AMD FX-8150 Bulldozer finally tested

[Drwho?]

No, the front is vertical multi threaded, i.e. every clock 4 decoders to one thread, in the next clock to the other. If the 2nd thread does not decode anything, obviously the other thread can have the front end longer than 1 clock cycle ;-)
bulldozer4b.jpg


How do you count to 5 now? Do you include the Macro Op Fusion, too? There are only 3fastpath plus 1 complex decoder in Intel's design. Officially they count 4:
32_m.png
Anyways, MacroOpFusion is used with Bulldozer, too now, so you have to count 5 for AMD, too (however in less cases, AMD's fusion is on the Conroe's level, Nehalem got more fusion capabilities, not sure about Sandy now.)


As said above, each thread has 4 or if you count Fusion then 5 decoders. How is intel running Hyperthreading on the 3+1 decoders? Each thread gets 4 decoders, so 8 total? That would be new to me and intel. If intel does it in another way than AMD, then they have to run both threads simultaneously. However, that would mean "only" 2 decoders for each thread, and that's exactly the baaaad case you wrote about above in your incorrect statement about AMD's decoder in the beginning.


Discussion is always fine, however in the above case, I assume you are rather wrong.

cheers

Opteron

I propose you take a simple linear algorithm and run it on one thread, then, count the number of instructions retired, and then, divide by the number of clock ticks ... You ll be surprise ;-)
( make sure your code is totally compute, with 1 to 2 instructions dependancy ... )

Power point are one thing, but measuring and checking yourself is much better ... Otherwise , at 4.2ghz, how could you explain the poor performance of BD on superPI? Low IPC ... Then, ask yourself, if you measure the IPC for each thread, why it never goes about 2 on a single thread ... Please experiment before trying to correct me. I did my homework ;-)


Then , for your intel diagram, you forgot to count code fusion ... SandyB is 4 large + Fusion ... That gives you up to 5!

We saw a lot of powerpoint slide, but the measurement don t match what is showed in the ppt, sorry, you assume the marketing slide are correct, this is where is the gap. I looked for everywhere, I could not find anywhere clearly said that it will decode more than 2 per threads, and match it with an ASM code doing more than 2 IPC , did you try?


Hehe ...

Francois