Re: [microblaze-uclinux] OT?, Performance

[emanuel stiebler <emu@xxxxxxxxxxx>]

Goran Bilski wrote:

> A VAX 780 could do 1757 iterations/s.

It is also called dhrystones per second

> This is what is called 1 DMIPS.

Or VAX MIPS

>  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.

Slow memory ? I thought the MB vanilla has DDRAM ?
And still, around 30 times slower than on the xilinx web ?

> 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.

Sorry, Göran, but you didn't notice, that this was for the VirtexIIPro,
not for the MicroBlaze. And as the 2VP7 runs at 100 MHz, the expectation
would be around 150 DMIPS, as the VirtexIIPro has 32 KByte cache already
(16K icache, 16k dcache)

So, in both cases we have a pretty impressive difference to the
web numbers (but we still don't have a value for the MicroBlaze with 
caches on)

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

So at least the VirtexIIPro chips should reach it, but they don't :(

Cheers,
emanuel

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