Re: Avoid stack frame setup in performance critical routines using tail calls

Hi,

On Mon, Jul 19, 2021, at 23:53, David Rowley wrote:
> On Tue, 20 Jul 2021 at 18:17, Andres Freund <andres@anarazel.de> wrote:
> > Any chance you could show a `perf annotate AllocSetAlloc` and `perf annotate
> > palloc` from a patched run? And perhaps how high their percentages of the
> > total work are. E.g. using something like
> > perf report -g none|grep -E 'AllocSetAlloc|palloc|MemoryContextAlloc|pfree'
> 
> Sure. See attached.
> 
> David
> 
> Attachments:
> * AllocateSetAlloc.txt
> * palloc.txt
> * percent.txt

Huh, that's interesting. You have some control flow enforcement stuff turned on (the endbr64). And it looks like it has
anon zero cost (or maybe it's just skid). Did you enable that intentionally? If not, what compiler/version/distro is
it?I think at least on GCC that's -fcf-protection=...
 

Andres