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Re: [announce] [patch] limiting IRQ load, irq-rewrite-2.4.11-B5

To: Robert Olsson <Robert.Olsson@xxxxxxxxxxx>
Subject: Re: [announce] [patch] limiting IRQ load, irq-rewrite-2.4.11-B5
From: Andreas Dilger <adilger@xxxxxxxxxxxxx>
Date: Tue, 2 Oct 2001 13:46:17 -0600
Cc: Ben Greear <greearb@xxxxxxxxxxxxxxx>, Benjamin LaHaise <bcrl@xxxxxxxxxx>, jamal <hadi@xxxxxxxxxx>, linux-kernel@xxxxxxxxxxxxxxx, kuznet@xxxxxxxxxxxxx, Ingo Molnar <mingo@xxxxxxx>, netdev@xxxxxxxxxxx
In-reply-to: <15289.62283.695135.525478@xxxxxxxxxxxx>
Mail-followup-to: Robert Olsson <Robert.Olsson@xxxxxxxxxxx>, Ben Greear <greearb@xxxxxxxxxxxxxxx>, Benjamin LaHaise <bcrl@xxxxxxxxxx>, jamal <hadi@xxxxxxxxxx>, linux-kernel@xxxxxxxxxxxxxxx, kuznet@xxxxxxxxxxxxx, Ingo Molnar <mingo@xxxxxxx>, netdev@xxxxxxxxxxx
References: <20011001210445.D15341@xxxxxxxxxx> <Pine.GSO.4.30.0110012127410.28105-100000@xxxxxxxxxxxxxxxx> <20011002011351.A20025@xxxxxxxxxx> <3BB956D3.AE0FCC54@xxxxxxxxxxxxxxx> <15289.62283.695135.525478@xxxxxxxxxxxx>
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On Oct 02, 2001  19:03 +0200, Robert Olsson wrote:
> Jamal mentioned some about the polling efforts for Linux. I can give some
> experimental data here with GIGE. Motivation, implantation etc is in paper 
> to presented at USENIX Oakland. 

How do you determine the polling rate?  I take it that this is a different
patch than Ingo's?

> Iface   MTU Met  RX-OK RX-ERR RX-DRP RX-OVR  TX-OK TX-ERR TX-DRP TX-OVR Flags
> eth0   1500   0 4031309 7803725 7803725 5968699    22     0      0      0 BRU
> eth1   1500   0     18      0      0      0 4031305      0      0      0 BRU
> 
> The RX-ERR, RX-DRP are bugs from the e1000 driver. Anyway we getting 40% of 
> packet storm routed. With a estimated throughput is about 350.000 p/s 

Are you sure they are "bugs" and not dropped packets?  It seems to me that
RX-ERR == RX-DRP, which would seem to me that the receive buffers are full
on the card and are not being emptied quickly enough (or maybe that is
indicated by RX-OVR...)  I don't know whether it is _possible_ to empty
the buffers quickly enough, I suppose CPU usage info would also shed some
light on that.

Cheers, Andreas
--
Andreas Dilger  \ "If a man ate a pound of pasta and a pound of antipasto,
                 \  would they cancel out, leaving him still hungry?"
http://www-mddsp.enel.ucalgary.ca/People/adilger/               -- Dogbert


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