public void recv_wb_req(Req req)
{
//stats
Stat.procs[pid].write_req_served.collect();
Stat.procs[pid].write_avg_latency.collect(req.Latency);
//destroy req
RequestPool.Enpool(req);
}
// Callback function when a memory request is complete. This retires instructions or inserts data back into caches.
public void recv_req(Req req)
{
// Install the rest of the words in the cacheline
bool cw_contains_write = false;
//stats
if (!req.CpyGenReq)
{
Stat.procs[pid].read_req_served.collect();
Stat.procs[pid].read_avg_latency.collect(req.Latency);
}
// Handles the read write request
if (req.RdWr)
{
Dbg.Assert(read_write_q.Contains(req.BlockAddr));
read_write_q.Remove(req.BlockAddr);
}
//free up instruction window and mshr
bool contains_write = inst_wnd.set_ready(req.BlockAddr);
contains_write |= cw_contains_write;
mshr.RemoveAll(x => x == req.BlockAddr);
Req wb_req = null;
// Install cachelines and handle dirty block evictions
if (Config.proc.cache_enabled)
{
cache_handler(req, contains_write);
}
else
{
Dbg.AssertPrint(!contains_write, "Inst window contains write reqeusts.");
// Writeback based on the cache filtered traces
wb_req = req.WbReq;
if (wb_req != null)
{
bool wb_merge = wb_q.Exists(x => x.BlockAddr == wb_req.BlockAddr);
if (!wb_merge)
{
addWB(wb_req);
}
else
{
RequestPool.Enpool(wb_req);
}
}
}
//destory req
RequestPool.Enpool(req);
out_read_req--;
}
// Null upper_c means c is a L1 cache, otherwise L2
public void service_cache_hit_queue(Cache c, Cache upper_c = null)
{
LinkedList <Req> hit_queue = c.get_hit_queue(pid);
while (hit_queue.Count != 0)
{
Req req = hit_queue.First.Value;
int hit_pid = req.Pid;
Dbg.Assert(hit_pid == pid);
if ((ulong)req.TsDeparture <= cycles)
{
// Hit in L2 and move L2 $line to L1
if (upper_c != null)
{
Cache l1c = upper_c;
Dbg.AssertPrint(!l1c.in_cache(req.BlockAddr),
"$line from an L2 hit shouldn't be in L1.");
ulong l1c_wb_addr = l1c.cache_add(req.BlockAddr, req.Type, hit_pid);
// Dirty $line eviction from L1, check L2 first.
if (l1c_wb_addr != NULL_ADDRESS)
{
// Miss in L2
if (!c.is_cache_hit(l1c_wb_addr, ReqType.WRITE))
{
// Another potential wb from L2
ulong l2c_wb_addr = c.cache_add(l1c_wb_addr, ReqType.WRITE, hit_pid);
if (l2c_wb_addr != NULL_ADDRESS)
{
gen_cache_wb_req(l2c_wb_addr);
}
}
}
Stat.procs[pid].l2_cache_hit_avg_latency.collect((int)(cycles - (ulong)req.TsArrival));
}
else
{
Stat.procs[pid].l1_cache_hit_avg_latency.collect((int)(cycles - (ulong)req.TsArrival));
}
// Simply hit in L1
hit_queue.RemoveFirst();
inst_wnd.set_ready(req.BlockAddr);
RequestPool.Enpool(req);
}
else
{
return;
}
}
}
public void recv_copy_req(Req req)
{
//stats
Stat.procs[pid].copy_req_served.collect();
Stat.procs[pid].copy_avg_latency.collect(req.Latency);
//free up instruction window and mshr
bool contains_write = inst_wnd.set_ready(req.BlockAddr, true);
mshr.RemoveAll(x => x == req.BlockAddr);
Dbg.AssertPrint(!contains_write, "Inst window contains write reqeusts. COPY is not supported in cache mode.");
Dbg.Assert(req.WbReq == null);
//destory req
RequestPool.Enpool(req);
}
// Generate a new writeback request to memory from L2 dirty block eviction
public void gen_cache_wb_req(ulong wb_addr)
{
Req wb_req = RequestPool.Depool();
wb_req.Set(pid, ReqType.WRITE, wb_addr);
bool wb_merge = wb_q.Exists(x => x.BlockAddr == wb_req.BlockAddr);
if (!wb_merge)
{
addWB(wb_req);
}
else
{
RequestPool.Enpool(wb_req);
}
}
public void issue_insts(bool issued_rd_req)
{
//issue instructions
for (int i = 0; i < Config.proc.ipc; i++)
{
Dbg.Assert(curr_rd_req != null);
if (curr_rd_req == null)
{
return;
}
// Stats
if (inst_wnd.is_full())
{
if (i == 0)
{
Stat.procs[pid].stall_inst_wnd.collect();
consec_stalled++;
}
return;
}
//cpu instructions
if (curr_cpu_inst_cnt > 0)
{
curr_cpu_inst_cnt--;
inst_wnd.add(0, false, true, 0); // word oblivious
continue;
}
//only one memory instruction can be issued per cycle
if (issued_rd_req)
{
return;
}
// Ideal memory
if (Config.proc.ideal_memory)
{
Dbg.AssertPrint(!Config.proc.cache_enabled, "Cache is not supported in ideal memory mode.");
if (curr_rd_req.WbReq != null)
{
RequestPool.Enpool(curr_rd_req.WbReq);
}
RequestPool.Enpool(curr_rd_req);
curr_rd_req = get_req();
return;
}
// Need to mark if an instruction is a write on cache mode or COPY for a copy instruction
inst_wnd.add(curr_rd_req.BlockAddr, true, false, curr_rd_req.WordOffset,
(curr_rd_req.Type == ReqType.WRITE) && Config.proc.cache_enabled, curr_rd_req.Type == ReqType.COPY);
// check if true miss --
bool false_miss = inst_wnd.is_duplicate(curr_rd_req.BlockAddr);
// COPY is a special instruction, so we don't care about if its address is a duplicate of other instructions
if (false_miss && Config.proc.issue_on_dup_req && curr_rd_req.Type != ReqType.COPY)
{
Dbg.Assert(curr_rd_req.WbReq == null);
RequestPool.Enpool(curr_rd_req);
curr_rd_req = get_req();
continue;
}
// STATS
collect_inst_stats();
// Caches
if (Config.proc.cache_enabled && curr_rd_req.Type != ReqType.COPY)
{
// Check for in-flight rd_wr_q.
// Since write is duplicate, drop it....
bool in_rd_wr_q = read_write_q.Contains(curr_rd_req.BlockAddr);
// L1
if (l1c.is_cache_hit(curr_rd_req.BlockAddr, curr_rd_req.Type))
{
Dbg.AssertPrint(!in_rd_wr_q, "Both in rd_wr_q and L1 cache baddr=" + curr_rd_req.BlockAddr);
// HIT: Add to l1 cache hit queue to model the latency
add_cache_hit_queue(l1c, curr_rd_req);
curr_rd_req = get_req();
issued_rd_req = true;
continue;
}
// L2
if (l2c.is_cache_hit(curr_rd_req.BlockAddr, curr_rd_req.Type))
{
Dbg.Assert(!in_rd_wr_q);
// HIT: Add to l2 cache hit queue to model the latency,
// add to l1 cache after it is served from the hit queue
add_cache_hit_queue(l2c, curr_rd_req);
curr_rd_req = get_req();
issued_rd_req = true;
continue;
}
if (in_rd_wr_q)
{
if (curr_rd_req.Type == ReqType.WRITE)
{
inst_wnd.set_ready(curr_rd_req.BlockAddr);
}
RequestPool.Enpool(curr_rd_req);
curr_rd_req = get_req();
issued_rd_req = true;
continue;
}
// If write allocate -- 1. need to make sure the following read request
// detects this reading request generated from write
// 2. don't stall the instruction window
// Make it into a read request, then on receving the
// request, put them into the cache and mark them dirty.
if (curr_rd_req.Type == ReqType.WRITE)
{
convert_to_read_write(ref curr_rd_req);
}
}
// **** GO TO MEMORY ****
//try mshr
bool mshr_ok = insert_mshr(curr_rd_req);
if (!mshr_ok)
{
mshr_retry = true;
return;
}
//try memory controller
bool mctrl_ok = insert_mctrl(curr_rd_req);
if (!mctrl_ok)
{
mctrl_retry = true;
return;
}
//issued memory request
issued_rd_req = true;
//get new read request
curr_rd_req = get_req();
}
}
