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Date:      Tue, 16 Jul 1996 19:35:50 -0700
From:      David Greenman <davidg@root.com>
To:        Blair Schmittel <blair@cyber-naut.com>
Cc:        questions@freebsd.org
Subject:   Re: FreeBSD box talking slowly 
Message-ID:  <199607170235.TAA09056@root.com>
In-Reply-To: Your message of "Tue, 16 Jul 1996 14:32:37 MDT." <199607162032.OAA17233@strech.cyber-naut.com> 

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>At 12:18 AM 7/16/96 -0700, you wrote:
>>>Hello;
>>>
>>>I have a FreeBSD 2.1R box with a 3Com card in it.  When I ping from it or to
>>> it, I get pathetic ping times, such as 549.06.  When I ping from another
>>> FreeBSD box to any other computer I get ping times of about 0.880.
>>>
>>>What would cause one of my boxes to ping so slowly?  When I telnet from it to
>>> another host, it is also very slow.  Both FreeBSD boxes are on the same
>>> ethernet, one works fine, while the other is horribly slow.  I've checked
>>> the calbes, etc. they seem to work fine.
>>
>>   This can happen if you don't have the irq set correctly for the card. Check
>>that the irq setting in the kernel matches the setting on the card.
>
>
>That's not the problem..

   It's definately an interrupt related problem (or a defective card).

>  Get this, if I let ping run, each ping decreases
>in time by 10ms.  It starts at about 170ms, then goes to about 10ms after
>several pings.  After 10ms, it jumps up to 1,000ms.  It still talks slow.  I
>checked the IRQ and the card matches the kernel, I disabled every device
>which used IRQ 10 also, nothing seems to help...

   This is happening because the ep driver has a 1 second timer set that will
check for incoming packets even if it didn't get an interrupt from the card.
The timer goes off every second, so when your ping responses happen to come
in close to the timer expiration, the round-trip time is low. When they just
miss the timer, it's close to 1 second before the timer goes off again.

-DG

David Greenman
Core-team/Principal Architect, The FreeBSD Project



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