[llvm-mca] Use a vector to store ResourceState objects in the ResourceManager.
We don't need to use a map to store ResourceState objects. The number of
processor resources is known statically from the scheduling model. We can
therefore use a vector, and reserve a slot for each processor resource that we
want to simulate.
Every time the ResourceManager queries the ResourceState vector, the index to
the vector of ResourceState objects can be easily computed from the processor
resource mask.
This drastically reduces the time complexity of method ResourceManager::use() and
method ResourceManager::release(). This patch gives an average speedup of 12%.
llvm-svn: 338702
diff --git a/llvm/tools/llvm-mca/Scheduler.h b/llvm/tools/llvm-mca/Scheduler.h
index 428fbc0..b0d2dbc 100644
--- a/llvm/tools/llvm-mca/Scheduler.h
+++ b/llvm/tools/llvm-mca/Scheduler.h
@@ -274,7 +274,7 @@
class ResourceManager {
// The resource manager owns all the ResourceState.
using UniqueResourceState = std::unique_ptr<ResourceState>;
- llvm::SmallDenseMap<uint64_t, UniqueResourceState> Resources;
+ std::vector<UniqueResourceState> Resources;
// Keeps track of which resources are busy, and how many cycles are left
// before those become usable again.
@@ -283,46 +283,16 @@
// A table to map processor resource IDs to processor resource masks.
llvm::SmallVector<uint64_t, 8> ProcResID2Mask;
- // Adds a new resource state in Resources, as well as a new descriptor in
- // ResourceDescriptor.
- void addResource(const llvm::MCProcResourceDesc &Desc, unsigned Index,
- uint64_t Mask);
-
// Populate resource descriptors.
void initialize(const llvm::MCSchedModel &SM);
// Returns the actual resource unit that will be used.
ResourceRef selectPipe(uint64_t ResourceID);
- void use(ResourceRef RR);
- void release(ResourceRef RR);
+ void use(const ResourceRef &RR);
+ void release(const ResourceRef &RR);
- unsigned getNumUnits(uint64_t ResourceID) const {
- assert(Resources.find(ResourceID) != Resources.end());
- return Resources.find(ResourceID)->getSecond()->getNumUnits();
- }
-
- // Reserve a specific Resource kind.
- void reserveBuffer(uint64_t ResourceID) {
- assert(isBufferAvailable(ResourceID) ==
- ResourceStateEvent::RS_BUFFER_AVAILABLE);
- ResourceState &Resource = *Resources[ResourceID];
- Resource.reserveBuffer();
- }
-
- void releaseBuffer(uint64_t ResourceID) {
- Resources[ResourceID]->releaseBuffer();
- }
-
- ResourceStateEvent isBufferAvailable(uint64_t ResourceID) const {
- const ResourceState &Resource = *Resources.find(ResourceID)->second;
- return Resource.isBufferAvailable();
- }
-
- bool isReady(uint64_t ResourceID, unsigned NumUnits) const {
- const ResourceState &Resource = *Resources.find(ResourceID)->second;
- return Resource.isReady(NumUnits);
- }
+ unsigned getNumUnits(uint64_t ResourceID) const;
public:
ResourceManager(const llvm::MCSchedModel &SM)
@@ -335,9 +305,7 @@
ResourceStateEvent canBeDispatched(llvm::ArrayRef<uint64_t> Buffers) const;
// Return the processor resource identifier associated to this Mask.
- unsigned resolveResourceMask(uint64_t Mask) const {
- return Resources.find(Mask)->second->getProcResourceID();
- }
+ unsigned resolveResourceMask(uint64_t Mask) const;
// Consume a slot in every buffered resource from array 'Buffers'. Resource
// units that are dispatch hazards (i.e. BufferSize=0) are marked as reserved.
@@ -346,16 +314,12 @@
// Release buffer entries previously allocated by method reserveBuffers.
void releaseBuffers(llvm::ArrayRef<uint64_t> Buffers);
- void reserveResource(uint64_t ResourceID) {
- ResourceState &Resource = *Resources[ResourceID];
- assert(!Resource.isReserved());
- Resource.setReserved();
- }
+ // Reserve a processor resource. A reserved resource is not available for
+ // instruction issue until it is released.
+ void reserveResource(uint64_t ResourceID);
- void releaseResource(uint64_t ResourceID) {
- ResourceState &Resource = *Resources[ResourceID];
- Resource.clearReserved();
- }
+ // Release a previously reserved processor resource.
+ void releaseResource(uint64_t ResourceID);
// Returns true if all resources are in-order, and there is at least one
// resource which is a dispatch hazard (BufferSize = 0).
@@ -371,8 +335,8 @@
#ifndef NDEBUG
void dump() const {
- for (const std::pair<uint64_t, UniqueResourceState> &Resource : Resources)
- Resource.second->dump();
+ for (const UniqueResourceState &Resource : Resources)
+ Resource->dump();
}
#endif
}; // namespace mca