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AtomicSimpleCPU: Separate data stalls from instruction stalls.

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Separate simulation of icache stalls and dat stalls.
This commit is contained in:
Nathan Binkert 2008-06-18 10:15:21 -07:00
parent f24f2c57b6
commit 67a33eed40
3 changed files with 31 additions and 17 deletions
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3
src/cpu/simple/AtomicSimpleCPU.py
View file

@ -33,7 +33,8 @@ from BaseCPU import BaseCPU
class AtomicSimpleCPU(BaseCPU): class AtomicSimpleCPU(BaseCPU):
type = 'AtomicSimpleCPU' type = 'AtomicSimpleCPU'
width = Param.Int(1, "CPU width") width = Param.Int(1, "CPU width")
simulate_stalls = Param.Bool(False, "Simulate cache stall cycles") simulate_data_stalls = Param.Bool(False, "Simulate dcache stall cycles")
simulate_inst_stalls = Param.Bool(False, "Simulate icache stall cycles")
function_trace = Param.Bool(False, "Enable function trace") function_trace = Param.Bool(False, "Enable function trace")
function_trace_start = Param.Tick(0, "Cycle to start function trace") function_trace_start = Param.Tick(0, "Cycle to start function trace")
if build_env['FULL_SYSTEM']: if build_env['FULL_SYSTEM']:

39
src/cpu/simple/atomic.cc
View file

@ -153,8 +153,9 @@ AtomicSimpleCPU::DcachePort::setPeer(Port *port)
} }
AtomicSimpleCPU::AtomicSimpleCPU(Params *p) AtomicSimpleCPU::AtomicSimpleCPU(Params *p)
: BaseSimpleCPU(p), tickEvent(this), : BaseSimpleCPU(p), tickEvent(this), width(p->width),
width(p->width), simulate_stalls(p->simulate_stalls), simulate_data_stalls(p->simulate_data_stalls),
simulate_inst_stalls(p->simulate_inst_stalls),
icachePort(name() + "-iport", this), dcachePort(name() + "-iport", this), icachePort(name() + "-iport", this), dcachePort(name() + "-iport", this),
physmemPort(name() + "-iport", this), hasPhysMemPort(false) physmemPort(name() + "-iport", this), hasPhysMemPort(false)
{ {
@ -711,7 +712,7 @@ AtomicSimpleCPU::tick()
{ {
DPRINTF(SimpleCPU, "Tick\n"); DPRINTF(SimpleCPU, "Tick\n");
Tick latency = ticks(1); // instruction takes one cycle by default Tick latency = 0;
for (int i = 0; i < width; ++i) { for (int i = 0; i < width; ++i) {
numCycles++; numCycles++;
@ -769,16 +770,21 @@ AtomicSimpleCPU::tick()
curStaticInst->isFirstMicroop())) curStaticInst->isFirstMicroop()))
instCnt++; instCnt++;
if (simulate_stalls) { Tick stall_ticks = 0;
Tick icache_stall = if (simulate_inst_stalls && icache_access)
icache_access ? icache_latency - ticks(1) : 0; stall_ticks += icache_latency;
Tick dcache_stall =
dcache_access ? dcache_latency - ticks(1) : 0; if (simulate_data_stalls && dcache_access)
Tick stall_cycles = (icache_stall + dcache_stall) / ticks(1); stall_ticks += dcache_latency;
if (ticks(stall_cycles) < (icache_stall + dcache_stall))
latency += ticks(stall_cycles+1); if (stall_ticks) {
else Tick stall_cycles = stall_ticks / ticks(1);
latency += ticks(stall_cycles); Tick aligned_stall_ticks = ticks(stall_cycles);
if (aligned_stall_ticks < stall_ticks)
aligned_stall_ticks += 1;
latency += aligned_stall_ticks;
} }
} }
@ -786,6 +792,10 @@ AtomicSimpleCPU::tick()
advancePC(fault); advancePC(fault);
} }
// instruction takes at least one cycle
if (latency < ticks(1))
latency = ticks(1);
if (_status != Idle) if (_status != Idle)
tickEvent.schedule(curTick + latency); tickEvent.schedule(curTick + latency);
} }
@ -819,7 +829,8 @@ AtomicSimpleCPUParams::create()
params->functionTrace = function_trace; params->functionTrace = function_trace;
params->functionTraceStart = function_trace_start; params->functionTraceStart = function_trace_start;
params->width = width; params->width = width;
params->simulate_stalls = simulate_stalls; params->simulate_data_stalls = simulate_data_stalls;
params->simulate_inst_stalls = simulate_inst_stalls;
params->system = system; params->system = system;
params->cpu_id = cpu_id; params->cpu_id = cpu_id;
params->tracer = tracer; params->tracer = tracer;

6
src/cpu/simple/atomic.hh
View file

@ -39,7 +39,8 @@ class AtomicSimpleCPU : public BaseSimpleCPU
struct Params : public BaseSimpleCPU::Params { struct Params : public BaseSimpleCPU::Params {
int width; int width;
bool simulate_stalls; bool simulate_data_stalls;
bool simulate_inst_stalls;
}; };
AtomicSimpleCPU(Params *params); AtomicSimpleCPU(Params *params);
@ -74,7 +75,8 @@ class AtomicSimpleCPU : public BaseSimpleCPU
TickEvent tickEvent; TickEvent tickEvent;
const int width; const int width;
const bool simulate_stalls; const bool simulate_data_stalls;
const bool simulate_inst_stalls;
// main simulation loop (one cycle) // main simulation loop (one cycle)
void tick(); void tick();