Messages in this thread | | | Date | Thu, 26 Jul 2012 19:58:46 +0200 | From | Jiri Olsa <> | Subject | Re: [PATCH 02/17] perf: Add ability to attach user level registers dump to sample |
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On Thu, Jul 26, 2012 at 07:42:55PM +0200, Stephane Eranian wrote: > On Wed, Jul 25, 2012 at 8:27 PM, Jiri Olsa <jolsa@redhat.com> wrote: > > On Wed, Jul 25, 2012 at 07:39:18PM +0200, Stephane Eranian wrote: > >> On Sun, Jul 22, 2012 at 2:14 PM, Jiri Olsa <jolsa@redhat.com> wrote: > > > > SNIP > > > >> > + if (sample_type & PERF_SAMPLE_REGS_USER) { > >> > + u64 avail = (data->regs_user != NULL); > >> > + > >> > + /* > >> > + * If there are no regs to dump, notice it through > >> > + * first u64 being zero. > >> > + */ > >> > + perf_output_put(handle, avail); > >> > + > >> The only role of avail is to report whether or not you've captured actual > >> registers. Could it be used to report the sampled process ABI (32 vs. 64) > >> instead? Something like: > >> PERF_SAMPLE_REGS_ABI_NONE -> no regs captured (emulate your > >> current behavior) > >> PERF_SAMPLE_REGS_ABI_32 -> 32 bit ABI regs captured > >> PERF_SAMPLE_REGS_ABI_64 -> 64 bit ABI regs captured > >> > >> That could help the tools interpret the register values. > > > > Yes, I think that could help once we start dealing with compat tasks. > > > You don't control whether or not you capture compat tasks. So > you have to deal with those right now. > > > The current userspace code stays untouched, because it checks for > > 'avail != 0', which stays even with your change. > > > > I think this could be sent later with all other fixes I'm already > > working on. But I can work/send it preferentially before whole patchset > > is taken if you like. > > > Well, why not do it now. You'd have to rename the available field > into something more sensible. Also need to prepare it for future > extension if they ever become necessary.
I'll send new version shortly
thanks, jirka
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