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Re: zerocopy results on GigE

To: Pekka Pietikainen <pp@xxxxxxxxxxxxxx>
Subject: Re: zerocopy results on GigE
From: "David S. Miller" <davem@xxxxxxxxxx>
Date: Tue, 6 Feb 2001 13:36:32 -0800 (PST)
Cc: netdev@xxxxxxxxxxx
In-reply-to: <20010206194919.A633@xxxxxxxxx>
References: <20010206194919.A633@xxxxxxxxx>
Sender: owner-netdev@xxxxxxxxxxx
Pekka Pietikainen writes:
 > Jumbo frames, sender is dual pIII/500 with 32/66 PCI, receiver a dual pII/450
 > with 32/33, both have 1MB Alteons. CPU use is measured using cyclesoak.
 > SO_RCVBUF/SO_SNDBUF set to 512k, no other sockopts touched.

Strange, cpu usage is close to nothing for sendfile cases yet full
bandwidth is not obtained.  Here is what I am getting on UltraSparc
systems:

ZC results:

2.4.2pre1+zerocopy+sendfile             acenic-->Syskonnect     120 MB/sec, 32% 
load
2.4.2pre1+zerocopy                      acenic-->Syskonnect     94 MB/sec, 52% 
load
2.4.2pre1+sendfile                      acenic-->Syskonnect     110 MB/sec, 49% 
load
2.4.2pre1                               acenic-->Syskonnect     80 MB/sec, 49% 
load

I am using the Netgear (ie. 512K memory) acenic cards as the sender.

Your idea to experiment with removing the non-zerocopy related tweaks
from the zerocopy patches may prove fruitful, please let everyone
know what you do or do not discover here.

Later,
David S. Miller
davem@xxxxxxxxxx

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