[Mimedefang] Embedded Perl

[Dianne Skoll]

On Mon, 21 Sep 2015 18:53:04 -0400
"Bill Cole" <mdlist-20140424 at billmail.scconsult.com> wrote:

> As MD & Perl have matured and systems have gotten much bigger and
> much faster it has become less of a burden to just fork and exec
> fully independent slaves and let them live a very long time, so it
> is somewhat questionable whether embedding Perl is valuable to very
> many users. At a scale of hundreds of messages per minute on a
> single slow CPU it could be indispensable, but few systems have that
> sort of challenge.

Well... in theory, embedded Perl can also save memory because by not
execing an external program, the child processes can share memory pages
as long as no-one writes to them.  In practice, this isn't very effective
because Perl uses reference-counting to implment its garbage collector,
so even so-called "read-only" data gets touched as references to it are
added and deleted when variables come into and go out of scope.

My personal opinion is similar to Bill Cole's, except I'd phrase it as:

"It can't hurt.  It might help a little bit.  But it probably won't make
all that much difference."

FWIW, we do run a fairly busy scanning cluster that peaks around
11 million messages/day (~127/second or so) and we do use embedded
Perl.  A given machine in the cluster might peak at 3 million/day.

Regards,

Dianne.