sim: Remove FastAlloc

While FastAlloc provides a small performance increase (~1.5%) over regular malloc it isn't thread safe.
After removing FastAlloc and using tcmalloc I've seen a performance increase of 12% over libc malloc
when running twolf for ARM.

SConstruct

@@ -833,11 +833,6 @@ sticky_vars.AddVariables(
     ListVariable('CPU_MODELS', 'CPU models',
                  sorted(n for n,m in CpuModel.dict.iteritems() if m.default),
                  sorted(CpuModel.list)),
-    BoolVariable('NO_FAST_ALLOC', 'Disable fast object allocator', False),
-    BoolVariable('FORCE_FAST_ALLOC',
-                 'Enable fast object allocator, even for gem5.debug', False),
-    BoolVariable('FAST_ALLOC_STATS', 'Enable fast object allocator statistics',
-                 False),
     BoolVariable('EFENCE', 'Link with Electric Fence malloc debugger',
                  False),
     BoolVariable('SS_COMPATIBLE_FP',
@@ -852,8 +847,7 @@ sticky_vars.AddVariables(
     )
 
 # These variables get exported to #defines in config/*.hh (see src/SConscript).
-export_vars += ['USE_FENV', 'NO_FAST_ALLOC', 'FORCE_FAST_ALLOC',
+export_vars += ['USE_FENV', 'SS_COMPATIBLE_FP',
-                'FAST_ALLOC_STATS', 'SS_COMPATIBLE_FP',
                 'TARGET_ISA', 'CP_ANNOTATE', 'USE_POSIX_CLOCK' ]
 
 ###################################################

src/arch/x86/pagetable_walker.hh

@@ -44,7 +44,6 @@
 
 #include "arch/x86/pagetable.hh"
 #include "arch/x86/tlb.hh"
-#include "base/fast_alloc.hh"
 #include "base/types.hh"
 #include "mem/mem_object.hh"
 #include "mem/packet.hh"
@@ -86,7 +85,7 @@ namespace X86ISA
         WalkerPort port;
 
         // State to track each walk of the page table
-        class WalkerState : public FastAlloc
+        class WalkerState
         {
           private:
             enum State {

src/base/SConscript

@@ -40,7 +40,6 @@ Source('callback.cc')
 Source('circlebuf.cc')
 Source('cprintf.cc')
 Source('debug.cc')
-Source('fast_alloc.cc')
 if env['USE_FENV']:
     Source('fenv.c')
 Source('hostinfo.cc')

src/base/fast_alloc.cc

@@ -1,72 +0,0 @@
-/*
- * Copyright (c) 2000-2005 The Regents of The University of Michigan
- * 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.
- *
- * Authors: Steve Reinhardt
- */
-
-/*
- * This code was originally written by Steve Reinhardt as part of
- * the Wisconsin Wind Tunnel simulator.  Relicensed as part of M5
- * by permission.
- */
-
-#include <cassert>
-
-#include "base/fast_alloc.hh"
-
-#if USE_FAST_ALLOC
-
-void *FastAlloc::freeLists[Num_Buckets];
-
-#if FAST_ALLOC_STATS
-unsigned FastAlloc::newCount[Num_Buckets];
-unsigned FastAlloc::deleteCount[Num_Buckets];
-unsigned FastAlloc::allocCount[Num_Buckets];
-#endif
-
-void *
-FastAlloc::moreStructs(int bucket)
-{
-    assert(bucket > 0 && bucket < Num_Buckets);
-
-    int sz = bucket * Alloc_Quantum;
-    const int nstructs = Num_Structs_Per_New;   // how many to allocate?
-    char *p = ::new char[nstructs * sz];
-
-#if FAST_ALLOC_STATS
-    ++allocCount[bucket];
-#endif
-
-    freeLists[bucket] = p;
-    for (int i = 0; i < (nstructs-2); ++i, p += sz)
-        *(void **)p = p + sz;
-    *(void **)p = 0;
-
-    return (p + sz);
-}
-
-#endif // USE_FAST_ALLOC

src/base/fast_alloc.hh

@@ -1,190 +0,0 @@
-/*
- * Copyright (c) 2000-2001, 2003-2005 The Regents of The University of Michigan
- * 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.
- *
- * Authors: Steve Reinhardt
- */
-
-/*
- * This code was originally written by Steve Reinhardt as part of
- * the Wisconsin Wind Tunnel simulator.  Relicensed as part of M5
- * by permission.
- */
-
-#ifndef __BASE_FAST_ALLOC_HH__
-#define __BASE_FAST_ALLOC_HH__
-
-#include <cstddef>
-
-// Fast structure allocator.  Designed for small objects that are
-// frequently allocated and deallocated.  This code is derived from the
-// 'alloc_struct' package used in WWT and Blizzard.  C++ provides a
-// much nicer framework for the same optimization.  The package is
-// implemented as a class, FastAlloc.  Allocation and deletion are
-// performed using FastAlloc's new and delete operators.  Any object
-// that derives from the FastAlloc class will transparently use this
-// allocation package.
-
-// The static allocate() and deallocate() methods can also be called
-// directly if desired.
-
-// In order for derived classes to call delete with the correct
-// structure size even when they are deallocated via a base-type
-// pointer, they must have a virtual destructor.  It is sufficient for
-// FastAlloc to declare a virtual destructor (as it does); it is not
-// required for derived classes to declare their own destructor.  The
-// compiler will automatically generate a virtual destructor for each
-// derived class.  However, it is more efficient if each derived class
-// defines an inline destructor, so that the compiler can statically
-// collapse the destructor call chain back up the inheritance
-// hierarchy.
-
-#include "config/fast_alloc_stats.hh"
-#include "config/force_fast_alloc.hh"
-#include "config/no_fast_alloc.hh"
-
-// By default, we want to enable FastAlloc in any build other than
-// m5.debug.  (FastAlloc's reuse policies can mask allocation bugs, so
-// we typically want it disabled when debugging.)  Set
-// FORCE_FAST_ALLOC to enable even when debugging, and set
-// NO_FAST_ALLOC to disable even in non-debug builds.
-#define USE_FAST_ALLOC \
-    (FORCE_FAST_ALLOC || (!defined(DEBUG) && !NO_FAST_ALLOC))
-
-#if !USE_FAST_ALLOC
-
-class FastAlloc
-{
-};
-
-#else
-
-class FastAlloc
-{
-  public:
-    static void *allocate(size_t);
-    static void deallocate(void *, size_t);
-
-    void *operator new(size_t);
-    void operator delete(void *, size_t);
-
-    virtual ~FastAlloc() {}
-
-  private:
-
-    // Max_Alloc_Size is the largest object that can be allocated with
-    // this class.  There's no fundamental limit, but this limits the
-    // size of the freeLists array.  Let's not make this really huge
-    // like in Blizzard.
-    static const size_t Max_Alloc_Size = 512;
-
-    // Alloc_Quantum is the difference in size between adjacent
-    // buckets in the free list array.
-    static const int Log2_Alloc_Quantum = 3;
-    static const int Alloc_Quantum = (1 << Log2_Alloc_Quantum);
-
-    // Num_Buckets = bucketFor(Max_Alloc_Size) + 1
-    static const int Num_Buckets =
-        ((Max_Alloc_Size + Alloc_Quantum - 1) >> Log2_Alloc_Quantum) + 1;
-
-    // when we call new() for more structures, how many should we get?
-    static const int Num_Structs_Per_New = 20;
-
-    static int bucketFor(size_t);
-    static void *moreStructs(int bucket);
-
-    static void *freeLists[Num_Buckets];
-
-#if FAST_ALLOC_STATS
-    static unsigned newCount[Num_Buckets];
-    static unsigned deleteCount[Num_Buckets];
-    static unsigned allocCount[Num_Buckets];
-#endif
-};
-
-inline int
-FastAlloc::bucketFor(size_t sz)
-{
-    return (sz + Alloc_Quantum - 1) >> Log2_Alloc_Quantum;
-}
-
-inline void *
-FastAlloc::allocate(size_t sz)
-{
-    int b;
-    void *p;
-
-    if (sz > Max_Alloc_Size)
-        return (void *)::new char[sz];
-
-    b = bucketFor(sz);
-    p = freeLists[b];
-
-    if (p)
-        freeLists[b] = *(void **)p;
-    else
-        p = moreStructs(b);
-
-#if FAST_ALLOC_STATS
-    ++newCount[b];
-#endif
-
-    return p;
-}
-
-inline void
-FastAlloc::deallocate(void *p, size_t sz)
-{
-    int b;
-
-    if (sz > Max_Alloc_Size) {
-        ::delete [] (char *)p;
-        return;
-    }
-
-    b = bucketFor(sz);
-    *(void **)p = freeLists[b];
-    freeLists[b] = p;
-#if FAST_ALLOC_STATS
-    ++deleteCount[b];
-#endif
-}
-
-inline void *
-FastAlloc::operator new(size_t sz)
-{
-    return allocate(sz);
-}
-
-inline void
-FastAlloc::operator delete(void *p, size_t sz)
-{
-    deallocate(p, sz);
-}
-
-#endif // USE_FAST_ALLOC
-
-#endif // __BASE_FAST_ALLOC_HH__

src/cpu/base_dyn_inst.hh

@@ -51,7 +51,6 @@
 #include <queue>
 
 #include "arch/utility.hh"
-#include "base/fast_alloc.hh"
 #include "base/trace.hh"
 #include "config/the_isa.hh"
 #include "cpu/checker/cpu.hh"
@@ -73,7 +72,7 @@
  */
 
 template <class Impl>
-class BaseDynInst : public FastAlloc, public RefCounted
+class BaseDynInst : public RefCounted
 {
   public:
     // Typedef for the CPU.

src/cpu/inorder/inorder_dyn_inst.hh

@@ -41,7 +41,6 @@
 #include "arch/mt.hh"
 #include "arch/types.hh"
 #include "arch/utility.hh"
-#include "base/fast_alloc.hh"
 #include "base/trace.hh"
 #include "base/types.hh"
 #include "config/the_isa.hh"
@@ -73,7 +72,7 @@
 class ResourceRequest;
 class Packet;
 
-class InOrderDynInst : public FastAlloc, public RefCounted
+class InOrderDynInst : public RefCounted
 {
   public:
     // Binary machine instruction type.

src/cpu/o3/lsq_unit.hh

@@ -41,7 +41,6 @@
 #include "arch/isa_traits.hh"
 #include "arch/locked_mem.hh"
 #include "arch/mmapped_ipr.hh"
-#include "base/fast_alloc.hh"
 #include "base/hashmap.hh"
 #include "config/the_isa.hh"
 #include "cpu/inst_seq.hh"
@@ -271,7 +270,7 @@ class LSQUnit {
     MasterPort *dcachePort;
 
     /** Derived class to hold any sender state the LSQ needs. */
-    class LSQSenderState : public Packet::SenderState, public FastAlloc
+    class LSQSenderState : public Packet::SenderState
     {
       public:
         /** Default constructor. */

src/cpu/ozone/lw_lsq.hh

@@ -37,7 +37,6 @@
 #include <queue>
 
 #include "arch/types.hh"
-#include "base/fast_alloc.hh"
 #include "base/hashmap.hh"
 #include "config/the_isa.hh"
 #include "cpu/inst_seq.hh"
@@ -301,7 +300,7 @@ class OzoneLWLSQ {
     };
 
     /** Derived class to hold any sender state the LSQ needs. */
-    class LSQSenderState : public Packet::SenderState, public FastAlloc
+    class LSQSenderState : public Packet::SenderState
     {
       public:
         /** Default constructor. */

src/cpu/testers/memtest/memtest.hh

@@ -34,7 +34,6 @@
 
 #include <set>
 
-#include "base/fast_alloc.hh"
 #include "base/statistics.hh"
 #include "mem/mem_object.hh"
 #include "mem/port.hh"
@@ -112,7 +111,7 @@ class MemTest : public MemObject
     CpuPort funcPort;
     PortProxy funcProxy;
 
-    class MemTestSenderState : public Packet::SenderState, public FastAlloc
+    class MemTestSenderState : public Packet::SenderState
     {
       public:
         /** Constructor. */

src/cpu/testers/networktest/networktest.hh

@@ -33,7 +33,6 @@
 
 #include <set>
 
-#include "base/fast_alloc.hh"
 #include "base/statistics.hh"
 #include "mem/mem_object.hh"
 #include "mem/port.hh"
@@ -99,7 +98,7 @@ class NetworkTest : public MemObject
 
     CpuPort cachePort;
 
-    class NetworkTestSenderState : public Packet::SenderState, public FastAlloc
+    class NetworkTestSenderState : public Packet::SenderState
     {
       public:
         /** Constructor. */

src/dev/dma_device.hh

@@ -50,7 +50,7 @@
 class DmaPort : public MasterPort
 {
   protected:
-    struct DmaReqState : public Packet::SenderState, public FastAlloc
+    struct DmaReqState : public Packet::SenderState
     {
         /** Event to call on the device when this transaction (all packets)
          * complete. */

src/mem/bridge.hh

@@ -55,7 +55,6 @@
 #include <queue>
 #include <string>
 
-#include "base/fast_alloc.hh"
 #include "base/types.hh"
 #include "mem/mem_object.hh"
 #include "mem/packet.hh"
@@ -85,7 +84,7 @@ class Bridge : public MemObject
      * state and original source. It has enough information to also
      * restore the response once it comes back to the bridge.
      */
-    class RequestState : public Packet::SenderState, public FastAlloc
+    class RequestState : public Packet::SenderState
     {
 
       public:

src/mem/cache/cache_impl.hh

@@ -50,7 +50,6 @@
  * Cache definitions.
  */
 
-#include "base/fast_alloc.hh"
 #include "base/misc.hh"
 #include "base/range.hh"
 #include "base/types.hh"
@@ -349,7 +348,7 @@ Cache<TagStore>::access(PacketPtr pkt, BlkType *&blk,
 }
 
 
-class ForwardResponseRecord : public Packet::SenderState, public FastAlloc
+class ForwardResponseRecord : public Packet::SenderState
 {
     Packet::SenderState *prevSenderState;
     PortID prevSrc;

src/mem/packet.hh

@@ -58,7 +58,6 @@
 
 #include "base/cast.hh"
 #include "base/compiler.hh"
-#include "base/fast_alloc.hh"
 #include "base/flags.hh"
 #include "base/misc.hh"
 #include "base/printable.hh"
@@ -227,7 +226,7 @@ class MemCmd
  * ultimate destination and back, possibly being conveyed by several
  * different Packets along the way.)
  */
-class Packet : public FastAlloc, public Printable
+class Packet : public Printable
 {
   public:
     typedef uint32_t FlagsType;
@@ -358,7 +357,7 @@ class Packet : public FastAlloc, public Printable
      * Object used to maintain state of a PrintReq.  The senderState
      * field of a PrintReq should always be of this type.
      */
-    class PrintReqState : public SenderState, public FastAlloc
+    class PrintReqState : public SenderState
     {
       private:
         /**

src/mem/request.hh

@@ -42,7 +42,6 @@
 #include <cassert>
 #include <climits>
 
-#include "base/fast_alloc.hh"
 #include "base/flags.hh"
 #include "base/misc.hh"
 #include "base/types.hh"
@@ -53,7 +52,7 @@ class Request;
 typedef Request* RequestPtr;
 typedef uint16_t MasterID;
 
-class Request : public FastAlloc
+class Request
 {
   public:
     typedef uint32_t FlagsType;
@@ -229,7 +228,7 @@ class Request : public FastAlloc
         setThreadContext(cid, tid);
     }
 
-    ~Request() {}  // for FastAlloc
+    ~Request() {}
 
     /**
      * Set up CPU and thread numbers.

src/python/swig/event.i

@@ -73,7 +73,6 @@
 %include <std_string.i>
 %include <stdint.i>
 
-%import "base/fast_alloc.hh"
 %import "sim/serialize.hh"
 
 %include "base/types.hh"

src/sim/eventq.hh

@@ -42,7 +42,6 @@
 #include <iosfwd>
 #include <string>
 
-#include "base/fast_alloc.hh"
 #include "base/flags.hh"
 #include "base/misc.hh"
 #include "base/trace.hh"
@@ -61,7 +60,7 @@ extern EventQueue mainEventQueue;
  *
  * Caution, the order of members is chosen to maximize data packing.
  */
-class Event : public Serializable, public FastAlloc
+class Event : public Serializable
 {
     friend class EventQueue;