ruby: add a prefetcher

Information
Submitter:	Nilay Vaish
Repository:	gem5
Branch:	default
Bugs:
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Description

Changeset 9312:0c088aab5fdf
---------------------------
ruby: add a prefetcher
This patch adds a prefetcher for the ruby memory system. The prefetcher
is based on a prefetcher implemented by others (well, I don't know
who wrote the original). The prefetcher does stride-based prefetching,
both unit and non-unit. It obseves the misses in the cache and trains on
these. After the training period is over, the prefetcher starts issuing
prefetch requests to the controller.

Testing Done

Issue Summary

Description	From	Last Updated	Status
next_stride_address, and page_address are not defined in this patch, nor at the head of the current repo.	Malek Musleh	Oct. 28, 2012, 11:08 a.m.	Resolved

I haven't had a chance to review all the patches you just sent out, but this one definitely caught my eye.  Can you describe how the prefetcher ties into the protocol?  Do you have an example protocol that you can show us?  As you probably know, we've integrated prefetchers into Ruby before, but they end up requiring protocol specific changes.  It is fine if this does at as.  I'm just curious to know if you thought about an easier way to make prefetching protocol independent yet still accurate.  BTW, have you ever wondered why the mandatory queue is called "mandatory"?  There use to be an optional queue included in each protocol file.  :)

src/mem/ruby/structures/Prefetcher.cc (Diff revision 1)

next_stride_address, and page_address are not defined in this patch, nor at the head of the current repo.

Show all issues

Nilay Vaish Oct. 28, 2012, 11:08 a.m. (Oct. 28, 2012, 11:08 a.m.)
```
Take a look at review request 1485.
```

rishabh srivastava Dec. 9, 2012, 11:22 a.m. (Dec. 9, 2012, 11:22 a.m.)

Hi Nilay.

Referred to the review reques 1485 and 1486 and made the requested changes accordingly for PARSEC benchmark.

The build of the gem5 was successful but when I ran MESI in the ruby.stats it showed no. of prefetches to be 0.

Do you have any idea on what can lead to that? and how i can resolve it.

BR//

Rishabh

Does any one has any other comments about these patches on prefetching?

Pramit Nandy Dec. 4, 2012, 3:24 p.m. (Dec. 4, 2012, 3:24 p.m.)

After adding this patch I tried to build using the command: scons ./build/X86/gem5.opt –j4. I got this error:

 [     CXX] X86/mem/ruby/system/RubyPortProxy.cc -> .o

 [     CXX] X86/mem/ruby/system/Sequencer.cc -> .o
 
 [     CXX] X86/mem/ruby/system/System.cc -> .o

 [     CXX] X86/mem/ruby/system/TimerTable.cc -> .o

 [     CXX] X86/mem/ruby/system/BankedArray.cc -> .o

 [ TRACING]  -> X86/debug/RubyPrefetcher.hh
 
 [SO PARAM] Prefetcher -> X86/params/Prefetcher.hh

 [     CXX] X86/mem/ruby/structures/Prefetcher.cc -> .o

build/X86/mem/ruby/structures/Prefetcher.cc: In constructor 'Prefetcher::Prefetcher(const Prefetcher::Params*)':
 
build/X86/mem/ruby/structures/Prefetcher.cc:16: error: class 'Prefetcher' does not have any field named 'm_negative_filter'

build/X86/mem/ruby/structures/Prefetcher.cc:17: error: class 'Prefetcher' does not have any field named 'm_nonunit_filter'
 
build/X86/mem/ruby/structures/Prefetcher.cc:24: error: 'm_unit_filter_hit' was not declared in this scope

build/X86/mem/ruby/structures/Prefetcher.cc:29: error: 'm_negative_filter_index' was not declared in this scope
 
build/X86/mem/ruby/structures/Prefetcher.cc:30: error: 'm_negative_filter_hit' was not declared in this scope

build/X86/mem/ruby/structures/Prefetcher.cc:36: error: 'm_nonunit_stride' was not declared in this scope
 
build/X86/mem/ruby/structures/Prefetcher.cc: In destructor 'virtual Prefetcher::~Prefetcher()':

build/X86/mem/ruby/structures/Prefetcher.cc:45: error: 'm_unit_filter_hit' was not declared in this scope
 
build/X86/mem/ruby/structures/Prefetcher.cc:46: error: 'm_negative_filter_hit' was not declared in this scope

build/X86/mem/ruby/structures/Prefetcher.cc:47: error: 'm_nonunit_stride' was not declared in this scope
 
build/X86/mem/ruby/structures/Prefetcher.cc: In member function 'void Prefetcher::observeMiss(const Address&, const RubyRequestType&)':

build/X86/mem/ruby/structures/Prefetcher.cc:121: error: 'm_unit_filter_hit' was not declared in this scope
 
build/X86/mem/ruby/structures/Prefetcher.cc:131: error: 'm_negative_filter' was not declared in this scope

build/X86/mem/ruby/structures/Prefetcher.cc:131: error: 'm_negative_filter_hit' was not declared in this scope
 
build/X86/mem/ruby/structures/Prefetcher.cc:132: error: 'm_negative_filter_index' was not declared in this scope

build/X86/mem/ruby/structures/Prefetcher.cc: In member function 'void Prefetcher::issueNextPrefetch(const Address&, PrefetchEntry*)':
 
build/X86/mem/ruby/structures/Prefetcher.cc:181: error: 'page_address' was not declared in this scope

build/X86/mem/ruby/structures/Prefetcher.cc:183: error: 'next_stride_address' was not declared in this scope
 
build/X86/mem/ruby/structures/Prefetcher.cc: In member function 'void Prefetcher::clearNonunitEntry(uint32_t)':

build/X86/mem/ruby/structures/Prefetcher.cc:219: error: 'm_nonunit_filter' was not declared in this scope
 
build/X86/mem/ruby/structures/Prefetcher.cc:220: error: 'm_nonunit_stride' was not declared in this scope

build/X86/mem/ruby/structures/Prefetcher.cc: In member function 'void Prefetcher::initializeStream(const Address&, int, uint32_t, const RubyRequestType&)':
 
build/X86/mem/ruby/structures/Prefetcher.cc:236: error: 'page_address' was not declared in this scope

build/X86/mem/ruby/structures/Prefetcher.cc:241: error: 'next_stride_address' was not declared in this scope
 
build/X86/mem/ruby/structures/Prefetcher.cc: In member function 'PrefetchEntry* Prefetcher::getPrefetchEntry(const Address&, uint32_t&)':

build/X86/mem/ruby/structures/Prefetcher.cc:269: error: 'next_stride_address' was not declared in this scope
 
build/X86/mem/ruby/structures/Prefetcher.cc: In member function 'bool Prefetcher::accessUnitFilter(std::vector<Address, std::allocator<Address> >&, uint32_t*, uint32_t&, const Address&, int, bool&)':
 
build/X86/mem/ruby/structures/Prefetcher.cc:287: error: 'next_stride_address' was not declared in this scope

build/X86/mem/ruby/structures/Prefetcher.cc:297: error: 'next_stride_address' was not declared in this scope
 
build/X86/mem/ruby/structures/Prefetcher.cc: In member function 'bool Prefetcher::accessNonunitFilter(const Address&, int*, bool&)':

build/X86/mem/ruby/structures/Prefetcher.cc:313: error: 'page_address' was not declared in this scope
 
build/X86/mem/ruby/structures/Prefetcher.cc:316: error: 'm_nonunit_filter' was not declared in this scope

build/X86/mem/ruby/structures/Prefetcher.cc:323: error: 'm_nonunit_stride' was not declared in this scope
 
build/X86/mem/ruby/structures/Prefetcher.cc:341: error: 'm_nonunit_stride' was not declared in this scope

build/X86/mem/ruby/structures/Prefetcher.cc:350: error: 'm_nonunit_filter' was not declared in this scope
 
build/X86/mem/ruby/structures/Prefetcher.cc:351: error: 'm_nonunit_stride' was not declared in this scope

build/X86/mem/ruby/structures/Prefetcher.cc: In member function 'void Prefetcher::print(std::ostream&) const':
 
build/X86/mem/ruby/structures/Prefetcher.cc:370: error: 'm_negative_filter' was not declared in this scope

build/X86/mem/ruby/structures/Prefetcher.cc:375: error: 'm_nonunit_filter' was not declared in this scope
 
build/X86/mem/ruby/structures/Prefetcher.cc:376: error: 'm_nonunit_stride' was not declared in this scope

scons: *** [build/X86/mem/ruby/structures/Prefetcher.o] Error 1

 [    SWIG] X86/python/m5/internal/NetworkLink_vector.i -> _wrap.cc, .py
 
scons: building terminated because of errors. 

It seems that these variables have not been defined/included in Prefetcher.cc. Where are these class variables defined? Do I have to make changes to some other files where these variables have been defined?

Thanks!!!

Pramit Nandy Dec. 5, 2012, 6:06 a.m. (Dec. 5, 2012, 6:06 a.m.)

When I tried first, it did bot build, which I realized after emailing you. After building, I got the above errors. I did not make changes anywhere else. Since, it shows the above errors after building, I am wondering if I need to make any other changes/addition apart from the patches given in this post?

Thanks for all the comments.  Well Done!  This looks good to me.

Looks good to me. Why did you choose to add a new directory? Are there other things that you see being added to, or moved into ruby/structures? Is there a difference between what goes in ruby/structures vs ruby/system?

You have a pending review.

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Issue Summary

Status: Closed (submitted)