gem5/src/mem/cache/tags/iic.cc
Koan-Sin Tan 7d4f187700 clang: Enable compiling gem5 using clang 2.9 and 3.0
This patch adds the necessary flags to the SConstruct and SConscript
files for compiling using clang 2.9 and later (on Ubuntu et al and OSX
XCode 4.2), and also cleans up a bunch of compiler warnings found by
clang. Most of the warnings are related to hidden virtual functions,
comparisons with unsigneds >= 0, and if-statements with empty
bodies. A number of mismatches between struct and class are also
fixed. clang 2.8 is not working as it has problems with class names
that occur in multiple namespaces (e.g. Statistics in
kernel_stats.hh).

clang has a bug (http://llvm.org/bugs/show_bug.cgi?id=7247) which
causes confusion between the container std::set and the function
Packet::set, and this is currently addressed by not including the
entire namespace std, but rather selecting e.g. "using std::vector" in
the appropriate places.
2012-01-31 12:05:52 -05:00

650 lines
18 KiB
C++

/*
* Copyright (c) 2002-2005 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: Erik Hallnor
*/
/**
* @file
* Definitions of the Indirect Index Cache tagstore.
*/
#include <algorithm>
#include <cmath>
#include <string>
#include <vector>
#include "base/intmath.hh"
#include "base/trace.hh"
#include "debug/Cache.hh"
#include "debug/IIC.hh"
#include "debug/IICMore.hh"
#include "mem/cache/tags/iic.hh"
#include "mem/cache/base.hh"
#include "sim/core.hh"
using namespace std;
/** Track the number of accesses to each cache set. */
#define PROFILE_IIC 1
IIC::IIC(IIC::Params &params) :
hashSets(params.numSets), blkSize(params.blkSize), assoc(params.assoc),
hitLatency(params.hitLatency), subSize(params.subblockSize),
numSub(blkSize/subSize),
trivialSize((floorLog2(params.size/subSize)*numSub)/8),
tagShift(floorLog2(blkSize)), blkMask(blkSize - 1),
subShift(floorLog2(subSize)), subMask(numSub - 1),
hashDelay(params.hashDelay),
numTags(hashSets * assoc + params.size/blkSize -1),
numSecondary(params.size/blkSize),
tagNull(numTags),
primaryBound(hashSets * assoc)
{
// Check parameters
if (blkSize < 4 || !isPowerOf2(blkSize)) {
fatal("Block size must be at least 4 and a power of 2");
}
if (hashSets <= 0 || !isPowerOf2(hashSets)) {
fatal("# of hashsets must be non-zero and a power of 2");
}
if (assoc <= 0) {
fatal("associativity must be greater than zero");
}
if (hitLatency <= 0) {
fatal("access latency must be greater than zero");
}
if (numSub*subSize != blkSize) {
fatal("blocksize must be evenly divisible by subblock size");
}
// debug stuff
freeSecond = numSecondary;
warmedUp = false;
warmupBound = params.size/blkSize;
numBlocks = params.size/subSize;
// Replacement Policy Initialization
repl = params.rp;
repl->setIIC(this);
//last_miss_time = 0
// allocate data reference counters
dataReferenceCount = new int[numBlocks];
memset(dataReferenceCount, 0, numBlocks*sizeof(int));
// Allocate storage for both internal data and block fast access data.
// We allocate it as one large chunk to reduce overhead and to make
// deletion easier.
unsigned data_index = 0;
dataStore = new uint8_t[(numBlocks + numTags) * blkSize];
dataBlks = new uint8_t*[numBlocks];
for (unsigned i = 0; i < numBlocks; ++i) {
dataBlks[i] = &dataStore[data_index];
freeDataBlock(i);
data_index += subSize;
}
assert(data_index == numBlocks * subSize);
// allocate and init tag store
tagStore = new IICTag[numTags];
unsigned blkIndex = 0;
// allocate and init sets
sets = new IICSet[hashSets];
for (unsigned i = 0; i < hashSets; ++i) {
sets[i].assoc = assoc;
sets[i].tags = new IICTag*[assoc];
sets[i].chain_ptr = tagNull;
for (unsigned j = 0; j < assoc; ++j) {
IICTag *tag = &tagStore[blkIndex++];
tag->chain_ptr = tagNull;
tag->data_ptr.resize(numSub);
tag->size = blkSize;
tag->trivialData = new uint8_t[trivialSize];
tag->numData = 0;
sets[i].tags[j] = tag;
tag->set = i;
tag->data = &dataStore[data_index];
data_index += blkSize;
}
}
assert(blkIndex == primaryBound);
for (unsigned i = primaryBound; i < tagNull; i++) {
tagStore[i].chain_ptr = i+1;
//setup data ptrs to subblocks
tagStore[i].data_ptr.resize(numSub);
tagStore[i].size = blkSize;
tagStore[i].trivialData = new uint8_t[trivialSize];
tagStore[i].numData = 0;
tagStore[i].set = 0;
tagStore[i].data = &dataStore[data_index];
data_index += blkSize;
}
freelist = primaryBound;
}
IIC::~IIC()
{
delete [] dataReferenceCount;
delete [] dataStore;
delete [] tagStore;
delete [] sets;
}
/* register cache stats */
void
IIC::regStats(const string &name)
{
using namespace Stats;
BaseTags::regStats(name);
hitHashDepth.init(0, 20, 1);
missHashDepth.init(0, 20, 1);
setAccess.init(0, hashSets, 1);
/** IIC Statistics */
hitHashDepth
.name(name + ".hit_hash_depth_dist")
.desc("Dist. of Hash lookup depths")
.flags(pdf)
;
missHashDepth
.name(name + ".miss_hash_depth_dist")
.desc("Dist. of Hash lookup depths")
.flags(pdf)
;
repl->regStatsWithSuffix(name);
if (PROFILE_IIC)
setAccess
.name(name + ".set_access_dist")
.desc("Dist. of Accesses across sets")
.flags(pdf)
;
missDepthTotal
.name(name + ".miss_depth_total")
.desc("Total of miss depths")
;
hashMiss
.name(name + ".hash_miss")
.desc("Total of misses in hash table")
;
hitDepthTotal
.name(name + ".hit_depth_total")
.desc("Total of hit depths")
;
hashHit
.name(name + ".hash_hit")
.desc("Total of hites in hash table")
;
}
IICTag*
IIC::accessBlock(Addr addr, int &lat, int context_src)
{
Addr tag = extractTag(addr);
unsigned set = hash(addr);
int set_lat;
unsigned long chain_ptr = tagNull;
if (PROFILE_IIC)
setAccess.sample(set);
IICTag *tag_ptr = sets[set].findTag(tag, chain_ptr);
set_lat = 1;
if (tag_ptr == NULL && chain_ptr != tagNull) {
int secondary_depth;
tag_ptr = secondaryChain(tag, chain_ptr, &secondary_depth);
set_lat += secondary_depth;
// set depth for statistics fix this later!!! egh
sets[set].depth = set_lat;
if (tag_ptr != NULL) {
/* need to move tag into primary table */
// need to preserve chain: fix this egh
sets[set].tags[assoc-1]->chain_ptr = tag_ptr->chain_ptr;
tagSwap(tag_ptr - tagStore, sets[set].tags[assoc-1] - tagStore);
tag_ptr = sets[set].findTag(tag, chain_ptr);
assert(tag_ptr!=NULL);
}
}
set_lat = set_lat * hashDelay + hitLatency;
if (tag_ptr != NULL) {
// IIC replacement: if this is not the first element of
// list, reorder
sets[set].moveToHead(tag_ptr);
hitHashDepth.sample(sets[set].depth);
hashHit++;
hitDepthTotal += sets[set].depth;
tag_ptr->status |= BlkReferenced;
lat = set_lat;
if (tag_ptr->whenReady > curTick() && tag_ptr->whenReady - curTick() > set_lat) {
lat = tag_ptr->whenReady - curTick();
}
tag_ptr->refCount += 1;
}
else {
// fall through: cache block not found, not a hit...
missHashDepth.sample(sets[set].depth);
hashMiss++;
missDepthTotal += sets[set].depth;
lat = set_lat;
}
return tag_ptr;
}
IICTag*
IIC::findBlock(Addr addr) const
{
Addr tag = extractTag(addr);
unsigned set = hash(addr);
unsigned long chain_ptr = tagNull;
IICTag *tag_ptr = sets[set].findTag(tag, chain_ptr);
if (tag_ptr == NULL && chain_ptr != tagNull) {
int secondary_depth;
tag_ptr = secondaryChain(tag, chain_ptr, &secondary_depth);
}
return tag_ptr;
}
IICTag*
IIC::findVictim(Addr addr, PacketList &writebacks)
{
DPRINTF(IIC, "Finding Replacement for %x\n", addr);
unsigned set = hash(addr);
IICTag *tag_ptr;
unsigned long *tmp_data = new unsigned long[numSub];
// Get a enough subblocks for a full cache line
for (unsigned i = 0; i < numSub; ++i){
tmp_data[i] = getFreeDataBlock(writebacks);
assert(dataReferenceCount[tmp_data[i]]==0);
}
tag_ptr = getFreeTag(set, writebacks);
tag_ptr->set = set;
for (unsigned i = 0; i < numSub; ++i) {
tag_ptr->data_ptr[i] = tmp_data[i];
dataReferenceCount[tag_ptr->data_ptr[i]]++;
}
tag_ptr->numData = numSub;
assert(tag_ptr - tagStore < primaryBound); // make sure it is in primary
tag_ptr->chain_ptr = tagNull;
sets[set].moveToHead(tag_ptr);
delete [] tmp_data;
list<unsigned long> tag_indexes;
repl->doAdvance(tag_indexes);
/*
while (!tag_indexes.empty()) {
if (!tagStore[tag_indexes.front()].isCompressed()) {
compress_blocks.push_back(&tagStore[tag_indexes.front()]);
}
tag_indexes.pop_front();
}
*/
tag_ptr->re = (void*)repl->add(tag_ptr-tagStore);
return tag_ptr;
}
void
IIC::insertBlock(Addr addr, BlkType* blk, int context_src)
{
}
void
IIC::freeReplacementBlock(PacketList & writebacks)
{
IICTag *tag_ptr;
unsigned long data_ptr;
/* consult replacement policy */
tag_ptr = &tagStore[repl->getRepl()];
assert(tag_ptr->isValid());
DPRINTF(Cache, "Replacing %x in IIC: %s\n",
regenerateBlkAddr(tag_ptr->tag,0),
tag_ptr->isDirty() ? "writeback" : "clean");
/* write back replaced block data */
if (tag_ptr && (tag_ptr->isValid())) {
replacements[0]++;
totalRefs += tag_ptr->refCount;
++sampledRefs;
tag_ptr->refCount = 0;
if (tag_ptr->isDirty()) {
/* PacketPtr writeback =
buildWritebackReq(regenerateBlkAddr(tag_ptr->tag, 0),
tag_ptr->req->asid, tag_ptr->xc, blkSize,
tag_ptr->data,
tag_ptr->size);
*/
Request *writebackReq = new Request(regenerateBlkAddr(tag_ptr->tag, 0),
blkSize, 0);
PacketPtr writeback = new Packet(writebackReq, MemCmd::Writeback,
-1);
writeback->allocate();
memcpy(writeback->getPtr<uint8_t>(), tag_ptr->data, blkSize);
writebacks.push_back(writeback);
}
}
// free the data blocks
for (int i = 0; i < tag_ptr->numData; ++i) {
data_ptr = tag_ptr->data_ptr[i];
assert(dataReferenceCount[data_ptr]>0);
if (--dataReferenceCount[data_ptr] == 0) {
freeDataBlock(data_ptr);
}
}
freeTag(tag_ptr);
}
unsigned long
IIC::getFreeDataBlock(PacketList & writebacks)
{
unsigned long data_ptr;
/* find data block */
while (blkFreelist.empty()) {
freeReplacementBlock(writebacks);
}
data_ptr = blkFreelist.front();
blkFreelist.pop_front();
DPRINTF(IICMore,"Found free data at %d\n",data_ptr);
return data_ptr;
}
IICTag*
IIC::getFreeTag(int set, PacketList & writebacks)
{
unsigned long tag_index;
IICTag *tag_ptr;
// Add new tag
tag_ptr = sets[set].findFree();
// if no free in primary, and secondary exists
if (!tag_ptr && numSecondary) {
// need to spill a tag into secondary storage
while (freelist == tagNull) {
// get replacements until one is in secondary
freeReplacementBlock(writebacks);
}
tag_index = freelist;
freelist = tagStore[freelist].chain_ptr;
freeSecond--;
assert(tag_index != tagNull);
tagSwap(tag_index, sets[set].tags[assoc-1] - tagStore);
tagStore[tag_index].chain_ptr = sets[set].chain_ptr;
sets[set].chain_ptr = tag_index;
tag_ptr = sets[set].tags[assoc-1];
}
DPRINTF(IICMore,"Found free tag at %d\n",tag_ptr - tagStore);
tagsInUse++;
if (!warmedUp && tagsInUse.value() >= warmupBound) {
warmedUp = true;
warmupCycle = curTick();
}
return tag_ptr;
}
void
IIC::freeTag(IICTag *tag_ptr)
{
unsigned long tag_index, tmp_index;
// Fix tag_ptr
if (tag_ptr) {
// we have a tag to clear
DPRINTF(IICMore,"Freeing Tag for %x\n",
regenerateBlkAddr(tag_ptr->tag,0));
tagsInUse--;
tag_ptr->status = 0;
tag_ptr->numData = 0;
tag_ptr->re = NULL;
tag_index = tag_ptr - tagStore;
if (tag_index >= primaryBound) {
// tag_ptr points to secondary store
assert(tag_index < tagNull); // remove this?? egh
if (tag_ptr->chain_ptr == tagNull) {
// need to fix chain list
unsigned tmp_set = hash(tag_ptr->tag << tagShift);
if (sets[tmp_set].chain_ptr == tag_index) {
sets[tmp_set].chain_ptr = tagNull;
} else {
tmp_index = sets[tmp_set].chain_ptr;
while (tmp_index != tagNull
&& tagStore[tmp_index].chain_ptr != tag_index) {
tmp_index = tagStore[tmp_index].chain_ptr;
}
assert(tmp_index != tagNull);
tagStore[tmp_index].chain_ptr = tagNull;
}
tag_ptr->chain_ptr = freelist;
freelist = tag_index;
freeSecond++;
} else {
// copy next chained entry to this tag location
tmp_index = tag_ptr->chain_ptr;
tagSwap(tmp_index, tag_index);
tagStore[tmp_index].chain_ptr = freelist;
freelist = tmp_index;
freeSecond++;
}
} else {
// tag_ptr in primary hash table
assert(tag_index < primaryBound);
tag_ptr->status = 0;
unsigned tmp_set = hash(tag_ptr->tag << tagShift);
if (sets[tmp_set].chain_ptr != tagNull) { // collapse chain
tmp_index = sets[tmp_set].chain_ptr;
tagSwap(tag_index, tmp_index);
tagStore[tmp_index].chain_ptr = freelist;
freelist = tmp_index;
freeSecond++;
sets[tmp_set].chain_ptr = tag_ptr->chain_ptr;
sets[tmp_set].moveToTail(tag_ptr);
}
}
}
}
void
IIC::freeDataBlock(unsigned long data_ptr)
{
assert(dataReferenceCount[data_ptr] == 0);
DPRINTF(IICMore, "Freeing data at %d\n", data_ptr);
blkFreelist.push_front(data_ptr);
}
/** Use a simple modulo hash. */
#define SIMPLE_HASH 0
unsigned
IIC::hash(Addr addr) const {
#if SIMPLE_HASH
return extractTag(addr) % iic_hash_size;
#else
Addr tag, mask, x, y;
tag = extractTag(addr);
mask = hashSets-1; /* assumes iic_hash_size is a power of 2 */
x = tag & mask;
y = (tag >> (int)(::log((double)hashSets)/::log((double)2))) & mask;
assert (x < hashSets && y < hashSets);
return x ^ y;
#endif
}
void
IICSet::moveToHead(IICTag *tag)
{
if (tags[0] == tag)
return;
// write 'next' block into blks[i], moving up from MRU toward LRU
// until we overwrite the block we moved to head.
// start by setting up to write 'blk' into blks[0]
int i = 0;
IICTag *next = tag;
do {
assert(i < assoc);
// swap blks[i] and next
IICTag *tmp = tags[i];
tags[i] = next;
next = tmp;
++i;
} while (next != tag);
}
void
IICSet::moveToTail(IICTag *tag)
{
if (tags[assoc-1] == tag)
return;
// write 'next' block into blks[i], moving up from MRU toward LRU
// until we overwrite the block we moved to head.
// start by setting up to write 'blk' into blks[0]
int i = assoc - 1;
IICTag *next = tag;
do {
assert(i >= 0);
// swap blks[i] and next
IICTag *tmp = tags[i];
tags[i] = next;
next = tmp;
--i;
} while (next != tag);
}
void
IIC::tagSwap(unsigned long index1, unsigned long index2)
{
DPRINTF(IIC,"Swapping tag[%d]=%x for tag[%d]=%x\n",index1,
tagStore[index1].tag<<tagShift, index2,
tagStore[index2].tag<<tagShift);
IICTag tmp_tag;
tmp_tag = tagStore[index1];
tagStore[index1] = tagStore[index2];
tagStore[index2] = tmp_tag;
if (tagStore[index1].isValid())
repl->fixTag(tagStore[index1].re, index2, index1);
if (tagStore[index2].isValid())
repl->fixTag(tagStore[index2].re, index1, index2);
}
IICTag *
IIC::secondaryChain(Addr tag, unsigned long chain_ptr,
int *_depth) const
{
int depth = 0;
while (chain_ptr != tagNull) {
DPRINTF(IIC,"Searching secondary at %d for %x\n", chain_ptr,
tag<<tagShift);
if (tagStore[chain_ptr].tag == tag &&
(tagStore[chain_ptr].isValid())) {
*_depth = depth;
return &tagStore[chain_ptr];
}
depth++;
chain_ptr = tagStore[chain_ptr].chain_ptr;
}
*_depth = depth;
return NULL;
}
void
IIC::invalidateBlk(IIC::BlkType *tag_ptr)
{
if (tag_ptr) {
for (int i = 0; i < tag_ptr->numData; ++i) {
dataReferenceCount[tag_ptr->data_ptr[i]]--;
if (dataReferenceCount[tag_ptr->data_ptr[i]] == 0) {
freeDataBlock(tag_ptr->data_ptr[i]);
}
}
repl->removeEntry(tag_ptr->re);
freeTag(tag_ptr);
}
}
void
IIC::clearLocks()
{
for (int i = 0; i < numTags; i++){
tagStore[i].clearLoadLocks();
}
}
void
IIC::cleanupRefs()
{
for (unsigned i = 0; i < numTags; ++i) {
if (tagStore[i].isValid()) {
totalRefs += tagStore[i].refCount;
++sampledRefs;
}
}
}