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alpha: Implement a cache for recently used page table entries

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--HG--
extra : convert_revision : 1bb80d71fa91e500a68390e5dc17464ce7136fba
This commit is contained in:
Vincentius Robby 2007-08-04 14:25:35 -04:00
parent acac5580f2
commit 2898d76827
2 changed files with 31 additions and 11 deletions
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38
src/arch/alpha/tlb.cc
View file

@ -64,6 +64,7 @@ TLB::TLB(const string &name, int s)
{
table = new PTE[size];
memset(table, 0, sizeof(PTE[size]));
flushCache();
}
TLB::~TLB()
@ -79,18 +80,29 @@ TLB::lookup(Addr vpn, uint8_t asn) const
// assume not found...
PTE *retval = NULL;
PageTable::const_iterator i = lookupTable.find(vpn);
if (i != lookupTable.end()) {
while (i->first == vpn) {
int index = i->second;
PTE *pte = &table[index];
assert(pte->valid);
if (vpn == pte->tag && (pte->asma || pte->asn == asn)) {
retval = pte;
break;
}
if (PTECache[0] && vpn == PTECache[0]->tag &&
(PTECache[0]->asma || PTECache[0]->asn == asn))
retval = PTECache[0];
else if (PTECache[1] && vpn == PTECache[1]->tag &&
(PTECache[1]->asma || PTECache[1]->asn == asn))
retval = PTECache[1];
else if (PTECache[2] && vpn == PTECache[2]->tag &&
(PTECache[2]->asma || PTECache[2]->asn == asn))
retval = PTECache[2];
else {
PageTable::const_iterator i = lookupTable.find(vpn);
if (i != lookupTable.end()) {
while (i->first == vpn) {
int index = i->second;
PTE *pte = &table[index];
assert(pte->valid);
if (vpn == pte->tag && (pte->asma || pte->asn == asn)) {
retval = pte;
break;
}
++i;
++i;
}
}
}
@ -142,6 +154,7 @@ TLB::checkCacheability(RequestPtr &req)
void
TLB::insert(Addr addr, PTE &pte)
{
flushCache();
VAddr vaddr = addr;
if (table[nlu].valid) {
Addr oldvpn = table[nlu].tag;
@ -178,6 +191,7 @@ TLB::flushAll()
{
DPRINTF(TLB, "flushAll\n");
memset(table, 0, sizeof(PTE[size]));
flushCache();
lookupTable.clear();
nlu = 0;
}
@ -185,6 +199,7 @@ TLB::flushAll()
void
TLB::flushProcesses()
{
flushCache();
PageTable::iterator i = lookupTable.begin();
PageTable::iterator end = lookupTable.end();
while (i != end) {
@ -208,6 +223,7 @@ TLB::flushProcesses()
void
TLB::flushAddr(Addr addr, uint8_t asn)
{
flushCache();
VAddr vaddr = addr;
PageTable::iterator i = lookupTable.find(vaddr.vpn());

4
src/arch/alpha/tlb.hh
View file

@ -88,6 +88,10 @@ namespace AlphaISA
// Checkpointing
virtual void serialize(std::ostream &os);
virtual void unserialize(Checkpoint *cp, const std::string &section);
// Most recently used page table entries
PTE *PTECache[2];
inline void flushCache() { memset(PTECache, 0, 2 * sizeof(PTE*)); }
};
class ITB : public TLB