40% slowdown with dynamic /bin/sh

[Andre Guibert de Bruet]

On Mon, 24 Nov 2003, Leo Bicknell wrote:

> Process accounting can tell the story:
>
> % lastcomm | wc -l
>    47806
> % lastcomm | sed -e 's/ .*.//' | sort | uniq -c | sort -nr | head
> 25281 sendmail
> 4094 sh
> 2987 perl
> 2846 inetd
> 1704 procmail
> 1640 httpd
> 1221 cron
>  814 date
>  732 postgres
>  648 rateup
>
> Looks like sh is the 2nd most frequently executed command on my
> system.  It is 8.5% of all executed programs on this particular
> system.  I think slowing down 8.5% of all the programs the system
> runs is important.

For what it's worth, here's the data that I've taken from the daily
process accounting files of one of our somewhat busy shellboxes:

# lastcomm -f acct.0 | sed -e 's/ .*.//' | sort | uniq -c | sort -nr | head
4829 qpopper
3426 bash
3191 sendmail
1915 sh
1687 httpd
1281 sed
1030 sshd2
 952 rm
 792 procmail
 739 cron
# lastcomm -f acct.1 | sed -e 's/ .*.//' | sort | uniq -c | sort -nr | head
5383 qpopper
3282 bash
2743 sendmail
1617 httpd
1187 sh
1071 sed
 772 rm
 739 cron
 694 procmail
 478 cat
# lastcomm -f acct.2 | sed -e 's/ .*.//' | sort | uniq -c | sort -nr | head
5376 qpopper
2823 bash
2118 sendmail
1674 httpd
1510 sh
 745 procmail
 740 cron
 292 python
 288 atrun
 211 inetd

Though /bin/sh isn't 2nd on the list, it does feature prominently in the
top 10. I would assume that anyone with a fairly busy machine acting as a
shellbox and webserver would see something along these lines...

Regards,

> Andre Guibert de Bruet | Enterprise Software Consultant >
> Silicon Landmark, LLC. | http://siliconlandmark.com/    >