readme.cheetah

RISC处理器仿真分析程序。可以用于研究通用RISC处理器的指令和架构设计。在linux下编译

[Greetings, this is the README and man pages from the original Cheetah release
 by Rabin A. Sugumar and Santosh G. Abraham.  All cheetah sources are
 contained in the directory "libcheetah/".  The simulator "sim-cheetah"
 interfaces to the cheetah engine, and supports most of the options described
 below.]


Cheetah is a cache simulation package which can simulate various cache
configurations in a single pass through the address trace.
Specifically, Cheetah can simulate ranges of set-associative,
fully-associative or direct-mapped caches. Here are answers to some
common questions.

Why a package for cache simulation ?

It is fairly trivial to write a cache simulator which simulates one
cache at a time and outputs the miss ratio.  However, cache simulators
are typically used to simulate traces on several configurations, and
single cache simulators are inefficient and difficult to manage for
such purposes.

Cheetah uses extremely efficient single-pass algorithms to simulate
multiple cache configurations.  These algorithms exploit inclusion and
other properties that hold between cache configurations.  Therefore,
Cheetah has the potential to speed-up the cache evaluation process
significantly.

Additionally, Cheetah can simulate caches under OPT replacement [2].
Cache simulators for OPT are difficult to develop. Cheetah uses new
algorithms that we developed to perform single-pass simulation of
caches under OPT replacement efficiently.



How does Cheetah differ from other cache simulation packages like
'Dinero III' (developed by Mark Hill, and distributed with the
Hennessy-Patterson book on architecture) and 'Tycho' also developed by
Mark Hill ?

Dinero III (V3.3) simulates one set-associative cache configuration at
a time. In contrast, Cheetah simulates a range of set-associative or
fully-associative cache configurations at a time.  Further, Cheetah
can simulate OPT as well as LRU replacement; Dinero III can simulate
LRU, random and FIFO.  However, Dinero III simulates sub-block
placement, prefetch strategies and write effects. Currently, Cheetah
cannot simulate these features.
  
Tycho is a single pass simulator for multiple LRU set-associative
caches.  Tycho's capabilities are a subset of those of Cheetah.
Further, the algorithm [1] that Cheetah uses to do the set-associative
cache simulation is more efficient both in terms of simulation time
and memory requirements than the one used in Tycho.  Typically, on a
trace generated using the pixie tool (available on workstations based
on the MIPS processor), Cheetah is about six times faster than Tycho,
partly due to algorithmic improvements (2X) and partly due to
formatting overheads (3X).

The following publications describe the various algorithms used in
Cheetah in greater detail:

[1] Rabin A. Sugumar and Santosh G. Abraham, ``Efficient simulation
    of caches using binomial trees,'' Technical Report CSE-TR  1991.
[2] Rabin A. Sugumar and Santosh G. Abraham, ``Efficient simulation
    of caches under OPT replacement with applications to miss
    characterization,'' in the proceedings of the 1993 ACM SIGMETRICS
    conference.



What are the conditions of use ?

You are free to use this package as you wish. You should understand,
however, that although we have tried hard to ensure that the simulator
is accurate, we do not guarantee anything, and that this package is
distributed with absolutely no warranty.

You are also free to modify and distribute this package as you wish as
long as it is not for commercial gain. We ask that you retain our
copyright notice and make clear what your modifications were.
If you use the simulator extensively in any of your publications,
please reference one of the relevant papers above.

Also, if you use the simulator, we would like to hear from you to have a
rough idea of where it is being used. We could then inform you about
bug fixes and new versions of the package.  We would also like to hear
any comments you have on the simulator, and about any improvements you
make so that we can incorporate them in future releases.

We can be reached by email at [e-mail] or [e-mail] .


***********************************************************************************

Files in the directory

  COPYRIGHT  Copyright notice
  README     This file
  VERSION    Version number
  Makefile   Make file
  main.c     Common user interface
  saclru.c   LRU set-associative cache simulator.
  faclru.c   LRU fully-associative cache simulator.
  sacopt.c   OPT set-associative cache simulator.
  facopt.c   OPT fully-associative cache simulator.
  ppopt.c    Preprocessor for OPT simulators.
  dmvl.c     Variable line size direct-mapped cache simulator.
  ascbin.c   Conversion program. ASCII to basic binary format.
  pixie.c    Routine that converts pixie format to simulator format.
  din.c      Routine that converts DIN format to simulator format.
  utils.c    Some common functions used by the simulators.

  orig_results   Result file used to test installation.
  trace.ccom.Z   A sample trace in ASCII format. To run this on cheetah

                  uncompress trace.ccom
                  ascbin < trace.ccom > trace_file
		  cheetah -Fbasic -ftrace_file [other options]

  cheetah.1         Man page. To view: 'nroff -man cheetah.1' .


Installation
  'make cheetah' will make the simulator.
  'make test' will make the simulator and also test it on the sample trace.

--

     cheetah(1)                                             cheetah(1)



     NAME
          cheetah - Single-pass simulator for direct-mapped, set-
          associative and fully associative caches.

     SYNTAX
          cheetah [ -options ]

     DESCRIPTION
          cheetah is a cache simulation package which can simulate
          various cache configurations.  It is a collection of
          single-pass simulators which simulate ranges of direct-
          mapped,  set-associative and fully-associative caches.  The
          input to cheetah is a memory address trace in one of three
          formats:

          (i) A binary format where the trace is a sequence of four
          byte addresses.  This is the format that is actually used in
          the simulator, and hence no internal conversion step is
          required. If the trace format you have is not among those
          supported by cheetah it is most efficient to convert it to
          the binary format for use with cheetah.

          (ii) The pixie format, where the trace is as output by the
          pixie tool available on MIPS processor based workstations.

          (iii) The DIN format, developed by Mark Hill, and used by
          earlier cache simulators such as Tycho and Dinero III.

          cheetah outputs the miss ratios of the various caches
          simulated.

          cheetah uses efficient single-pass simulation algorithms,
          and so in each simulation run it can determine the miss-
          ratios of a range of cache configurations.  It exploits
          inclusion and other relations that hold between cache
          configurations to significantly speedup the simulation.
          When many cache configurations need to be simulated on
          several traces the use of cheetah should greatly improve the
          efficiency of the process over running a large number of
          simulations with simple one-cache-at-a-time simulators.
          Tycho (Mark Hill 1989) is an earlier cache simulation
          package that also used single-pass simulation algorithms for
          simulating multiple LRU set-associative caches. The
          capabilities of cheetah are a superset of those of Tycho.
          Further, the algorithm that cheetah uses to simulate set-
          associative caches is more efficient both in terms of
          simulation time and memory requirements that the one used in
          Tycho.

          cheetah can simulate caches under LRU and OPT replacement
          strategies.  With OPT replacement the set-associative
          simulators permit cache bypass.  That is, on a miss the



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     cheetah(1)                                             cheetah(1)



          referenced line is installed in cache only if its priority
          is high enough.  OPT replacement is done by doing a limited
          look-ahead in the trace and fixing errors in the stack using
          a stack repair procedure.

          For further details on the algorithms used in cheetah please
          see the publications referenced below.

     OPTIONS
          (If the option is not specified, the corresponding parameter
          takes a default value in all cases.)

          cheetah has four major options which set the replacement
          strategy, the cache configuration, the trace format and the
          trace type.

          -R repl
               Used to specify the replacement strategy.  Replacement
               policies that are currently supported are lru and opt.
               (default lru )

          -C config
               Used to specify the configuration. Configuration can be
               one of

               fa        Simulate fully-associative caches.

               sa        Simulate set-associative caches.

               dm        Simulate direct-mapped caches.  Direct-mapped
                         should be specified only if direct-mapped