Re: Efficient x86 and x86_64 NOP microbenchmarks

[Avi Kivity]

Andi Kleen wrote:
> So for me the best strategy would be to get rid of the frame pointer
> and ignore the nops. This unfortunately would require going away
> from -pg and instead post process gcc output to insert "call mcount"
> manually. But the nice advantage of that is that you could actually 
> set up a custom table of callers built in a ELF section and with
> that you don't actually need the runtime patching (which is only
> done currently because there's no global table of mcount calls),
> but could do everything in stop_machine(). Without
> runtime patching you also don't need single part nops. 
>
> I think that would be the best option. I especially like it because
> it would prevent forcing frame pointer which seems to be costlier
> than any kinds of nosp.
>
>   

How would you deal with inlines?  Using debug information?

--
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.

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