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// See LICENSE for license details.
#include "cachesim.h"
#include "common.h"
#include <cstdlib>
#include <iostream>
#include <iomanip>
cache_sim_t::cache_sim_t(size_t _sets, size_t _ways, size_t _linesz, const char* _name)
: sets(_sets), ways(_ways), linesz(_linesz), name(_name), log(false)
{
init();
}
static void help()
{
std::cerr << "Cache configurations must be of the form" << std::endl;
std::cerr << " sets:ways:blocksize" << std::endl;
std::cerr << "where sets, ways, and blocksize are positive integers, with" << std::endl;
std::cerr << "sets and blocksize both powers of two and blocksize at least 8." << std::endl;
exit(1);
}
cache_sim_t* cache_sim_t::construct(const char* config, const char* name)
{
const char* wp = strchr(config, ':');
if (!wp++) help();
const char* bp = strchr(wp, ':');
if (!bp++) help();
size_t sets = atoi(std::string(config, wp).c_str());
size_t ways = atoi(std::string(wp, bp).c_str());
size_t linesz = atoi(bp);
if (ways > 4 /* empirical */ && sets == 1)
return new fa_cache_sim_t(ways, linesz, name);
return new cache_sim_t(sets, ways, linesz, name);
}
void cache_sim_t::init()
{
if(sets == 0 || (sets & (sets-1)))
help();
if(linesz < 8 || (linesz & (linesz-1)))
help();
idx_shift = 0;
for (size_t x = linesz; x>1; x >>= 1)
idx_shift++;
tags = new uint64_t[sets*ways]();
read_accesses = 0;
read_misses = 0;
bytes_read = 0;
write_accesses = 0;
write_misses = 0;
bytes_written = 0;
writebacks = 0;
miss_handler = NULL;
}
cache_sim_t::cache_sim_t(const cache_sim_t& rhs)
: sets(rhs.sets), ways(rhs.ways), linesz(rhs.linesz),
idx_shift(rhs.idx_shift), name(rhs.name), log(false)
{
tags = new uint64_t[sets*ways];
memcpy(tags, rhs.tags, sets*ways*sizeof(uint64_t));
}
cache_sim_t::~cache_sim_t()
{
print_stats();
delete [] tags;
}
void cache_sim_t::print_stats()
{
if(read_accesses + write_accesses == 0)
return;
float mr = 100.0f*(read_misses+write_misses)/(read_accesses+write_accesses);
std::cout << std::setprecision(3) << std::fixed;
std::cout << name << " ";
std::cout << "Bytes Read: " << bytes_read << std::endl;
std::cout << name << " ";
std::cout << "Bytes Written: " << bytes_written << std::endl;
std::cout << name << " ";
std::cout << "Read Accesses: " << read_accesses << std::endl;
std::cout << name << " ";
std::cout << "Write Accesses: " << write_accesses << std::endl;
std::cout << name << " ";
std::cout << "Read Misses: " << read_misses << std::endl;
std::cout << name << " ";
std::cout << "Write Misses: " << write_misses << std::endl;
std::cout << name << " ";
std::cout << "Writebacks: " << writebacks << std::endl;
std::cout << name << " ";
std::cout << "Miss Rate: " << mr << '%' << std::endl;
}
uint64_t* cache_sim_t::check_tag(uint64_t addr)
{
size_t idx = (addr >> idx_shift) & (sets-1);
size_t tag = (addr >> idx_shift) | VALID;
for (size_t i = 0; i < ways; i++)
if (tag == (tags[idx*ways + i] & ~DIRTY))
return &tags[idx*ways + i];
return NULL;
}
uint64_t cache_sim_t::victimize(uint64_t addr)
{
size_t idx = (addr >> idx_shift) & (sets-1);
size_t way = lfsr.next() % ways;
uint64_t victim = tags[idx*ways + way];
tags[idx*ways + way] = (addr >> idx_shift) | VALID;
return victim;
}
void cache_sim_t::access(uint64_t addr, size_t bytes, bool store)
{
store ? write_accesses++ : read_accesses++;
(store ? bytes_written : bytes_read) += bytes;
uint64_t* hit_way = check_tag(addr);
if (likely(hit_way != NULL))
{
if (store)
*hit_way |= DIRTY;
return;
}
store ? write_misses++ : read_misses++;
if (log)
{
std::cerr << name << " "
<< (store ? "write" : "read") << " miss 0x"
<< std::hex << addr << std::endl;
}
uint64_t victim = victimize(addr);
if ((victim & (VALID | DIRTY)) == (VALID | DIRTY))
{
uint64_t dirty_addr = (victim & ~(VALID | DIRTY)) << idx_shift;
if (miss_handler)
miss_handler->access(dirty_addr, linesz, true);
writebacks++;
}
if (miss_handler)
miss_handler->access(addr & ~(linesz-1), linesz, false);
if (store)
*check_tag(addr) |= DIRTY;
}
fa_cache_sim_t::fa_cache_sim_t(size_t ways, size_t linesz, const char* name)
: cache_sim_t(1, ways, linesz, name)
{
}
uint64_t* fa_cache_sim_t::check_tag(uint64_t addr)
{
auto it = tags.find(addr >> idx_shift);
return it == tags.end() ? NULL : &it->second;
}
uint64_t fa_cache_sim_t::victimize(uint64_t addr)
{
uint64_t old_tag = 0;
if (tags.size() == ways)
{
auto it = tags.begin();
std::advance(it, lfsr.next() % ways);
old_tag = it->second;
tags.erase(it);
}
tags[addr >> idx_shift] = (addr >> idx_shift) | VALID;
return old_tag;
}
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