Subject: Re: linux support for freescale e5500 core?

From: Chris Friesen <[email-masked]>
Date: Thu, 16 Sep 2010 15:44:37 -0600

On 09/16/2010 03:39 PM, Scott Wood wrote:
> On Thu, 16 Sep 2010 14:06:37 -0600
> Chris Friesen <[email-masked]> wrote:
> 
>> We're looking at maybe doing some work with an e5500-based system.  Is
>> there any support existing/planned for this core?
> 
> Check with whoever you'd be getting the hardware from about a BSP.
> 
> And yes, it should be supported upstream at some point.

We haven't settled on a vendor yet, so I was just wondering in general
what the story was around support.

>> Also, do we know what the cache line size is--we have some legacy apps
>> that assume 32-byte.
> 
> The cache line is 64 bytes.  As with e500mc, there is a "dcbz32" mode
> for compatibility, though you probably lose much of the performance
> benefit of dcbz, and it might upset other software that properly checks
> for the cache line size but doesn't use dcbzl.

Right.  We currently use a 970-series cpu and have implemented a
per-process flag to indicate whether 32-byte mode is needed or not.
We'd have to do something similar with the new cpu.

One last question--can you comment on the speed of an e5500 relative to
a 970 for integer operations?

Thanks,

Chris

-- 
Chris Friesen
Software Developer
GENBAND
[email-masked]
www.genband.com