Re: AMD Geode GX/LX Support (Refreshed)

["John Zulauf" <john.zulauf@amd.com>]

Alan,

I've done the benchmarking of the 3DNOW and non-3DNOW configured Geode
GX/LX.  This was done by extracting the kernel memcpy code into a
userland test application.  Time measurement were made using rdtsc.

The results are averaged over 4 test runs on a Geode LX. The tot_memcpy
is the total CPU clocks to run every memcpy from len = 2
through 4095 four times.  For the 3DNOW version this even includes the 

if (len <512){  __memcpy ... } 

escape found in the kernel __memcpy3d mmx_memcpy wrapper function. 

               No 3DNOW w/ 3DNOW  improvement
tot_memcpy      4635754 4360040  5.9%
tot_copy_page      2324    1853 20.3%
tot_clear_page     4398    1427 67.5%

These are meaningful improvement and the 3DNOW config should be enabled
for Geode GX and LX.

Best Regards,

John Zulauf

On Tue, 2005-11-01 at 23:53 +0000, Alan Cox wrote:
> On Maw, 2005-11-01 at 16:10 -0700, Jordan Crouse wrote:
> > in my app, I think we should leave X86_USE_PPRO_CHECKSUM enabled for Geode
> > GX/LX.
> 
> Definitely.
> 
> 
> 
> 
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John Zulauf
Senior MTS, Embedded Core Software
Advanced Micro Devices, Inc.
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