_site/example_configs/index.html - public/gem5-website - Git at Google

 <!DOCTYPE html>
 <html>
 <head>
 	<meta charset="utf-8">
 	<meta http-equiv="x-ua-compatible" content="ie=edge">
 	<meta name="viewport" content="width=device-width, initial-scale=1">

 	<title>gem5</title>

 	<!-- SITE FAVICON -->
 	<link rel="shortcut icon" type="image/gif" href="/assets/img/gem5ColorVert.gif"/>

 	<link rel="canonical" href="http://localhost:4000/example_configs/">
 	<link href='https://fonts.googleapis.com/css?family=Open+Sans:400,300,700,800,600' rel='stylesheet' type='text/css'>
 	<link href='https://fonts.googleapis.com/css?family=Muli:400,300' rel='stylesheet' type='text/css'>

 	<!-- FAVICON -->
 	<link rel="stylesheet" href="//maxcdn.bootstrapcdn.com/font-awesome/4.3.0/css/font-awesome.min.css">

 	<!-- BOOTSTRAP -->
 	<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/css/bootstrap.min.css" integrity="sha384-MCw98/SFnGE8fJT3GXwEOngsV7Zt27NXFoaoApmYm81iuXoPkFOJwJ8ERdknLPMO" crossorigin="anonymous">

 	<!-- CUSTOM CSS -->
 	<link rel="stylesheet" href="/css/main.css">
 </head>


 <body>
 	<nav class="navbar navbar-expand-md navbar-light bg-light">
   <a class="navbar-brand" href="/">
 		<img src="/assets/img/gem5ColorLong.gif" alt="gem5" height=45px>
 	</a>
   <button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarNavDropdown" aria-controls="navbarNavDropdown" aria-expanded="false" aria-label="Toggle navigation">
     <span class="navbar-toggler-icon"></span>
   </button>
   <div class="collapse navbar-collapse" id="navbarNavDropdown">
     <ul class="navbar-nav ml-auto">
       <li class="nav-item ">
         <a class="nav-link" href="/">Home</a>
       </li>

 			<li class="nav-item dropdown ">
 				<a class="nav-link dropdown-toggle" href="/about" id="navbarDropdownMenuLink" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
 					About
 				</a>
 				<div class="dropdown-menu" aria-labelledby="navbarDropdownMenuLink">
           <a class="dropdown-item" href="/about">About</a>
           <a class="dropdown-item" href="/publications">Publications</a>
           <a class="dropdown-item" href="/governance">Governance</a>
 				</div>
 			</li>

 			<li class="nav-item dropdown active">
 				<a class="nav-link dropdown-toggle" href="#" id="navbarDropdownMenuLink" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
 					Documentation
 				</a>
 				<div class="dropdown-menu" aria-labelledby="navbarDropdownMenuLink">
 					<!-- Pull navigation from _data/documentation.yml -->

             <a class="dropdown-item" href="/introduction">Introduction</a>

             <a class="dropdown-item" href="/building">Getting Started</a>

             <a class="dropdown-item" href="/environment">Modifying/Extending</a>

             <a class="dropdown-item" href="/MSIintro">Modeling Cache Coherence with Ruby</a>

 				</div>
 			</li>

       <li class="nav-item ">
         <a class="nav-link" href="/contributing">Contributing</a>
       </li>

 			<li class="nav-item ">
         <a class="nav-link" href="/search">Search</a>
       </li>
     </ul>
   </div>
 </nav>

 	<main>
 		<div class="sidenav-top">
   <img src="/assets/img/gem5ColorLong.gif" height="80">
   <div class="search">
     <form action="/search" method="get">
       <!-- <label for="search-box"><i class="fa fa-search"></i></label> -->
       <input type="text" name="query">
       <button type="submit" name="submit"><i class="fa fa-search"></i></button>
     </form>
   </div>
 </div>
 <div class="sidenav">
   <!-- Pull navigation from _data/documentation.yml -->

     <a class="item" href="/introduction" role="button" aria-expanded="false" aria-controls="collapseExample">
       Introduction
     </a>
     <div class="collapse " id="introdution">

     </div>

     <a class="item" data-toggle="collapse" href="#pt1" role="button" aria-expanded="false" aria-controls="collapseExample">
       Getting Started
     </a>
     <div class="collapse show" id="pt1">

         <a class="subitem " href="/building">Building gem5</a>

         <a class="subitem " href="/simple_config">Creating a simple configuration script</a>

         <a class="subitem " href="/cache_config">Adding cache to configuration script</a>

         <a class="subitem " href="/gem5_stats">Understanding gem5 statistics and output</a>

         <a class="subitem active" href="/example_configs">Using the default configuration scripts</a>

     </div>

     <a class="item" data-toggle="collapse" href="#pt2" role="button" aria-expanded="false" aria-controls="collapseExample">
       Modifying/Extending
     </a>
     <div class="collapse " id="pt2">

         <a class="subitem " href="/environment">Setting up your development environment</a>

         <a class="subitem " href="/helloobject">Creating a very simple SimObject</a>

         <a class="subitem " href="/debugging">Debugging gem5</a>

         <a class="subitem " href="/events">Event-driven programming</a>

         <a class="subitem " href="/parameters">Adding parameters to SimObjects and more events</a>

         <a class="subitem " href="/memoryobject">Creating SimObjects in the memory system</a>

         <a class="subitem " href="/simplecache">Creating a simple cache object</a>

     </div>

     <a class="item" data-toggle="collapse" href="#pt3" role="button" aria-expanded="false" aria-controls="collapseExample">
       Modeling Cache Coherence with Ruby
     </a>
     <div class="collapse " id="pt3">

         <a class="subitem " href="/MSIintro">Introduction to Ruby</a>

         <a class="subitem " href="/cache-intro">MSI example cache protocol</a>

         <a class="subitem " href="/cache-declarations">Declaring a state machine</a>

         <a class="subitem " href="/cache-in-ports">In port code blocks</a>

         <a class="subitem " href="/cache-actions">Action code blocks</a>

         <a class="subitem " href="/cache-transitions">Transition code blocks</a>

         <a class="subitem " href="/directory">MSI Directory implementation</a>

         <a class="subitem " href="/MSIbuilding">Compiling a SLICC protocol</a>

         <a class="subitem " href="/configuration">Configuring a simple Ruby system</a>

         <a class="subitem " href="/running">Running the simple Ruby system</a>

         <a class="subitem " href="/MSIdebugging">Debugging SLICC Protocols</a>

         <a class="subitem " href="/simple-MI_example">Configuring for a standard protocol</a>

     </div>

 </div>

 <div class="container" id="doc-container">

   <!-- <h1>Using the default configuration scripts</h1> -->
   <dl>
   <dt>authors</dt>
   <dd>Jason Lowe-Power</dd>
 </dl>

 <h1 id="using-the-default-configuration-scripts">Using the default configuration scripts</h1>

 <p>In this chapter, we’ll explore using the default configuration scripts
 that come with gem5. gem5 ships with many configuration scripts that
 allow you to use gem5 very quickly. However, a common pitfall is to use
 these scripts without fully understanding what is being simulated. It is
 important when doing computer architecture research with gem5 to fully
 understand the system you are simulating. This chapter will walk you
 through some important options and parts of the default configuration
 scripts.</p>

 <p>In the last few chapters you have created your own configuration scripts
 from scratch. This is very powerful, as it allows you to specify every
 single system parameter. However, some systems are very complex to set
 up (e.g., a full-system ARM or x86 machine). Luckily, the gem5
 developers have provided many scripts to bootstrap the process of
 building systems.</p>

 <h2 id="a-tour-of-the-directory-structure">A tour of the directory structure</h2>

 <p>All of gem5’s configuration files can be found in <code class="highlighter-rouge">configs/</code>. The
 directory structure is shown below:</p>

 <div class="highlighter-rouge"><div class="highlight"><pre class="highlight"><code>configs/boot:
 ammp.rcS            halt.sh                micro_tlblat2.rcS              netperf-stream-udp-local.rcS
 ...

 configs/common:
 Benchmarks.py     cpu2000.py     Options.py
 Caches.py         FSConfig.py    O3_ARM_v7a.py     SysPaths.py
 CacheConfig.py    CpuConfig.py   MemConfig.py      Simulation.py

 configs/dram:
 sweep.py

 configs/example:
 fs.py       read_config.py       ruby_mem_test.py      ruby_random_test.py
 memtest.py  ruby_direct_test.py  ruby_network_test.py  se.py

 configs/ruby:
 MESI_Three_Level.py  MI_example.py           MOESI_CMP_token.py  Network_test.py
 MESI_Two_Level.py    MOESI_CMP_directory.py  MOESI_hammer.py     Ruby.py

 configs/splash2:
 cluster.py  run.py

 configs/topologies:
 BaseTopology.py  Cluster.py  Crossbar.py  MeshDirCorners.py  Mesh.py  Pt2Pt.py  Torus.py
 </code></pre></div></div>

 <p>Each directory is briefly described below:</p>

 <dl>
   <dt><strong>boot/</strong></dt>
   <dd>These are rcS files which are used in full-system mode. These files
 are loaded by the simulator after Linux boots and are executed by
 the shell. Most of these are used to control benchmarks when running
 in full-system mode. Some are utility functions, like
 <code class="highlighter-rouge">hack_back_ckpt.rcS</code>. These files are covered in more depth in the
 chapter on full-system simulation.</dd>
   <dt><strong>common/</strong></dt>
   <dd>This directory contains a number of helper scripts and functions to
 create simulated systems. For instance, <code class="highlighter-rouge">Caches.py</code> is similar to
 the <code class="highlighter-rouge">caches.py</code> and <code class="highlighter-rouge">caches_opts.py</code> files created in previous
 chapters.

     <p><code class="highlighter-rouge">Options.py</code> contains a variety of options that can be set on the
 command line. Like the number of CPUs, system clock, and many, many
 more. This is a good place to look to see if the option you want to
 change already has a command line parameter.</p>

     <p><code class="highlighter-rouge">CacheConfig.py</code> contains the options and functions for setting
 cache parameters for the classic memory system.</p>

     <p><code class="highlighter-rouge">MemConfig.py</code> provides some helper functions for setting the memory
 system.</p>

     <p><code class="highlighter-rouge">FSConfig.py</code> contains the necessary functions to set up full-system
 simulation for many different kinds of systems. Full-system
 simulation is discussed further in it’s own chapter.</p>

     <p><code class="highlighter-rouge">Simulation.py</code> contains many helper functions to set up and run
 gem5. A lot of the code contained in this file manages saving and
 restoring checkpoints. The example configuration files below in
 <code class="highlighter-rouge">examples/</code> use the functions in this file to execute the gem5
 simulation. This file is quite complicated, but it also allows a lot
 of flexibility in how the simulation is run.</p>
   </dd>
   <dt><strong>dram/</strong></dt>
   <dd>Contains scripts to test DRAM.</dd>
   <dt><strong>example/</strong></dt>
   <dd>This directory contains some example gem5 configuration scripts that
 can be used out-of-the-box to run gem5. Specifically, <code class="highlighter-rouge">se.py</code> and
 <code class="highlighter-rouge">fs.py</code> are quite useful. More on these files can be found in the
 next section. There are also some other utility configuration
 scripts in this directory.</dd>
   <dt><strong>ruby/</strong></dt>
   <dd>This directory contains the configurations scripts for Ruby and its
 included cache coherence protocols. More details can be found in the
 chapter on Ruby.</dd>
   <dt><strong>splash2/</strong></dt>
   <dd>This directory contains scripts to run the splash2 benchmark suite
 with a few options to configure the simulated system.</dd>
   <dt><strong>topologies/</strong></dt>
   <dd>This directory contains the implementation of the topologies that
 can be used when creating the Ruby cache hierarchy. More details can
 be found in the chapter on Ruby.</dd>
 </dl>

 <h2 id="using-sepy-and-fspy">Using <code class="highlighter-rouge">se.py</code> and <code class="highlighter-rouge">fs.py</code></h2>

 <p>In this section, I’ll discuss some of the common options that can be
 passed on the command line to <code class="highlighter-rouge">se.py</code> and <code class="highlighter-rouge">fs.py</code>. More details on how
 to run full-system simulation can be found in the full-system simulation
 chapter. Here I’ll discuss the options that are common to the two files.</p>

 <p>Most of the options discussed in this section are found in Options.py
 and are registered in the function <code class="highlighter-rouge">addCommonOptions</code>. This section does
 not detail all of the options. To see all of the options, run the
 configuration script with <code class="highlighter-rouge">--help</code>, or read the script’s source code.</p>

 <p>First, let’s simply run the hello world program without any parameters:</p>

 <p>``` {.sourceCode .sh}
 build/X86/gem5.opt configs/example/se.py –cmd=tests/test-progs/hello/bin/x86/linux/hello</p>
 <div class="highlighter-rouge"><div class="highlight"><pre class="highlight"><code>
 And we get the following as output:

     gem5 Simulator System.  http://gem5.org
     gem5 is copyrighted software; use the --copyright option for details.

     gem5 compiled Jan 14 2015 16:11:34
     gem5 started Feb  2 2015 15:22:24
     gem5 executing on mustardseed.cs.wisc.edu
     command line: build/X86/gem5.opt configs/example/se.py --cmd=tests/test-progs/hello/bin/x86/linux/hello
     Global frequency set at 1000000000000 ticks per second
     warn: DRAM device capacity (8192 Mbytes) does not match the address range assigned (512 Mbytes)
     0: system.remote_gdb.listener: listening for remote gdb #0 on port 7000
     **** REAL SIMULATION ****
     info: Entering event queue @ 0.  Starting simulation...
     Hello world!
     Exiting @ tick 5942000 because target called exit()

 However, this isn't a very interesting simulation at all! By default,
 gem5 uses the atomic CPU and uses atomic memory accesses, so there's no
 real timing data reported! To confirm this, you can look at
 m5out/config.ini. The CPU is shown on line 46:

     [system.cpu]
     type=AtomicSimpleCPU
     children=apic_clk_domain dtb interrupts isa itb tracer workload
     branchPred=Null
     checker=Null
     clk_domain=system.cpu_clk_domain
     cpu_id=0
     do_checkpoint_insts=true
     do_quiesce=true
     do_statistics_insts=true

 To actually run gem5 in timing mode, let's specify a CPU type. While
 we're at it, we can also specify sizes for the L1 caches.

 ``` {.sourceCode .sh}
 build/X86/gem5.opt configs/example/se.py --cmd=tests/test-progs/hello/bin/x86/linux/hello --cpu-type=TimingSimpleCPU --l1d_size=64kB --l1i_size=16kB
 </code></pre></div></div>

 <div class="highlighter-rouge"><div class="highlight"><pre class="highlight"><code>gem5 Simulator System.  http://gem5.org
 gem5 is copyrighted software; use the --copyright option for details.

 gem5 compiled Jan 14 2015 16:11:34
 gem5 started Feb  2 2015 15:26:57
 gem5 executing on mustardseed.cs.wisc.edu
 command line: build/X86/gem5.opt configs/example/se.py --cmd=tests/test-progs/hello/bin/x86/linux/hello --cpu-type=TimingSimpleCPU --l1d_size=64kB --l1i_size=16kB
 Global frequency set at 1000000000000 ticks per second
 warn: DRAM device capacity (8192 Mbytes) does not match the address range assigned (512 Mbytes)
 0: system.remote_gdb.listener: listening for remote gdb #0 on port 7000
 **** REAL SIMULATION ****
 info: Entering event queue @ 0.  Starting simulation...
 Hello world!
 Exiting @ tick 344986500 because target called exit()
 </code></pre></div></div>

 <p>Now, let’s check the config.ini file and make sure that these options
 propagated correctly to the final system. If you search
 <code class="highlighter-rouge">m5out/config.ini</code> for “cache”, you’ll find that no caches were created!
 Even though we specified the size of the caches, we didn’t specify that
 the system should use caches, so they weren’t created. The correct
 command line should be:</p>

 <p>``` {.sourceCode .sh}
 build/X86/gem5.opt configs/example/se.py –cmd=tests/test-progs/hello/bin/x86/linux/hello –cpu-type=TimingSimpleCPU –l1d_size=64kB –l1i_size=16kB –caches</p>
 <div class="highlighter-rouge"><div class="highlight"><pre class="highlight"><code>
     gem5 Simulator System.  http://gem5.org
     gem5 is copyrighted software; use the --copyright option for details.

     gem5 compiled Jan 14 2015 16:11:34
     gem5 started Feb  2 2015 15:29:20
     gem5 executing on mustardseed.cs.wisc.edu
     command line: build/X86/gem5.opt configs/example/se.py --cmd=tests/test-progs/hello/bin/x86/linux/hello --cpu-type=TimingSimpleCPU --l1d_size=64kB --l1i_size=16kB --caches
     Global frequency set at 1000000000000 ticks per second
     warn: DRAM device capacity (8192 Mbytes) does not match the address range assigned (512 Mbytes)
     0: system.remote_gdb.listener: listening for remote gdb #0 on port 7000
     **** REAL SIMULATION ****
     info: Entering event queue @ 0.  Starting simulation...
     Hello world!
     Exiting @ tick 29480500 because target called exit()

 On the last line, we see that the total time went from 344986500 ticks
 to 29480500, much faster! Looks like caches are probably enabled now.
 But, it's always a good idea to double check the `config.ini` file.

     [system.cpu.dcache]
     type=BaseCache
     children=tags
     addr_ranges=0:18446744073709551615
     assoc=2
     clk_domain=system.cpu_clk_domain
     demand_mshr_reserve=1
     eventq_index=0
     forward_snoops=true
     hit_latency=2
     is_top_level=true
     max_miss_count=0
     mshrs=4
     prefetch_on_access=false
     prefetcher=Null
     response_latency=2
     sequential_access=false
     size=65536
     system=system
     tags=system.cpu.dcache.tags
     tgts_per_mshr=20
     two_queue=false
     write_buffers=8
     cpu_side=system.cpu.dcache_port
     mem_side=system.membus.slave[2]

 Some common options `se.py` and `fs.py`
 ---------------------------------------

 All of the possible options are printed when you run:

 ``` {.sourceCode .sh}
 build/X86/gem5.opt configs/example/se.py --help
 </code></pre></div></div>

 <p>Below is a few important options from that list.</p>


 </div>

 	</main>

 	<script src="https://code.jquery.com/jquery-3.3.1.slim.min.js" integrity="sha384-q8i/X+965DzO0rT7abK41JStQIAqVgRVzpbzo5smXKp4YfRvH+8abtTE1Pi6jizo" crossorigin="anonymous"></script>
 	<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.3/umd/popper.min.js" integrity="sha384-ZMP7rVo3mIykV+2+9J3UJ46jBk0WLaUAdn689aCwoqbBJiSnjAK/l8WvCWPIPm49" crossorigin="anonymous"></script>
 	<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/js/bootstrap.min.js" integrity="sha384-ChfqqxuZUCnJSK3+MXmPNIyE6ZbWh2IMqE241rYiqJxyMiZ6OW/JmZQ5stwEULTy" crossorigin="anonymous"></script>

 	<script>
 	  // When the user scrolls down 20px from the top of the document, show the button
 	  window.onscroll = function() {scrollFunction()};

 	  function scrollFunction() {
 	      if (document.body.scrollTop > 100 || document.documentElement.scrollTop > 20) {
 	          document.getElementById("myBtn").style.display = "block";
 	      } else {
 	          document.getElementById("myBtn").style.display = "none";
 	      }
 	  }

 	  // When the user clicks on the button, scroll to the top of the document
 	  function topFunction() {
 	      document.body.scrollTop = 0;
 	      document.documentElement.scrollTop = 0;
 	  }
 	</script>

 </body>

 <footer class="page-footer">
 	<div class="container">
 		<div class="row">

 			<div class="col-12 col-sm-4">
 				<p><a href="/about">About</a></p>
 				<p><a href="/publications">Publications</a></p>
 				<p><a href="/contributing">Contributing</a></p>
 			</div><br>

 			<div class="col-12 col-sm-4">
 				<p><a href="/gettingstarted">Documentation</a></p>
 				<p><a href="#">Source</a></p>
 			</div><br>

 			<div class="col-12 col-sm-4">
 				<p><a href="/help">Help</a></p>
 				<p><a href="/search">Search</a></p>
 				<p><a href="#">Mailing Lists</a></p>
 			</div>

 		</div>
 	</div>
 </footer>


 </html>
	<!DOCTYPE html>
	<html>
	<head>
	<meta charset="utf-8">
	<meta http-equiv="x-ua-compatible" content="ie=edge">
	<meta name="viewport" content="width=device-width, initial-scale=1">

	<title>gem5</title>

	<!-- SITE FAVICON -->
	<link rel="shortcut icon" type="image/gif" href="/assets/img/gem5ColorVert.gif"/>

	<link rel="canonical" href="http://localhost:4000/example_configs/">
	<link href='https://fonts.googleapis.com/css?family=Open+Sans:400,300,700,800,600' rel='stylesheet' type='text/css'>
	<link href='https://fonts.googleapis.com/css?family=Muli:400,300' rel='stylesheet' type='text/css'>

	<!-- FAVICON -->
	<link rel="stylesheet" href="//maxcdn.bootstrapcdn.com/font-awesome/4.3.0/css/font-awesome.min.css">

	<!-- BOOTSTRAP -->
	<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/css/bootstrap.min.css" integrity="sha384-MCw98/SFnGE8fJT3GXwEOngsV7Zt27NXFoaoApmYm81iuXoPkFOJwJ8ERdknLPMO" crossorigin="anonymous">

	<!-- CUSTOM CSS -->
	<link rel="stylesheet" href="/css/main.css">
	</head>


	<body>
	<nav class="navbar navbar-expand-md navbar-light bg-light">
	<a class="navbar-brand" href="/">
	<img src="/assets/img/gem5ColorLong.gif" alt="gem5" height=45px>
	</a>
	<button class="navbar-toggler" type="button" data-toggle="collapse" data-target="#navbarNavDropdown" aria-controls="navbarNavDropdown" aria-expanded="false" aria-label="Toggle navigation">
	<span class="navbar-toggler-icon"></span>
	</button>
	<div class="collapse navbar-collapse" id="navbarNavDropdown">
	<ul class="navbar-nav ml-auto">
	<li class="nav-item ">
	<a class="nav-link" href="/">Home</a>
	</li>

	<li class="nav-item dropdown ">
	<a class="nav-link dropdown-toggle" href="/about" id="navbarDropdownMenuLink" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
	About
	</a>
	<div class="dropdown-menu" aria-labelledby="navbarDropdownMenuLink">
	<a class="dropdown-item" href="/about">About</a>
	<a class="dropdown-item" href="/publications">Publications</a>
	<a class="dropdown-item" href="/governance">Governance</a>
	</div>
	</li>

	<li class="nav-item dropdown active">
	<a class="nav-link dropdown-toggle" href="#" id="navbarDropdownMenuLink" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
	Documentation
	</a>
	<div class="dropdown-menu" aria-labelledby="navbarDropdownMenuLink">
	<!-- Pull navigation from _data/documentation.yml -->

	<a class="dropdown-item" href="/introduction">Introduction</a>

	<a class="dropdown-item" href="/building">Getting Started</a>

	<a class="dropdown-item" href="/environment">Modifying/Extending</a>

	<a class="dropdown-item" href="/MSIintro">Modeling Cache Coherence with Ruby</a>

	</div>
	</li>

	<li class="nav-item ">
	<a class="nav-link" href="/contributing">Contributing</a>
	</li>

	<li class="nav-item ">
	<a class="nav-link" href="/search">Search</a>
	</li>
	</ul>
	</div>
	</nav>

	<main>
	<div class="sidenav-top">
	<img src="/assets/img/gem5ColorLong.gif" height="80">
	<div class="search">
	<form action="/search" method="get">
	<!-- <label for="search-box"><i class="fa fa-search"></i></label> -->
	<input type="text" name="query">
	<button type="submit" name="submit"><i class="fa fa-search"></i></button>
	</form>
	</div>
	</div>
	<div class="sidenav">
	<!-- Pull navigation from _data/documentation.yml -->

	<a class="item" href="/introduction" role="button" aria-expanded="false" aria-controls="collapseExample">
	Introduction
	</a>
	<div class="collapse " id="introdution">

	</div>

	<a class="item" data-toggle="collapse" href="#pt1" role="button" aria-expanded="false" aria-controls="collapseExample">
	Getting Started
	</a>
	<div class="collapse show" id="pt1">

	<a class="subitem " href="/building">Building gem5</a>

	<a class="subitem " href="/simple_config">Creating a simple configuration script</a>

	<a class="subitem " href="/cache_config">Adding cache to configuration script</a>

	<a class="subitem " href="/gem5_stats">Understanding gem5 statistics and output</a>

	<a class="subitem active" href="/example_configs">Using the default configuration scripts</a>

	</div>

	<a class="item" data-toggle="collapse" href="#pt2" role="button" aria-expanded="false" aria-controls="collapseExample">
	Modifying/Extending
	</a>
	<div class="collapse " id="pt2">

	<a class="subitem " href="/environment">Setting up your development environment</a>

	<a class="subitem " href="/helloobject">Creating a very simple SimObject</a>

	<a class="subitem " href="/debugging">Debugging gem5</a>

	<a class="subitem " href="/events">Event-driven programming</a>

	<a class="subitem " href="/parameters">Adding parameters to SimObjects and more events</a>

	<a class="subitem " href="/memoryobject">Creating SimObjects in the memory system</a>

	<a class="subitem " href="/simplecache">Creating a simple cache object</a>

	</div>

	<a class="item" data-toggle="collapse" href="#pt3" role="button" aria-expanded="false" aria-controls="collapseExample">
	Modeling Cache Coherence with Ruby
	</a>
	<div class="collapse " id="pt3">

	<a class="subitem " href="/MSIintro">Introduction to Ruby</a>

	<a class="subitem " href="/cache-intro">MSI example cache protocol</a>

	<a class="subitem " href="/cache-declarations">Declaring a state machine</a>

	<a class="subitem " href="/cache-in-ports">In port code blocks</a>

	<a class="subitem " href="/cache-actions">Action code blocks</a>

	<a class="subitem " href="/cache-transitions">Transition code blocks</a>

	<a class="subitem " href="/directory">MSI Directory implementation</a>

	<a class="subitem " href="/MSIbuilding">Compiling a SLICC protocol</a>

	<a class="subitem " href="/configuration">Configuring a simple Ruby system</a>

	<a class="subitem " href="/running">Running the simple Ruby system</a>

	<a class="subitem " href="/MSIdebugging">Debugging SLICC Protocols</a>

	<a class="subitem " href="/simple-MI_example">Configuring for a standard protocol</a>

	</div>

	</div>

	<div class="container" id="doc-container">

	<!-- <h1>Using the default configuration scripts</h1> -->
	<dl>
	<dt>authors</dt>
	<dd>Jason Lowe-Power</dd>
	</dl>

	<h1 id="using-the-default-configuration-scripts">Using the default configuration scripts</h1>

	<p>In this chapter, we’ll explore using the default configuration scripts
	that come with gem5. gem5 ships with many configuration scripts that
	allow you to use gem5 very quickly. However, a common pitfall is to use
	these scripts without fully understanding what is being simulated. It is
	important when doing computer architecture research with gem5 to fully
	understand the system you are simulating. This chapter will walk you
	through some important options and parts of the default configuration
	scripts.</p>

	<p>In the last few chapters you have created your own configuration scripts
	from scratch. This is very powerful, as it allows you to specify every
	single system parameter. However, some systems are very complex to set
	up (e.g., a full-system ARM or x86 machine). Luckily, the gem5
	developers have provided many scripts to bootstrap the process of
	building systems.</p>

	<h2 id="a-tour-of-the-directory-structure">A tour of the directory structure</h2>

	<p>All of gem5’s configuration files can be found in <code class="highlighter-rouge">configs/</code>. The
	directory structure is shown below:</p>

	<div class="highlighter-rouge"><div class="highlight"><pre class="highlight"><code>configs/boot:
	ammp.rcS halt.sh micro_tlblat2.rcS netperf-stream-udp-local.rcS
	...

	configs/common:
	Benchmarks.py cpu2000.py Options.py
	Caches.py FSConfig.py O3_ARM_v7a.py SysPaths.py
	CacheConfig.py CpuConfig.py MemConfig.py Simulation.py

	configs/dram:
	sweep.py

	configs/example:
	fs.py read_config.py ruby_mem_test.py ruby_random_test.py
	memtest.py ruby_direct_test.py ruby_network_test.py se.py

	configs/ruby:
	MESI_Three_Level.py MI_example.py MOESI_CMP_token.py Network_test.py
	MESI_Two_Level.py MOESI_CMP_directory.py MOESI_hammer.py Ruby.py

	configs/splash2:
	cluster.py run.py

	configs/topologies:
	BaseTopology.py Cluster.py Crossbar.py MeshDirCorners.py Mesh.py Pt2Pt.py Torus.py
	</code></pre></div></div>

	<p>Each directory is briefly described below:</p>

	<dl>
	<dt><strong>boot/</strong></dt>
	<dd>These are rcS files which are used in full-system mode. These files
	are loaded by the simulator after Linux boots and are executed by
	the shell. Most of these are used to control benchmarks when running
	in full-system mode. Some are utility functions, like
	<code class="highlighter-rouge">hack_back_ckpt.rcS</code>. These files are covered in more depth in the
	chapter on full-system simulation.</dd>
	<dt><strong>common/</strong></dt>
	<dd>This directory contains a number of helper scripts and functions to
	create simulated systems. For instance, <code class="highlighter-rouge">Caches.py</code> is similar to
	the <code class="highlighter-rouge">caches.py</code> and <code class="highlighter-rouge">caches_opts.py</code> files created in previous
	chapters.

	<p><code class="highlighter-rouge">Options.py</code> contains a variety of options that can be set on the
	command line. Like the number of CPUs, system clock, and many, many
	more. This is a good place to look to see if the option you want to
	change already has a command line parameter.</p>

	<p><code class="highlighter-rouge">CacheConfig.py</code> contains the options and functions for setting
	cache parameters for the classic memory system.</p>

	<p><code class="highlighter-rouge">MemConfig.py</code> provides some helper functions for setting the memory
	system.</p>

	<p><code class="highlighter-rouge">FSConfig.py</code> contains the necessary functions to set up full-system
	simulation for many different kinds of systems. Full-system
	simulation is discussed further in it’s own chapter.</p>

	<p><code class="highlighter-rouge">Simulation.py</code> contains many helper functions to set up and run
	gem5. A lot of the code contained in this file manages saving and
	restoring checkpoints. The example configuration files below in
	<code class="highlighter-rouge">examples/</code> use the functions in this file to execute the gem5
	simulation. This file is quite complicated, but it also allows a lot
	of flexibility in how the simulation is run.</p>
	</dd>
	<dt><strong>dram/</strong></dt>
	<dd>Contains scripts to test DRAM.</dd>
	<dt><strong>example/</strong></dt>
	<dd>This directory contains some example gem5 configuration scripts that
	can be used out-of-the-box to run gem5. Specifically, <code class="highlighter-rouge">se.py</code> and
	<code class="highlighter-rouge">fs.py</code> are quite useful. More on these files can be found in the
	next section. There are also some other utility configuration
	scripts in this directory.</dd>
	<dt><strong>ruby/</strong></dt>
	<dd>This directory contains the configurations scripts for Ruby and its
	included cache coherence protocols. More details can be found in the
	chapter on Ruby.</dd>
	<dt><strong>splash2/</strong></dt>
	<dd>This directory contains scripts to run the splash2 benchmark suite
	with a few options to configure the simulated system.</dd>
	<dt><strong>topologies/</strong></dt>
	<dd>This directory contains the implementation of the topologies that
	can be used when creating the Ruby cache hierarchy. More details can
	be found in the chapter on Ruby.</dd>
	</dl>

	<h2 id="using-sepy-and-fspy">Using <code class="highlighter-rouge">se.py</code> and <code class="highlighter-rouge">fs.py</code></h2>

	<p>In this section, I’ll discuss some of the common options that can be
	passed on the command line to <code class="highlighter-rouge">se.py</code> and <code class="highlighter-rouge">fs.py</code>. More details on how
	to run full-system simulation can be found in the full-system simulation
	chapter. Here I’ll discuss the options that are common to the two files.</p>

	<p>Most of the options discussed in this section are found in Options.py
	and are registered in the function <code class="highlighter-rouge">addCommonOptions</code>. This section does
	not detail all of the options. To see all of the options, run the
	configuration script with <code class="highlighter-rouge">--help</code>, or read the script’s source code.</p>

	<p>First, let’s simply run the hello world program without any parameters:</p>

	<p>``` {.sourceCode .sh}
	build/X86/gem5.opt configs/example/se.py –cmd=tests/test-progs/hello/bin/x86/linux/hello</p>
	<div class="highlighter-rouge"><div class="highlight"><pre class="highlight"><code>
	And we get the following as output:

	gem5 Simulator System. http://gem5.org
	gem5 is copyrighted software; use the --copyright option for details.

	gem5 compiled Jan 14 2015 16:11:34
	gem5 started Feb 2 2015 15:22:24
	gem5 executing on mustardseed.cs.wisc.edu
	command line: build/X86/gem5.opt configs/example/se.py --cmd=tests/test-progs/hello/bin/x86/linux/hello
	Global frequency set at 1000000000000 ticks per second
	warn: DRAM device capacity (8192 Mbytes) does not match the address range assigned (512 Mbytes)
	0: system.remote_gdb.listener: listening for remote gdb #0 on port 7000
	** REAL SIMULATION **
	info: Entering event queue @ 0. Starting simulation...
	Hello world!
	Exiting @ tick 5942000 because target called exit()

	However, this isn't a very interesting simulation at all! By default,
	gem5 uses the atomic CPU and uses atomic memory accesses, so there's no
	real timing data reported! To confirm this, you can look at
	m5out/config.ini. The CPU is shown on line 46:

	[system.cpu]
	type=AtomicSimpleCPU
	children=apic_clk_domain dtb interrupts isa itb tracer workload
	branchPred=Null
	checker=Null
	clk_domain=system.cpu_clk_domain
	cpu_id=0
	do_checkpoint_insts=true
	do_quiesce=true
	do_statistics_insts=true

	To actually run gem5 in timing mode, let's specify a CPU type. While
	we're at it, we can also specify sizes for the L1 caches.

	``` {.sourceCode .sh}
	build/X86/gem5.opt configs/example/se.py --cmd=tests/test-progs/hello/bin/x86/linux/hello --cpu-type=TimingSimpleCPU --l1d_size=64kB --l1i_size=16kB
	</code></pre></div></div>

	<div class="highlighter-rouge"><div class="highlight"><pre class="highlight"><code>gem5 Simulator System. http://gem5.org
	gem5 is copyrighted software; use the --copyright option for details.

	gem5 compiled Jan 14 2015 16:11:34
	gem5 started Feb 2 2015 15:26:57
	gem5 executing on mustardseed.cs.wisc.edu
	command line: build/X86/gem5.opt configs/example/se.py --cmd=tests/test-progs/hello/bin/x86/linux/hello --cpu-type=TimingSimpleCPU --l1d_size=64kB --l1i_size=16kB
	Global frequency set at 1000000000000 ticks per second
	warn: DRAM device capacity (8192 Mbytes) does not match the address range assigned (512 Mbytes)
	0: system.remote_gdb.listener: listening for remote gdb #0 on port 7000
	** REAL SIMULATION **
	info: Entering event queue @ 0. Starting simulation...
	Hello world!
	Exiting @ tick 344986500 because target called exit()
	</code></pre></div></div>

	<p>Now, let’s check the config.ini file and make sure that these options
	propagated correctly to the final system. If you search
	<code class="highlighter-rouge">m5out/config.ini</code> for “cache”, you’ll find that no caches were created!
	Even though we specified the size of the caches, we didn’t specify that
	the system should use caches, so they weren’t created. The correct
	command line should be:</p>

	<p>``` {.sourceCode .sh}
	build/X86/gem5.opt configs/example/se.py –cmd=tests/test-progs/hello/bin/x86/linux/hello –cpu-type=TimingSimpleCPU –l1d_size=64kB –l1i_size=16kB –caches</p>
	<div class="highlighter-rouge"><div class="highlight"><pre class="highlight"><code>
	gem5 Simulator System. http://gem5.org
	gem5 is copyrighted software; use the --copyright option for details.

	gem5 compiled Jan 14 2015 16:11:34
	gem5 started Feb 2 2015 15:29:20
	gem5 executing on mustardseed.cs.wisc.edu
	command line: build/X86/gem5.opt configs/example/se.py --cmd=tests/test-progs/hello/bin/x86/linux/hello --cpu-type=TimingSimpleCPU --l1d_size=64kB --l1i_size=16kB --caches
	Global frequency set at 1000000000000 ticks per second
	warn: DRAM device capacity (8192 Mbytes) does not match the address range assigned (512 Mbytes)
	0: system.remote_gdb.listener: listening for remote gdb #0 on port 7000
	** REAL SIMULATION **
	info: Entering event queue @ 0. Starting simulation...
	Hello world!
	Exiting @ tick 29480500 because target called exit()

	On the last line, we see that the total time went from 344986500 ticks
	to 29480500, much faster! Looks like caches are probably enabled now.
	But, it's always a good idea to double check the `config.ini` file.

	[system.cpu.dcache]
	type=BaseCache
	children=tags
	addr_ranges=0:18446744073709551615
	assoc=2
	clk_domain=system.cpu_clk_domain
	demand_mshr_reserve=1
	eventq_index=0
	forward_snoops=true
	hit_latency=2
	is_top_level=true
	max_miss_count=0
	mshrs=4
	prefetch_on_access=false
	prefetcher=Null
	response_latency=2
	sequential_access=false
	size=65536
	system=system
	tags=system.cpu.dcache.tags
	tgts_per_mshr=20
	two_queue=false
	write_buffers=8
	cpu_side=system.cpu.dcache_port
	mem_side=system.membus.slave[2]

	Some common options `se.py` and `fs.py`
	---------------------------------------

	All of the possible options are printed when you run:

	``` {.sourceCode .sh}
	build/X86/gem5.opt configs/example/se.py --help
	</code></pre></div></div>

	<p>Below is a few important options from that list.</p>


	</div>

	</main>

	<script src="https://code.jquery.com/jquery-3.3.1.slim.min.js" integrity="sha384-q8i/X+965DzO0rT7abK41JStQIAqVgRVzpbzo5smXKp4YfRvH+8abtTE1Pi6jizo" crossorigin="anonymous"></script>
	<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.14.3/umd/popper.min.js" integrity="sha384-ZMP7rVo3mIykV+2+9J3UJ46jBk0WLaUAdn689aCwoqbBJiSnjAK/l8WvCWPIPm49" crossorigin="anonymous"></script>
	<script src="https://stackpath.bootstrapcdn.com/bootstrap/4.1.3/js/bootstrap.min.js" integrity="sha384-ChfqqxuZUCnJSK3+MXmPNIyE6ZbWh2IMqE241rYiqJxyMiZ6OW/JmZQ5stwEULTy" crossorigin="anonymous"></script>

	<script>
	// When the user scrolls down 20px from the top of the document, show the button
	window.onscroll = function() {scrollFunction()};

	function scrollFunction() {
	if (document.body.scrollTop > 100 \|\| document.documentElement.scrollTop > 20) {
	document.getElementById("myBtn").style.display = "block";
	} else {
	document.getElementById("myBtn").style.display = "none";
	}
	}

	// When the user clicks on the button, scroll to the top of the document
	function topFunction() {
	document.body.scrollTop = 0;
	document.documentElement.scrollTop = 0;
	}
	</script>

	</body>

	<footer class="page-footer">
	<div class="container">
	<div class="row">

	<div class="col-12 col-sm-4">
	<p><a href="/about">About</a></p>
	<p><a href="/publications">Publications</a></p>
	<p><a href="/contributing">Contributing</a></p>
	</div><br>

	<div class="col-12 col-sm-4">
	<p><a href="/gettingstarted">Documentation</a></p>
	<p><a href="#">Source</a></p>
	</div><br>

	<div class="col-12 col-sm-4">
	<p><a href="/help">Help</a></p>
	<p><a href="/search">Search</a></p>
	<p><a href="#">Mailing Lists</a></p>
	</div>

	</div>
	</div>
	</footer>


	</html>