Answer: maximum number of state machines in a current chip: > 500k

[Weng Tianxiang]

Hi,
Here is the answer to the maximum number of state machines in a
current chip: > 500k.

My original answer posing has some errors.

1. It is L2 cache that uses a lot of state machines;
http://en.wikipedia.org/wiki/Cache_coherence

2. IBM/Intel uses MESI protocol (4 states: Modified, Exclusive, Shared
and
Invalid);
http://en.wikipedia.org/wiki/MESI_protocol


3. Please visit Intel product website to get the latest http://download.intel.com/products/processor/xeon/7300_prodbrief.pdf


4. "with up to 8 MB of L2 cache per processor" and 4 processors.
It means 4*8MB = 32MB L2 cache;

5. L2 cache is divided into data L2 cache and instruction L2 cache and
only data L2 cache uses MESI protocol.

6. Each 32Bytes is a cache line;

7. 32MB/2/32 = 500k cache lines in data L2 cache and 500k state
machines using MESI protocol.

8. L1/L3 cache and instruction L2 cache use several independent 1-bit
flip-flops to recode their states so that they are not counted as
state machines.

The final answer is:
There is at least 500k state machines in Intel chip.

a. It is available to every users in the topics groups;
b. They are written in Verilog, not in VHDL;
c. FPGA has never had a design using L2 cache.

Weng

 

[Jonathan Bromley]

The final answer is:
There is at least 500k state machines in Intel chip.

a. It is available to every users in the topics groups;

Likewise, the mediaeval discussions about how many angels
can dance on the head of a pin are accessible to all.
In both cases, most of us don't care.

b. They are written in Verilog, not in VHDL;

Utterly unimportant, and possibly not even true.
Intel uses a range of proprietary in-house tools
and languages in addition to Verilog.

c. FPGA has never had a design using L2 cache.

Even if that is true, I defy you to prove it.
--
Jonathan Bromley, Consultant

DOULOS - Developing Design Know-how
VHDL * Verilog * SystemC * e * Perl * Tcl/Tk * Project Services

Doulos Ltd., 22 Market Place, Ringwood, BH24 1AW, UK
(e-mail address removed)
http://www.MYCOMPANY.com

The contents of this message may contain personal views which
are not the views of Doulos Ltd., unless specifically stated.

 

[John Retta]

Which leads us to another interesting question ....

What are the maximium number of lemons that
the human mind can imagine being rotated
simultaneously?

[Please note the lemons can not be bruised.
This is a degenerate case that the theorem does
not apply]

--
Regards,
John Retta
Owner and Designer
Retta Technical Consulting Inc.

email : (e-mail address removed)
web : www.rtc-inc.com

 

[Evan Lavelle]

At last - something interesting in this thread.


Why? Wouldn't the smart thing be to build *one* cache coherency
controller in your chip, and to save your 2 state bits as two extra
bits in the 256 memory bits in your cache block?

Likewise, the mediaeval discussions about how many angels
can dance on the head of a pin are accessible to all.
In both cases, most of us don't care.

Actually, to the religiously inclined (among whose number I am not,
alas, to be counted) this is potentially a very interesting question.
The debate was actually about whether or not Angels had a corporeal
existence; the title was just whimsy. Thomas Aquinas's answer, for the
case of a pinhead which was a geometrical point, was, I think, 'one'.

So, maybe there was something fundamental we missed in the original
question. Was it just an allegory? One FSM, one Angel. Spooky.

 

[neilla]

Hi,
Here is the answer to the maximum number of state machines in a
current chip: > 500k.

My original answer posing has some errors.

And there is also one more big error.

3. Please visit Intel product website to get the latest news:http://download.intel.com/products/processor/xeon/7300_prodbrief.pdf

4. "with up to 8 MB of L2 cache per processor" and 4 processors.
It means 4*8MB = 32MB L2 cache;

If you read the product brief again, you should see that there is only
8MB of L2 on the whole chip. This is split into 2 sets of 4MB which
can then be accessed by 2 cores. Where Intel says processor they are
referring to the whole chip, and core is used to refer to the 4
processors on the chip.

 

[Mike Lewis]

Hi,
Here is the answer to the maximum number of state machines in a
current chip: > 500k.

My original answer posing has some errors.

1. It is L2 cache that uses a lot of state machines;
http://en.wikipedia.org/wiki/Cache_coherence

2. IBM/Intel uses MESI protocol (4 states: Modified, Exclusive, Shared
and
Invalid);
http://en.wikipedia.org/wiki/MESI_protocol


3. Please visit Intel product website to get the latest http://download.intel.com/products/processor/xeon/7300_prodbrief.pdf


4. "with up to 8 MB of L2 cache per processor" and 4 processors.
It means 4*8MB = 32MB L2 cache;

5. L2 cache is divided into data L2 cache and instruction L2 cache and
only data L2 cache uses MESI protocol.

6. Each 32Bytes is a cache line;

7. 32MB/2/32 = 500k cache lines in data L2 cache and 500k state
machines using MESI protocol.

8. L1/L3 cache and instruction L2 cache use several independent 1-bit
flip-flops to recode their states so that they are not counted as
state machines.

The final answer is:
There is at least 500k state machines in Intel chip.

a. It is available to every users in the topics groups;
b. They are written in Verilog, not in VHDL;
c. FPGA has never had a design using L2 cache.

Weng

saying that there are more than 500K state machines has not stated what the
maximum number can be.

 

[ghelbig]

Hi,
Here is the answer to the maximum number of state machines in a
current chip: > 500k.

My original answer posing has some errors.

It all depends on how you look at it; from a certain point of view,
the correct answer is one (1).

What you are calling state machines are just subordinate pieces of one
grand state machine.

G.