ruby: set: reimplement using std::bitset

The current Set data structure is slow and therefore is being reimplemented
using std::bitset. A maximum limit of 64 is being set on the number of
controllers of each type.  This means that for simulating a system with more
controllers of a given type, one would need to change the value of the variable
NUMBER_BITS_PER_SET

4 files changed, 137 insertions, 420 deletions

diff --git a/src/mem/ruby/common/NetDest.hh b/src/mem/ruby/common/NetDest.hh
index e09be0c2c..69bfa8a3e 100644
--- a/src/mem/ruby/common/NetDest.hh
+++ b/src/mem/ruby/common/NetDest.hh
@@ -26,11 +26,6 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-// NetDest specifies the network destination of a Message
-// This is backward compatible with the Set class that was previously
-// used to specify network destinations.
-// NetDest supports both node networks and component networks
-
 #ifndef __MEM_RUBY_COMMON_NETDEST_HH__
 #define __MEM_RUBY_COMMON_NETDEST_HH__
 
@@ -40,6 +35,7 @@
 #include "mem/ruby/common/Set.hh"
 #include "mem/ruby/common/MachineID.hh"
 
+// NetDest specifies the network destination of a Message
 class NetDest
 {
   public:
diff --git a/src/mem/ruby/common/SConscript b/src/mem/ruby/common/SConscript
index 3c149388a..f8660da39 100644
--- a/src/mem/ruby/common/SConscript
+++ b/src/mem/ruby/common/SConscript
@@ -38,5 +38,4 @@ Source('Consumer.cc')
 Source('DataBlock.cc')
 Source('Histogram.cc')
 Source('NetDest.cc')
-Source('Set.cc')
 Source('SubBlock.cc')
diff --git a/src/mem/ruby/common/Set.cc b/src/mem/ruby/common/Set.cc
deleted file mode 100644
index 331aa569a..000000000
--- a/src/mem/ruby/common/Set.cc
+++ /dev/null
@@ -1,341 +0,0 @@
-/*
- * Copyright (c) 1999-2008 Mark D. Hill and David A. Wood
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions are
- * met: redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer;
- * redistributions in binary form must reproduce the above copyright
- * notice, this list of conditions and the following disclaimer in the
- * documentation and/or other materials provided with the distribution;
- * neither the name of the copyright holders nor the names of its
- * contributors may be used to endorse or promote products derived from
- * this software without specific prior written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- */
-
-// modified (rewritten) 05/20/05 by Dan Gibson to accomimdate FASTER
-// >32 bit set sizes
-
-#include <cassert>
-#include <cstdio>
-
-#include "base/misc.hh"
-#include "mem/ruby/common/Set.hh"
-
-Set::Set()
-{
-    m_p_nArray = NULL;
-    m_nArrayLen = 0;
-    m_nSize = 0;
-}
-
-Set::Set(const Set& obj)
-{
-    m_p_nArray = NULL;
-    setSize(obj.m_nSize);
-
-    // copy from the host to this array
-    for (int i = 0; i < m_nArrayLen; i++)
-        m_p_nArray[i] = obj.m_p_nArray[i];
-}
-
-Set::Set(int size)
-{
-    m_p_nArray = NULL;
-    m_nArrayLen = 0;
-    m_nSize = 0;
-    if (size > 0)
-        setSize(size);
-}
-
-Set::~Set()
-{
-    if (m_p_nArray && m_p_nArray != &m_p_nArray_Static[0])
-        delete [] m_p_nArray;
-    m_p_nArray = NULL;
-}
-
-void
-Set::clearExcess()
-{
-    // now just ensure that no bits over the maximum size were set
-#ifdef _LP64
-    unsigned long mask = 0x7FFFFFFFFFFFFFFF;
-#else
-    unsigned long mask = 0x7FFFFFFF;
-#endif
-
-    // the number of populated spaces in the higest-order array slot
-    // is: m_nSize % LONG_BITS, so the uppermost LONG_BITS -
-    // m_nSize%64 bits should be cleared
-    if ((m_nSize % LONG_BITS) != 0) {
-        for (int j = 0; j < 64 - (m_nSize & INDEX_MASK); j++) {
-            m_p_nArray[m_nArrayLen - 1] &= mask;
-            mask = mask >> 1;
-        }
-    }
-}
-
-
-/*
- * This function should set all the bits in the current set that are
- * already set in the parameter set
- */
-void
-Set::addSet(const Set& set)
-{
-    assert(getSize()==set.getSize());
-    for (int i = 0; i < m_nArrayLen; i++)
-        m_p_nArray[i] |= set.m_p_nArray[i];
-}
-
-/*
- * This function clears bits that are =1 in the parameter set
- */
-void
-Set::removeSet(const Set& set)
-{
-    assert(m_nSize == set.m_nSize);
-    for (int i = 0; i < m_nArrayLen; i++)
-        m_p_nArray[i] &= ~set.m_p_nArray[i];
-}
-
-/*
- * this function sets all bits in the set
- */
-void
-Set::broadcast()
-{
-    for (int i = 0; i < m_nArrayLen; i++)
-        m_p_nArray[i] = -1; // note that -1 corresponds to all 1's in 2's comp.
-
-    clearExcess();
-}
-
-/*
- * This function returns the population count of 1's in the set
- */
-int
-Set::count() const
-{
-    int counter = 0;
-
-    for (int i = 0; i < m_nArrayLen; i++) {
-        unsigned long mask = 0x01;
-
-        for (int j = 0; j < LONG_BITS; j++) {
-            // FIXME - significant performance loss when array
-            // population << LONG_BITS
-            if ((m_p_nArray[i] & mask) != 0) {
-                counter++;
-            }
-            mask = mask << 1;
-        }
-    }
-
-    return counter;
-}
-
-/*
- * This function checks for set equality
- */
-bool
-Set::isEqual(const Set& set) const
-{
-    assert(m_nSize == set.m_nSize);
-
-    for (int i = 0; i < m_nArrayLen; i++)
-        if (m_p_nArray[i] != set.m_p_nArray[i])
-            return false;
-
-    return true;
-}
-
-/*
- * This function returns the NodeID (int) of the least set bit
- */
-NodeID
-Set::smallestElement() const
-{
-    assert(count() > 0);
-    for (int i = 0; i < m_nArrayLen; i++) {
-        if (m_p_nArray[i] != 0) {
-            // the least-set bit must be in here
-            unsigned long x = m_p_nArray[i];
-
-            for (int j = 0; j < LONG_BITS; j++) {
-                if (x & 1) {
-                    return LONG_BITS * i + j;
-                }
-
-                x = x >> 1;
-            }
-
-            panic("No smallest element of an empty set.");
-        }
-    }
-
-    panic("No smallest element of an empty set.");
-}
-
-/*
- * this function returns true iff all bits are set
- */
-bool
-Set::isBroadcast() const
-{
-    // check the fully-loaded words by equal to 0xffffffff
-    // only the last word may not be fully loaded, it is not
-    // fully loaded iff m_nSize % 32 or 64 !=0 => fully loaded iff
-    // m_nSize % 32 or 64 == 0
-
-    int max = (m_nSize % LONG_BITS) == 0 ? m_nArrayLen : m_nArrayLen - 1;
-    for (int i = 0; i < max; i++) {
-        if (m_p_nArray[i] != -1) {
-            return false;
-        }
-    }
-
-    // now check the last word, which may not be fully loaded
-    unsigned long mask = 1;
-    for (int j = 0; j < (m_nSize % LONG_BITS); j++) {
-        if ((mask & m_p_nArray[m_nArrayLen-1]) == 0) {
-            return false;
-        }
-        mask = mask << 1;
-    }
-
-    return true;
-}
-
-/*
- * this function returns true iff no bits are set
- */
-bool
-Set::isEmpty() const
-{
-    // here we can simply check if all = 0, since we ensure
-    // that "extra slots" are all zero
-    for (int i = 0; i < m_nArrayLen ; i++)
-        if (m_p_nArray[i])
-            return false;
-
-    return true;
-}
-
-// returns the logical OR of "this" set and orSet
-Set
-Set::OR(const Set& orSet) const
-{
-    Set result(m_nSize);
-    assert(m_nSize == orSet.m_nSize);
-    for (int i = 0; i < m_nArrayLen; i++)
-        result.m_p_nArray[i] = m_p_nArray[i] | orSet.m_p_nArray[i];
-
-    return result;
-}
-
-// returns the logical AND of "this" set and andSet
-Set
-Set::AND(const Set& andSet) const
-{
-    Set result(m_nSize);
-    assert(m_nSize == andSet.m_nSize);
-
-    for (int i = 0; i < m_nArrayLen; i++) {
-        result.m_p_nArray[i] = m_p_nArray[i] & andSet.m_p_nArray[i];
-    }
-
-    return result;
-}
-
-/*
- * Returns false if a bit is set in the parameter set that is NOT set
- * in this set
- */
-bool
-Set::isSuperset(const Set& test) const
-{
-    assert(m_nSize == test.m_nSize);
-
-    for (int i = 0; i < m_nArrayLen; i++)
-        if (((test.m_p_nArray[i] & m_p_nArray[i]) | ~test.m_p_nArray[i]) != -1)
-            return false;
-
-    return true;
-}
-
-void
-Set::setSize(int size)
-{
-    m_nSize = size;
-    m_nArrayLen = (m_nSize + LONG_BITS - 1) / LONG_BITS;
-
-    // decide whether to use dynamic or static alloction
-    if (m_nArrayLen <= NUMBER_WORDS_PER_SET) {
-        // constant defined in RubySystem.hh
-        // its OK to use the static allocation, and it will
-        // probably be faster (as m_nArrayLen is already in the
-        // cache and they will probably share the same cache line)
-
-        // if switching from dyanamic to static allocation (which
-        // is probably rare, but why not be complete?), must delete
-        // the dynamically allocated space
-        if (m_p_nArray && m_p_nArray != &m_p_nArray_Static[0])
-            delete [] m_p_nArray;
-
-        m_p_nArray = &m_p_nArray_Static[0];
-    } else {
-        // can't use static allocation...simply not enough room
-        // so dynamically allocate some space
-        if (m_p_nArray && m_p_nArray != &m_p_nArray_Static[0])
-            delete [] m_p_nArray;
-
-        m_p_nArray = new unsigned long[m_nArrayLen];
-    }
-
-    clear();
-}
-
-Set&
-Set::operator=(const Set& obj)
-{
-    if (this != &obj) {
-        // resize this item
-        setSize(obj.getSize());
-
-        // copy the elements from obj to this
-        for (int i = 0; i < m_nArrayLen; i++)
-            m_p_nArray[i] = obj.m_p_nArray[i];
-    }
-
-    return *this;
-}
-
-void
-Set::print(std::ostream& out) const
-{
-    if (!m_p_nArray) {
-        out << "[Set {Empty}]";
-        return;
-    }
-
-    out << "[Set (" << m_nSize << ")";
-    for (int i = m_nArrayLen - 1; i >= 0; i--) {
-        out << csprintf(" 0x%08X", m_p_nArray[i]);
-    }
-    out << " ]";
-}
diff --git a/src/mem/ruby/common/Set.hh b/src/mem/ruby/common/Set.hh
index e97385e5e..3ab6979d4 100644
--- a/src/mem/ruby/common/Set.hh
+++ b/src/mem/ruby/common/Set.hh
@@ -32,129 +32,192 @@
 #ifndef __MEM_RUBY_COMMON_SET_HH__
 #define __MEM_RUBY_COMMON_SET_HH__
 
+#include <bitset>
+#include <cassert>
 #include <iostream>
-#include <limits>
 
+#include "base/misc.hh"
 #include "mem/ruby/common/TypeDefines.hh"
 
-/*
- * This defines the number of longs (32-bits on 32 bit machines,
- * 64-bit on 64-bit AMD machines) to use to hold the set...
- * the default is 4, allowing 128 or 256 different members
- * of the set.
- *
- * This should never need to be changed for correctness reasons,
- * though increasing it will increase performance for larger
- * set sizes at the cost of a (much) larger memory footprint
- *
- */
-const int NUMBER_WORDS_PER_SET = 1;
+// Change for systems with more than 64 controllers of a particular type.
+const int NUMBER_BITS_PER_SET = 64;
 
 class Set
 {
   private:
-    int m_nSize;              // the number of bits in this set
-    int m_nArrayLen;          // the number of 32-bit words that are
-                              // held in the array
-
-    // Changed 5/24/05 for static allocation of array
-    // note that "long" corresponds to 32 bits on a 32-bit machine,
-    // 64 bits if the -m64 parameter is passed to g++, which it is
-    // for an AMD opteron under our configuration
-
-    // an word array to hold the bits in the set
-    unsigned long *m_p_nArray;
-    unsigned long m_p_nArray_Static[NUMBER_WORDS_PER_SET];
+    // Number of bits in use in this set.
+    int m_nSize;
+    std::bitset<NUMBER_BITS_PER_SET> bits;
 
-    static const int LONG_BITS =
-        std::numeric_limits<unsigned long>::digits + 1;
-    static const int INDEX_SHIFT = LONG_BITS == 64 ? 6 : 5;
-    static const int INDEX_MASK = (1 << INDEX_SHIFT) - 1;
+  public:
+    Set() : m_nSize(0) {}
 
-    void clearExcess();
+    Set(int size) : m_nSize(size)
+    {
+        if (size > NUMBER_BITS_PER_SET)
+            fatal("Number of bits(%d) < size specified(%d). "
+                  "Increase the number of bits and recompile.\n",
+                  NUMBER_BITS_PER_SET, size);
+    }
 
-  public:
-    Set();
-    Set(int size);
-    Set(const Set& obj);
-    ~Set();
+    Set(const Set& obj) : m_nSize(obj.m_nSize), bits(obj.bits) {}
+    ~Set() {}
 
-    Set& operator=(const Set& obj);
+    Set& operator=(const Set& obj)
+    {
+        m_nSize = obj.m_nSize;
+        bits = obj.bits;
+        return *this;
+    }
 
     void
     add(NodeID index)
     {
-        m_p_nArray[index >> INDEX_SHIFT] |=
-            (((unsigned long) 1) << (index & INDEX_MASK));
+        bits.set(index);
     }
 
-    void addSet(const Set& set);
+    /*
+     * This function should set all the bits in the current set that are
+     * already set in the parameter set
+     */
+    void
+    addSet(const Set& obj)
+    {
+        assert(m_nSize == obj.m_nSize);
+        bits |= obj.bits;
+    }
 
+    /*
+     * This function clears bits that are =1 in the parameter set
+     */
     void
     remove(NodeID index)
     {
-        m_p_nArray[index >> INDEX_SHIFT] &=
-            ~(((unsigned long)1) << (index & INDEX_MASK));
+        bits.reset(index);
     }
 
-    void removeSet(const Set& set);
-
+    /*
+     * This function clears bits that are =1 in the parameter set
+     */
     void
-    clear()
+    removeSet(const Set& obj)
     {
-        for (int i = 0; i < m_nArrayLen; i++)
-            m_p_nArray[i] = 0;
+        assert(m_nSize == obj.m_nSize);
+        bits &= (~obj.bits);
     }
 
-    void broadcast();
-    int count() const;
-    bool isEqual(const Set& set) const;
+    void clear() { bits.reset(); }
+
+    /*
+     * this function sets all bits in the set
+     */
+    void broadcast()
+    {
+        bits.set();
+        for (int j = m_nSize; j < NUMBER_BITS_PER_SET; ++j) {
+            bits.reset(j);
+        }
+    }
+
+    /*
+     * This function returns the population count of 1's in the set
+     */
+    int count() const { return bits.count(); }
+
+    /*
+     * This function checks for set equality
+     */
+    bool
+    isEqual(const Set& obj) const
+    {
+        assert(m_nSize == obj.m_nSize);
+        return bits == obj.bits;
+    }
 
     // return the logical OR of this set and orSet
-    Set OR(const Set& orSet) const;
+    Set
+    OR(const Set& obj) const
+    {
+        assert(m_nSize == obj.m_nSize);
+        Set r(m_nSize);
+        r.bits = bits | obj.bits;
+        return r;
+    };
 
     // return the logical AND of this set and andSet
-    Set AND(const Set& andSet) const;
+    Set
+    AND(const Set& obj) const
+    {
+        assert(m_nSize == obj.m_nSize);
+        Set r(m_nSize);
+        r.bits = bits & obj.bits;
+        return r;
+    }
 
     // Returns true if the intersection of the two sets is empty
     bool
-    intersectionIsEmpty(const Set& other_set) const
+    intersectionIsEmpty(const Set& obj) const
     {
-        for (int i = 0; i < m_nArrayLen; i++)
-            if (m_p_nArray[i] & other_set.m_p_nArray[i])
-                return false;
-        return true;
+        std::bitset<NUMBER_BITS_PER_SET> r = bits & obj.bits;
+        return r.none();
     }
 
-    bool isSuperset(const Set& test) const;
-    bool isSubset(const Set& test) const { return test.isSuperset(*this); }
-
+    /*
+     * Returns false if a bit is set in the parameter set that is NOT set
+     * in this set
+     */
     bool
-    isElement(NodeID element) const
+    isSuperset(const Set& test) const
     {
-        return (m_p_nArray[element>>INDEX_SHIFT] &
-            (((unsigned long)1) << (element & INDEX_MASK))) != 0;
+        assert(m_nSize == test.m_nSize);
+        std::bitset<NUMBER_BITS_PER_SET> r = bits | test.bits;
+        return (r == bits);
     }
 
-    bool isBroadcast() const;
-    bool isEmpty() const;
+    bool isSubset(const Set& test) const { return test.isSuperset(*this); }
+
+    bool isElement(NodeID element) const { return bits.test(element); }
 
-    NodeID smallestElement() const;
+    /*
+     * this function returns true iff all bits in use are set
+     */
+    bool
+    isBroadcast() const
+    {
+        return (bits.count() == m_nSize);
+    }
 
-    void setSize(int size);
+    bool isEmpty() const { return bits.none(); }
 
-    NodeID
-    elementAt(int index) const
+    NodeID smallestElement() const
     {
-        if (isElement(index))
-            return (NodeID)true;
-        else
-            return 0;
+        for (int i = 0; i < m_nSize; ++i) {
+            if (bits.test(i)) {
+                return i;
+            }
+        }
+        panic("No smallest element of an empty set.");
     }
 
+    bool elementAt(int index) const { return bits[index]; }
+
     int getSize() const { return m_nSize; }
 
-    void print(std::ostream& out) const;
+    void
+    setSize(int size)
+    {
+        if (size > NUMBER_BITS_PER_SET)
+            fatal("Number of bits(%d) < size specified(%d). "
+                  "Increase the number of bits and recompile.\n",
+                  NUMBER_BITS_PER_SET, size);
+        m_nSize = size;
+        bits.reset();
+    }
+
+    void print(std::ostream& out) const
+    {
+        out << "[Set (" << m_nSize << "): " << bits << "]";
+    }
 };
 
 inline std::ostream&