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Clean up some of vincent's code and commit it

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Makes page table cache scheme actually work

src/mem/page_table.cc:
src/mem/page_table.hh:
    fix caching scheme to actually work and improve performance

--HG--
extra : convert_revision : 443a8d8acbee540b26affcfdfbf107b8e735d1bd
This commit is contained in:
Ali Saidi 2007-06-05 01:03:35 -04:00
parent 48133a0f04
commit 85986e9dff
2 changed files with 24 additions and 14 deletions
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22
src/mem/page_table.cc
View file

@ -90,8 +90,6 @@ PageTable::page_check(Addr addr, int64_t size) const
}
void
PageTable::allocate(Addr vaddr, int64_t size)
{
@ -109,12 +107,7 @@ PageTable::allocate(Addr vaddr, int64_t size)
}
pTable[vaddr] = system->new_page();
pTableCache[2].paddr = pTableCache[1].paddr;
pTableCache[2].vaddr = pTableCache[1].vaddr;
pTableCache[1].paddr = pTableCache[0].paddr;
pTableCache[1].vaddr = pTableCache[0].vaddr;
pTableCache[0].paddr = pTable[vaddr];
pTableCache[0].vaddr = vaddr;
updateCache(vaddr, pTable[vaddr]);
}
}
@ -126,16 +119,16 @@ PageTable::translate(Addr vaddr, Addr &paddr)
Addr page_addr = pageAlign(vaddr);
paddr = 0;
if (pTableCache[0].vaddr == vaddr) {
paddr = pTableCache[0].paddr;
if (pTableCache[0].vaddr == page_addr) {
paddr = pTableCache[0].paddr + pageOffset(vaddr);
return true;
}
if (pTableCache[1].vaddr == vaddr) {
paddr = pTableCache[1].paddr;
if (pTableCache[1].vaddr == page_addr) {
paddr = pTableCache[1].paddr + pageOffset(vaddr);
return true;
}
if (pTableCache[2].vaddr == vaddr) {
paddr = pTableCache[2].paddr;
if (pTableCache[2].vaddr == page_addr) {
paddr = pTableCache[2].paddr + pageOffset(vaddr);
return true;
}
@ -145,6 +138,7 @@ PageTable::translate(Addr vaddr, Addr &paddr)
return false;
}
updateCache(page_addr, iter->second);
paddr = iter->second + pageOffset(vaddr);
return true;
}

16
src/mem/page_table.hh
View file

@ -95,6 +95,22 @@ class PageTable
*/
Fault translate(RequestPtr &req);
/**
* Update the page table cache.
* @param vaddr virtual address (page aligned) to check
* @param paddr physical address (page aligned) to return
*/
inline void updateCache(Addr vaddr, Addr paddr)
{
pTableCache[2].paddr = pTableCache[1].paddr;
pTableCache[2].vaddr = pTableCache[1].vaddr;
pTableCache[1].paddr = pTableCache[0].paddr;
pTableCache[1].vaddr = pTableCache[0].vaddr;
pTableCache[0].paddr = paddr;
pTableCache[0].vaddr = vaddr;
}
void serialize(std::ostream &os);
void unserialize(Checkpoint *cp, const std::string &section);
};