The open opcode

[Allison Randal]

On 4/23/10 3:17 AM, Geoffrey Broadwell wrote:
>
> Honest question: How did this ever turn up as a performance issue?  Was
> this a response to performance problems before the PCC
> refactoring/optimization?
>
> I'm trying to imagine a case (even a completely contrived one) in which
> the addition of a PCC call during the file open operation becomes a
> bottleneck, and I'm afraid I'm failing, unless I've grossly
> underestimated the cost of a PCC call in my calculations ....

I was surprised too. Before the I/O refactor year before last, chromatic 
and I had a running gag about I/O optimizations: "The slowest thing 
about I/O is... I/O."

Turns out, that's not true. If you load I/O down with a pile of PCC 
method invocations, you can slow it down. Substantially.

Allison