diff options
Diffstat (limited to 'riscv/cachesim.cc')
-rw-r--r-- | riscv/cachesim.cc | 94 |
1 files changed, 71 insertions, 23 deletions
diff --git a/riscv/cachesim.cc b/riscv/cachesim.cc index d029c29..cd33ca1 100644 --- a/riscv/cachesim.cc +++ b/riscv/cachesim.cc @@ -1,4 +1,5 @@ #include "cachesim.h" +#include "common.h" #include <cstdlib> #include <iostream> #include <iomanip> @@ -18,19 +19,20 @@ static void help() exit(1); } -cache_sim_t::cache_sim_t(const char* config, const char* _name) - : name(_name) +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(); - sets = atoi(std::string(config, wp).c_str()); - ways = atoi(std::string(wp, bp).c_str()); - linesz = atoi(bp); + 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); - init(); + 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() @@ -96,34 +98,80 @@ void cache_sim_t::print_stats() 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; - size_t idx = (addr >> idx_shift) & (sets-1); - size_t tag = (addr >> idx_shift) | VALID; - size_t* set_tags = &tags[idx*ways]; - - for(size_t i = 0; i < ways; i++) + uint64_t* hit_way = check_tag(addr); + if (likely(hit_way != NULL)) { - if(tag == (set_tags[i] & ~DIRTY)) // hit - { - if(store) - set_tags[i] |= DIRTY; - return; - } + if (store) + *hit_way |= DIRTY; + return; } store ? write_misses++ : read_misses++; - size_t way = lfsr.next() % ways; - if((set_tags[way] & (VALID | DIRTY)) == (VALID | DIRTY)) + uint64_t victim = victimize(addr); + + if ((victim & (VALID | DIRTY)) == (VALID | DIRTY)) { - uint64_t dirty_addr = (set_tags[way] & ~(VALID | DIRTY)) << idx_shift; - if (miss_handler) miss_handler->access(dirty_addr, linesz, true); + 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); - set_tags[way] = tag | (store ? DIRTY : 0); + + 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; } |