Re: Advice Required - for avoiding conflict betwen qmail-smtpd, rblsmtpd loaded as shared objects in tcpserver

* Jens Bauer <[email protected]> [2017-04-02 21:43]:
> On Sun, 2 Apr 2017 09:17:16 -0600, Charles Cazabon wrote:
> > I'm afraid you're fooling yourself.  Any control files that are opened and
> > read regularly - i.e. if you're getting at least a few SMTP 
> > connections every minute - will be satisfied from the cache.
> On most linux systems it might, but these days things are different.

wrong, that is true for any halfway modern OS.

> You can run qmail under Linux or UNIX, but you might use a system, which does not have much memory to run your qmail.
> If that's the case, the file cache might not be very efficient (or it might be disabled).

then you fix this OS problem at the OS level.

you don't build new sidewalks because somebody's shoes might be worn out.

> If you're developing on a system which has all the great features,
> performance testing might not show the right results in cases where
> "low-end" systems are used. 

then test on slow hardware too.

hint: fork is not your problem, nor is reading config files.

> If memory is no longer duplicated to a new buffer on each read (from the cache), then it will certainly be a performance boost:

whether there is duplication or not is OS-dependent. and even if: this
won't be your bottleneck.

>  * more memory will be available.

nope. please learn how virtual memory works on prettyy much everything
since at least 4.4BSD.

>  * less time will be spent looking for a free block of memory.

between "nope" and "not even measurable".

> Also, the PowerPC based Macs have some serious problems with locks,
> mutexes, spinlocks, etc; it may wait forever (I've seen up to 2
> minutes) until it can access files (Yes, that's a flaw/bug/error in the
> system, but it will never be corrected along with thousands of other
> bugs, since Apple do not support old systems anymore). 

so don't run old broken sh*t.
and even more important: don't screw up userland software to work
around old broken obsolete OSes.

Charles is right. You two are on the wrong train.

-- 
Henning Brauer, [email protected], [email protected]
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