Messages in this thread | | | Date | Mon, 17 Sep 2012 09:11:13 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCH 3/3 v2] perf tool: give user better message if precise is not supported |
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* Peter Zijlstra <peterz@infradead.org> wrote:
> On Fri, 2012-09-14 at 22:11 +0200, Ingo Molnar wrote: > > return -EPERF_CPU_PRECISE_EV_NOTSUPP; > > I just don't like having to enumerate all possible fails, I'm > too lazy. Can't we be smarter about that? Could we do a > {reason}x{bit-offset} like thing? > > Where we limit reason to a few simple things like: > > invalid > out-of-range > not-supported > > and have the bit-offset indicate the field we're having the particular > problem with? > > Then all we need is a smart way to generate and map the bit-offsets > without too much manual labour.
Putting the 'where' into a separate field would do that, and thus we could generate and report such structured errors as well - but nevertheless there will always be special/individual errors as well that won't fit into such a scheme, for which we should include a 'boring' errno range as well ...
I.e. a {where},{what} s32 pair of fields - if 'where' is zero then 'what' is the enumerated errno value I suggested, if it's nonzero then it's the 'where' indication you suggested.
Thanks,
Ingo
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