Re: Newbie: Slow scheduling?

[Dani Pardo <dani@minerva.enpl.es>]

On Wed, 30 Jun 1999, Matti Aarnio wrote:

> 
>   Lets see what happens under ZMailer:
> 
[..]
> 
>   So, for each delivery, ZMailer does at least 13 directory MODIFYING
>   operations, moving from one directory to other is here assumed equally
>   costly to simple rename within one directory, or file creation and unlink.
[..]
>   Now I do tend to think that those directory transactions are the most
>   expensive part of the email delivery in the usual UNIX environment.
> 
>   In this sense 'sendmail' does pretty lightweight set of dirops; mere
>   6, I think (creating and deleting 3 files in 'mqueue' directory.)
> 
[..]
> 
>   That said, 5000 messages in 3*60 seconds means about 28 deliveries per
>   second, or about 360 dirops per second!  You must have very recent
>   Linux at that PPro of yours, which has asynchronous metadata..
>   (Doing same in 2*60 seconds would mean about 540 dirops per second;
>    mere 2 milliseconds per dirop ... ok, just and just possible with
>    synchronously written metadata, if the system doesn't need to actually
>    write/read file data content (all in cache), and your disks are brand
>    new speed demons, or you operate on RAMDISK..)

 Isn't it a great idea? Having the $POSTOFFICE in a ramdisk?

 Mmm.. let me see:
 (system almost idle, empty mailq)
$ time ./mailflooder.pl

real    4m43.440s
user    0m38.830s
sys     0m37.200s
$

 This real time has varied from 5 to almost 8 minutes, and I calcule(!)
one or two minutes more to deliver the rest of the mailq. Time flies
faster than I thought... anyway it's very fast.
 Killing syslogd also increases speed. 
 
>   The term you are looking for is: latency
 
 Yes, that's the word.
 Btw, another thing I like much is the policytest(). I've been trying to
use Procmail to reject spam, but most of what I could do is to send it to
/dev/null. I receive mail at 14.400baud, and it would be nicer the
ZMailer's blocking method.
 For what I've seen, I can rejet by HELO/EHLO, FROM, and TO fields. Can I
reject from other fields? I.e: if Organization matches 'spam empire' or
X-Mailer matches 'Outlook' then reject it.
 Thanks in advance,

---
Dani Pardo, dani@enpl.es
Enplater S.A