__entry->task, (unsigned long)__entry->address, > > > > + __entry->regs) > > > > > > How exactly do you use the information in this trace point? Especially > > > the undecoded pt_regs doesn't seem very useful to me at all. > > > > agreed, the registers pointer are not very useful in the trace file output, > > and could be taken away.. just wanted to be complete I guess > > > > but I believe they are useful when you register the mm_kernel_pagefault > > tracepoint and process the information by yourself > > That would be expressed in a better and more generic fashion via adding > PERF_SAMPLE_REGS to perf_event_sample_format, and add a ptregs dump in > kernel/perf_event.c, perf_output_sample(). That way any tracepoint can request a > (user-space)ptregs state snapshot, not just the pagefault ones. > > Thanks, > > Ingo
We are going to have that with the dwarf based callchain patchset. I'm cooking this.
Thanks.
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