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Re: faster safe signals?

March 21, 2008 05:47
Re: faster safe signals?
Message ID:

On Friday 21 March 2008 13:35:37 Nicholas Clark wrote:
> On Fri, Mar 21, 2008 at 01:28:20PM +0100, Tels wrote:
> > On Friday 21 March 2008 13:21:53 Nicholas Clark wrote:
> > > # 3 "PERL_ASYNC_CHECK expands to"
> > > if ((my_perl->Isig_pending)) Perl_despatch_signals(my_perl)
> > >
> > > We do the check after every op. I wondered, if we did the check
> >
> > Is this check really that expensive? Or did you mean to eliminate
> > the entire call to Perl_runops_standard() for other than the
> > mentioned places?
> No, just that check. It's not expensive in itself, but it is between
> *every* op. So removing it a small code saving on every op. IIRC when
> it was added it was benchmarked, and measurable. Possibly 1 or 2
> percent?

But if you do not remove the call, just the check, then you have to 
replace that check with a check "what op is this", and I am not sure 
that will be much faster in the end (spoken like a true armchair code 

(Okay, calls in C are not as slow as calls in Perl but I'd strive to 
eliminate the call anyway. Good for the cache I guess :)

> > Btw, does Perl_runops_standard() ever return non-zero?
> I don't know. That did catch my eye. What is the return value *for*?

Don't ask me. Change it to void and see if anything complains? :)

All the best,


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