Re: MPC8313 performance evaluation

[Kumar Gala <galak@kernel.crashing.org>]

On Aug 6, 2009, at 1:00 PM, Lutz Jaenicke wrote:

> Hi!
>
> I am currently evaluating the performance of the MPC8313E for firewall
> (and VPN) purposes.
> The results obtained do not match my expectations so I would be  
> interested
> in some discussion.
>
> Test setup:
> -----------
> A linux 2.6.27 based firewall software is used. The software is the
> same among
> To be replaced: IXP42x custom made board (266MHz and 533MHz)
> * MPC8343 custom made board (400MHz)
> * MPC8313E-RDB Rev. C (333/333)
> As a software firewall the throughput is determined by looking into
> the routing information and IP headers, hence the performance is best
> characterized by "frames/s" which is constant over the frame size
> (as long as no limit is hit like the 100Mbit/s limit on the IXP42x).
>
> With the MPC8343@400MHz I get a throughput of approx. 24500 frames/s
> using the predefined firewall rules.
> With the MPC8313 I get a significantly lower value:
> MPC8313@250MHz          12500fps
> MPC8313@333MHz          14500fps
> MPC8313@416MHz          15500fps      (333MHz type, overclocked)
> Kernel 2.6.27 with SKB recycling from later versions and the
> e300c2/c3/c4 TLB errata workaround. Some pure computational benchmark
> with small footprint (namely "openssl speed") which should fit into
> the cache size indicates the perfect 3/4/5 ratio used.
>
> Some discussion with the the freescale rep. lead to the CSB frequency
> of the 8313 (166MHz) being significantly lower than that of the 8343.
> Is the CSB the critical point here?
> Note: the IXP42x uses an internal bus speed of 133MHz and operates
> at frame rates similar to the 8343...
>
> Does anybody else have numbers for a firewall scenario using 8313
> and/or other processors of the family?
>
> Best regards,
> 	Lutz
> PS: Yes, I know that absolute numbers will be hard to compare with
> other scenarios but relative values would be quite interesting as
> well.

What DDR frequencies (and width) are you running the 8343 vs 8313 at.   
This can have a significant impact on performance.

- k