Difference between revisions of "MASC/Elastic System"
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This tutorial is to demonstrate how to create an Elastic System design using the default MASC synthesis flow. | This tutorial is to demonstrate how to create an Elastic System design using the default MASC synthesis flow. | ||
| − | The first you need, if you're not yet, is to familiarize with the concept of Elastic System, the following papers should give a good introduction to the topic [ | + | The first you need, if you're not yet, is to familiarize with the concept of Elastic System, the following papers should give a good introduction to the topic [http://www.cs.upc.edu/~jordicf/gavina/BIB/files/self_tau06.pdf SELF], [http://dspace.mit.edu/handle/1721.1/58834 LI_BDN] and [http://www.cs.columbia.edu/~luca/research/lipTransactions.pdf LIDs]. |
| − | Once you know enough about the concept of Elastic Systems, you need to get access to the RTL repo of the MASC lab (mascrtl), check instructions [GIT_Repository | + | |
| + | There is one important difference between the approaches in these papers and the approach we use in the lab. The previous approaches have an automated flow that convert regular synchronous RTL code into elastic systems. This leads to some limitations in the types of transformations that are possible in the circuits. In the approach adopted at MASC, we require the designer to explicit write RTL using the elastic syntax. For that, we provide a custom implementation of the elastic buffer, that must be declared in the RTL code. Also, the handshake signals have to be generated by the designer. | ||
| + | |||
| + | Once you know enough about the concept of Elastic Systems, you need to get access to the RTL repo of the MASC lab (mascrtl), check instructions [[GIT_Repository]]. In the remainder of this tutorial, <mascrtl> will indicate directory to which the repository was checked-out. Thus, <mascrtl>/code indicates the directory code inside the mascrtl repository, and so forth. | ||
| + | |||
| + | == Glossary == | ||
A couple of remarks that may be useful for mapping the contents of the papers into the vocabulary used here. | A couple of remarks that may be useful for mapping the contents of the papers into the vocabulary used here. | ||
| − | |||
| − | |||
| − | + | * '''Elastic Systems''', '''Latency Insensitive''' and '''Synchronous with Handshakes''': different names used in the literature, indicate the same thing (or almost the same thing). | |
| + | * '''Valid''' and '''Stop''' signals are the handshakes signals used in the papers. LI-BDNs uses queue operations intead ('''enqueue''', '''dequeue''', '''empty''' and '''full'''. Although our papers also use valid/stop, in our verilog the names used are '''valid''' and '''retry'''. | ||
| + | * '''Elastic buffers''' are called '''stages''' in our verilog, but are essentially the same thing. | ||
| + | |||
| + | |||
| + | |||
| + | == Methodology == | ||
| + | |||
| + | The tutorial starts by presenting a simple circuit, to get the reader familiarized with the flow and the behavior and testing of elastic. We will call this circuit "Hello, Elastic". It consists of a simple buffer that returns '0' if the input is odd, and returns the input divided by two if it is even. | ||
| + | A testbench will also be generated to verify the functionality. | ||
| + | Then, we are going to create an elastic multiplier, with the relevant testbench. The topology used for the multiplier is the so-called shift-adder, which takes an arbitrary number of cycles to complete. | ||
| + | |||
| + | |||
| + | |||
| + | == Hello Elastic == | ||
| + | |||
| + | === Creating an RTL project === | ||
| + | |||
| + | Start by creating a new project, named 'hello' as described in [[Synthesis Setup]]. | ||
| + | |||
| + | |||
| + | == Multiplier == | ||
| − | + | (Explain arithmetically how the multiplier works). | |
Revision as of 18:29, 10 June 2015
Contents
Elastic System Tutorial
This tutorial is to demonstrate how to create an Elastic System design using the default MASC synthesis flow. The first you need, if you're not yet, is to familiarize with the concept of Elastic System, the following papers should give a good introduction to the topic SELF, LI_BDN and LIDs.
There is one important difference between the approaches in these papers and the approach we use in the lab. The previous approaches have an automated flow that convert regular synchronous RTL code into elastic systems. This leads to some limitations in the types of transformations that are possible in the circuits. In the approach adopted at MASC, we require the designer to explicit write RTL using the elastic syntax. For that, we provide a custom implementation of the elastic buffer, that must be declared in the RTL code. Also, the handshake signals have to be generated by the designer.
Once you know enough about the concept of Elastic Systems, you need to get access to the RTL repo of the MASC lab (mascrtl), check instructions GIT_Repository. In the remainder of this tutorial, <mascrtl> will indicate directory to which the repository was checked-out. Thus, <mascrtl>/code indicates the directory code inside the mascrtl repository, and so forth.
Glossary
A couple of remarks that may be useful for mapping the contents of the papers into the vocabulary used here.
- Elastic Systems, Latency Insensitive and Synchronous with Handshakes: different names used in the literature, indicate the same thing (or almost the same thing).
- Valid and Stop signals are the handshakes signals used in the papers. LI-BDNs uses queue operations intead (enqueue, dequeue, empty and full. Although our papers also use valid/stop, in our verilog the names used are valid and retry.
- Elastic buffers are called stages in our verilog, but are essentially the same thing.
Methodology
The tutorial starts by presenting a simple circuit, to get the reader familiarized with the flow and the behavior and testing of elastic. We will call this circuit "Hello, Elastic". It consists of a simple buffer that returns '0' if the input is odd, and returns the input divided by two if it is even. A testbench will also be generated to verify the functionality. Then, we are going to create an elastic multiplier, with the relevant testbench. The topology used for the multiplier is the so-called shift-adder, which takes an arbitrary number of cycles to complete.
Hello Elastic
Creating an RTL project
Start by creating a new project, named 'hello' as described in Synthesis Setup.
Multiplier
(Explain arithmetically how the multiplier works).
