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Date:      Wed, 29 Jan 1997 22:03:50 +0100
From:      j@uriah.heep.sax.de (J Wunsch)
To:        Shimon@i-Connect.Net (Simon Shapiro)
Cc:        hackers@FreeBSD.ORG
Subject:   Re: More 2.2-BETA goodies...
Message-ID:  <Mutt.19970129220350.j@uriah.heep.sax.de>
In-Reply-To: <XFMail.970129120959.Shimon@i-Connect.Net>; from Simon Shapiro on Jan 29, 1997 11:13:14 -0800
References:  <XFMail.970129120959.Shimon@i-Connect.Net>

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As Simon Shapiro wrote:

> 1.  An easy way to panic the system:
> 
>     * Put ``devfs           /devs                   devfs   rw 0 0''
>       in /etc/fstab
>     * Do ``mount -a''

Shortcut: umount /devs

Known sucker.  DEVFS is really not yet ready for the masses.  (Alas.)

> 5.  Question:  Using xperfmon++ (cool), one observes that a system equipped
>     with AHA2940W enjoys about 3-15 times as many interrupts/sec as disk 
>     transfers/sec.  The system, does nothing but SCSI right now (cvs
>     checkout in parallel with a tape backup (cpio, I know...).
>     Nothing else.
> 
>       Discounting
>     100 interrupts for the heartbeat, ...

You have to discount 100 + 128 interrupts per second, there are two
clocks.  If you're using pcaudio, this increases to 100 + 1024 while
pcaudio is running.

xperfmon++ has a tendency to not become adapted to more recent changes
very quickly (guess whom you should blame for this :-).  systat
-vmstat might be more authoritative in its data (and also gives you a
split view for the various interrupt sources).

-- 
cheers, J"org

joerg_wunsch@uriah.heep.sax.de -- http://www.sax.de/~joerg/ -- NIC: JW11-RIPE
Never trust an operating system you don't have sources for. ;-)



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