Re: [microblaze-uclinux] OT?, Performance

[Goran Bilski <Goran.Bilski@xxxxxxxxxx>]

Hi,

I think I need to explain what DMIPS stands for.

Dhrystone is a benchmark that you measure how many times can you loop in 
a second.

A VAX 780 could do 1757 iterations/s.
This is what is called 1 DMIPS.

 From the numbers that I have seen in the thread here, MicroBlaze could 
do 5035 iterations/s => 2.8 DMIPS which would happen when running 
without caches on a slow external memory.
Someone else turn on the caches and got 56529.1 iterations/s => 
(56529.1/1757) DMIPS => 32 DMIPS which is more what to expect from 
external memory.

The DMIPS number that xilinx has reported is when running from internal 
memories.

Take a look at this link for more information on Dhrystone.

http://netlib2.cs.utk.edu/performance/html/dhrystone.intro.html

Göran
John Williams wrote:

> Yasushi SHOJI wrote:
>
>> Hi all,
>>
>> # This must be OT for mb-uclinux ml.
>
>
> Maybe not, the very fact that we are using linux on an FPGA makes 
> these philosophical questions worth asking (and possible to be answered!)
>
>> say, if we have perfect C to RTL or HDL compiler, would it be
>> impractical to build not only web server but entire uclinux kernel and
>> userland purely from logic?
>>
>> I have been wondering a few days.  what will stop us?
>
>
> Now I *will* get off topic :)
>
> I'm not convinced that we will ever be able to run the source for, 
> say, the boa webserver, through a translator, and get some detailed 
> low level RTL circuit to synthesise.  What does malloc() mean in 
> hardware?
>
> Well maybe that's not true, if you give me the boa source, I'll 
> generate a hardware description...  it's called a microprocessor 
> operating on stored opcodes, with a memory subsystem, and ...  :-)
>
> What is hardware?  What is software?  Are they really distinguishable? 
> Does it matter?
>
> John
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