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Date:      Thu, 1 Mar 2007 12:12:58 +1030
From:      "Daniel O'Connor" <doconnor@gsoft.com.au>
To:        freebsd-hackers@freebsd.org
Subject:   PCI slave performance (OT?)
Message-ID:  <200703011212.59136.doconnor@gsoft.com.au>

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Hi,
We make a custom PCI card used for transferring data from our radar system=
=20
acquisition chassis to a PC. It is rather old and we are looking at updatin=
g=20
it but I would like to try and squeeze out as much performance as possible =
to=20
satisfy our existing customers.

It is a PCI slave only device using a PLX-9051 to read data from a FIFO. Th=
is=20
means that we can't use prefetch or bursting because the PLX chip can throw=
=20
data away in these circumstances :(

Anecdotal evidence suggests that the maximum sustainable speed has dropped=
=20
when we switched from 4.x to 6.x, but we also changed from i386 to amd64 an=
d=20
used different motherboard chipsets so it's difficult to know where the=20
problem really lies.

I plan on doing some tests to try and determine what is causing the slow do=
wn=20
but I would appreciate any suggestions people may have :)

One idea I did have was to get a dual core CPU and then one core would spen=
d=20
all its time reading from the PCI bus while the other did data processing,=
=20
etc..

Any suggestions gratefully received!

=2D-=20
Daniel O'Connor software and network engineer
for Genesis Software - http://www.gsoft.com.au
"The nice thing about standards is that there
are so many of them to choose from."
  -- Andrew Tanenbaum
GPG Fingerprint - 5596 B766 97C0 0E94 4347 295E E593 DC20 7B3F CE8C

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