[llvm-mca] Move ResourceManager from Scheduler into its own file. NFC.
This time I should be preserving history of the ResourceManager changes.
llvm-svn: 340668
diff --git a/llvm/tools/llvm-mca/Scheduler.h b/llvm/tools/llvm-mca/Scheduler.h
index ed138fd..70f90c5 100644
--- a/llvm/tools/llvm-mca/Scheduler.h
+++ b/llvm/tools/llvm-mca/Scheduler.h
@@ -16,348 +16,13 @@
#define LLVM_TOOLS_LLVM_MCA_SCHEDULER_H
#include "HardwareUnit.h"
-#include "Instruction.h"
#include "LSUnit.h"
-#include "llvm/ADT/ArrayRef.h"
-#include "llvm/ADT/DenseMap.h"
+#include "ResourceManager.h"
#include "llvm/ADT/SmallVector.h"
-#include "llvm/MC/MCSubtargetInfo.h"
-#include <map>
+#include "llvm/MC/MCSchedule.h"
namespace mca {
-/// Used to notify the internal state of a processor resource.
-///
-/// A processor resource is available if it is not reserved, and there are
-/// available slots in the buffer. A processor resource is unavailable if it
-/// is either reserved, or the associated buffer is full. A processor resource
-/// with a buffer size of -1 is always available if it is not reserved.
-///
-/// Values of type ResourceStateEvent are returned by method
-/// ResourceState::isBufferAvailable(), which is used to query the internal
-/// state of a resource.
-///
-/// The naming convention for resource state events is:
-/// * Event names start with prefix RS_
-/// * Prefix RS_ is followed by a string describing the actual resource state.
-enum ResourceStateEvent {
- RS_BUFFER_AVAILABLE,
- RS_BUFFER_UNAVAILABLE,
- RS_RESERVED
-};
-
-/// Resource allocation strategy used by hardware scheduler resources.
-class ResourceStrategy {
- ResourceStrategy(const ResourceStrategy &) = delete;
- ResourceStrategy &operator=(const ResourceStrategy &) = delete;
-
-public:
- ResourceStrategy() {}
- virtual ~ResourceStrategy();
-
- /// Selects a processor resource unit from a ReadyMask.
- virtual uint64_t select(uint64_t ReadyMask) = 0;
-
- /// Called by the ResourceManager when a processor resource group, or a
- /// processor resource with multiple units has become unavailable.
- ///
- /// The default strategy uses this information to bias its selection logic.
- virtual void used(uint64_t ResourceMask) {}
-};
-
-/// Default resource allocation strategy used by processor resource groups and
-/// processor resources with multiple units.
-class DefaultResourceStrategy final : public ResourceStrategy {
- /// A Mask of resource unit identifiers.
- ///
- /// There is one bit set for every available resource unit.
- /// It defaults to the value of field ResourceSizeMask in ResourceState.
- const unsigned ResourceUnitMask;
-
- /// A simple round-robin selector for processor resource units.
- /// Each bit of this mask identifies a sub resource within a group.
- ///
- /// As an example, lets assume that this is a default policy for a
- /// processor resource group composed by the following three units:
- /// ResourceA -- 0b001
- /// ResourceB -- 0b010
- /// ResourceC -- 0b100
- ///
- /// Field NextInSequenceMask is used to select the next unit from the set of
- /// resource units. It defaults to the value of field `ResourceUnitMasks` (in
- /// this example, it defaults to mask '0b111').
- ///
- /// The round-robin selector would firstly select 'ResourceC', then
- /// 'ResourceB', and eventually 'ResourceA'. When a resource R is used, the
- /// corresponding bit in NextInSequenceMask is cleared. For example, if
- /// 'ResourceC' is selected, then the new value of NextInSequenceMask becomes
- /// 0xb011.
- ///
- /// When NextInSequenceMask becomes zero, it is automatically reset to the
- /// default value (i.e. ResourceUnitMask).
- uint64_t NextInSequenceMask;
-
- /// This field is used to track resource units that are used (i.e. selected)
- /// by other groups other than the one associated with this strategy object.
- ///
- /// In LLVM processor resource groups are allowed to partially (or fully)
- /// overlap. That means, a same unit may be visible to multiple groups.
- /// This field keeps track of uses that have originated from outside of
- /// this group. The idea is to bias the selection strategy, so that resources
- /// that haven't been used by other groups get prioritized.
- ///
- /// The end goal is to (try to) keep the resource distribution as much uniform
- /// as possible. By construction, this mask only tracks one-level of resource
- /// usage. Therefore, this strategy is expected to be less accurate when same
- /// units are used multiple times by other groups within a single round of
- /// select.
- ///
- /// Note: an LRU selector would have a better accuracy at the cost of being
- /// slightly more expensive (mostly in terms of runtime cost). Methods
- /// 'select' and 'used', are always in the hot execution path of llvm-mca.
- /// Therefore, a slow implementation of 'select' would have a negative impact
- /// on the overall performance of the tool.
- uint64_t RemovedFromNextInSequence;
-
- void skipMask(uint64_t Mask);
-
-public:
- DefaultResourceStrategy(uint64_t UnitMask)
- : ResourceStrategy(), ResourceUnitMask(UnitMask),
- NextInSequenceMask(UnitMask), RemovedFromNextInSequence(0) {}
- virtual ~DefaultResourceStrategy() = default;
-
- uint64_t select(uint64_t ReadyMask) override;
- void used(uint64_t Mask) override;
-};
-
-/// A processor resource descriptor.
-///
-/// There is an instance of this class for every processor resource defined by
-/// the machine scheduling model.
-/// Objects of class ResourceState dynamically track the usage of processor
-/// resource units.
-class ResourceState {
- /// An index to the MCProcResourceDesc entry in the processor model.
- const unsigned ProcResourceDescIndex;
- /// A resource mask. This is generated by the tool with the help of
- /// function `mca::createProcResourceMasks' (see Support.h).
- const uint64_t ResourceMask;
-
- /// A ProcResource can have multiple units.
- ///
- /// For processor resource groups,
- /// this field default to the value of field `ResourceMask`; the number of
- /// bits set is equal to the cardinality of the group. For normal (i.e.
- /// non-group) resources, the number of bits set in this mask is equivalent
- /// to the number of units declared by the processor model (see field
- /// 'NumUnits' in 'ProcResourceUnits').
- uint64_t ResourceSizeMask;
-
- /// A mask of ready units.
- uint64_t ReadyMask;
-
- /// Buffered resources will have this field set to a positive number different
- /// than zero. A buffered resource behaves like a reservation station
- /// implementing its own buffer for out-of-order execution.
- ///
- /// A BufferSize of 1 is used by scheduler resources that force in-order
- /// execution.
- ///
- /// A BufferSize of 0 is used to model in-order issue/dispatch resources.
- /// Since in-order issue/dispatch resources don't implement buffers, dispatch
- /// events coincide with issue events.
- /// Also, no other instruction ca be dispatched/issue while this resource is
- /// in use. Only when all the "resource cycles" are consumed (after the issue
- /// event), a new instruction ca be dispatched.
- const int BufferSize;
-
- /// Available slots in the buffer (zero, if this is not a buffered resource).
- unsigned AvailableSlots;
-
- /// This field is set if this resource is currently reserved.
- ///
- /// Resources can be reserved for a number of cycles.
- /// Instructions can still be dispatched to reserved resources. However,
- /// istructions dispatched to a reserved resource cannot be issued to the
- /// underlying units (i.e. pipelines) until the resource is released.
- bool Unavailable;
-
- /// Checks for the availability of unit 'SubResMask' in the group.
- bool isSubResourceReady(uint64_t SubResMask) const {
- return ReadyMask & SubResMask;
- }
-
-public:
- ResourceState(const llvm::MCProcResourceDesc &Desc, unsigned Index,
- uint64_t Mask);
-
- unsigned getProcResourceID() const { return ProcResourceDescIndex; }
- uint64_t getResourceMask() const { return ResourceMask; }
- uint64_t getReadyMask() const { return ReadyMask; }
- int getBufferSize() const { return BufferSize; }
-
- bool isBuffered() const { return BufferSize > 0; }
- bool isInOrder() const { return BufferSize == 1; }
-
- /// Returns true if this is an in-order dispatch/issue resource.
- bool isADispatchHazard() const { return BufferSize == 0; }
- bool isReserved() const { return Unavailable; }
-
- void setReserved() { Unavailable = true; }
- void clearReserved() { Unavailable = false; }
-
- /// Returs true if this resource is not reserved, and if there are at least
- /// `NumUnits` available units.
- bool isReady(unsigned NumUnits = 1) const;
-
- bool isAResourceGroup() const {
- return llvm::countPopulation(ResourceMask) > 1;
- }
-
- bool containsResource(uint64_t ID) const { return ResourceMask & ID; }
-
- void markSubResourceAsUsed(uint64_t ID) {
- assert(isSubResourceReady(ID));
- ReadyMask ^= ID;
- }
-
- void releaseSubResource(uint64_t ID) {
- assert(!isSubResourceReady(ID));
- ReadyMask ^= ID;
- }
-
- unsigned getNumUnits() const {
- return isAResourceGroup() ? 1U : llvm::countPopulation(ResourceSizeMask);
- }
-
- /// Checks if there is an available slot in the resource buffer.
- ///
- /// Returns RS_BUFFER_AVAILABLE if this is not a buffered resource, or if
- /// there is a slot available.
- ///
- /// Returns RS_RESERVED if this buffered resource is a dispatch hazard, and it
- /// is reserved.
- ///
- /// Returns RS_BUFFER_UNAVAILABLE if there are no available slots.
- ResourceStateEvent isBufferAvailable() const;
-
- /// Reserve a slot in the buffer.
- void reserveBuffer() {
- if (AvailableSlots)
- AvailableSlots--;
- }
-
- /// Release a slot in the buffer.
- void releaseBuffer() {
- if (BufferSize > 0)
- AvailableSlots++;
- assert(AvailableSlots <= static_cast<unsigned>(BufferSize));
- }
-
-#ifndef NDEBUG
- void dump() const;
-#endif
-};
-
-/// A resource unit identifier.
-///
-/// This is used to identify a specific processor resource unit using a pair
-/// of indices where the 'first' index is a processor resource mask, and the
-/// 'second' index is an index for a "sub-resource" (i.e. unit).
-typedef std::pair<uint64_t, uint64_t> ResourceRef;
-
-// First: a MCProcResourceDesc index identifying a buffered resource.
-// Second: max number of buffer entries used in this resource.
-typedef std::pair<unsigned, unsigned> BufferUsageEntry;
-
-/// A resource manager for processor resource units and groups.
-///
-/// This class owns all the ResourceState objects, and it is responsible for
-/// acting on requests from a Scheduler by updating the internal state of
-/// ResourceState objects.
-/// This class doesn't know about instruction itineraries and functional units.
-/// In future, it can be extended to support itineraries too through the same
-/// public interface.
-class ResourceManager {
- // The resource manager owns all the ResourceState.
- std::vector<std::unique_ptr<ResourceState>> Resources;
- std::vector<std::unique_ptr<ResourceStrategy>> Strategies;
-
- // Keeps track of which resources are busy, and how many cycles are left
- // before those become usable again.
- llvm::SmallDenseMap<ResourceRef, unsigned> BusyResources;
-
- // A table to map processor resource IDs to processor resource masks.
- llvm::SmallVector<uint64_t, 8> ProcResID2Mask;
-
- // Returns the actual resource unit that will be used.
- ResourceRef selectPipe(uint64_t ResourceID);
-
- void use(const ResourceRef &RR);
- void release(const ResourceRef &RR);
-
- unsigned getNumUnits(uint64_t ResourceID) const;
-
- // Overrides the selection strategy for the processor resource with the given
- // mask.
- void setCustomStrategyImpl(std::unique_ptr<ResourceStrategy> S,
- uint64_t ResourceMask);
-
-public:
- ResourceManager(const llvm::MCSchedModel &SM);
- virtual ~ResourceManager() = default;
-
- // Overrides the selection strategy for the resource at index ResourceID in
- // the MCProcResourceDesc table.
- void setCustomStrategy(std::unique_ptr<ResourceStrategy> S,
- unsigned ResourceID) {
- assert(ResourceID < ProcResID2Mask.size() &&
- "Invalid resource index in input!");
- return setCustomStrategyImpl(std::move(S), ProcResID2Mask[ResourceID]);
- }
-
- // Returns RS_BUFFER_AVAILABLE if buffered resources are not reserved, and if
- // there are enough available slots in the buffers.
- ResourceStateEvent canBeDispatched(llvm::ArrayRef<uint64_t> Buffers) const;
-
- // Return the processor resource identifier associated to this Mask.
- 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.
- void reserveBuffers(llvm::ArrayRef<uint64_t> Buffers);
-
- // Release buffer entries previously allocated by method reserveBuffers.
- void releaseBuffers(llvm::ArrayRef<uint64_t> Buffers);
-
- // Reserve a processor resource. A reserved resource is not available for
- // instruction issue until it is released.
- void reserveResource(uint64_t ResourceID);
-
- // 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).
- bool mustIssueImmediately(const InstrDesc &Desc) const;
-
- bool canBeIssued(const InstrDesc &Desc) const;
-
- void issueInstruction(
- const InstrDesc &Desc,
- llvm::SmallVectorImpl<std::pair<ResourceRef, double>> &Pipes);
-
- void cycleEvent(llvm::SmallVectorImpl<ResourceRef> &ResourcesFreed);
-
-#ifndef NDEBUG
- void dump() const {
- for (const std::unique_ptr<ResourceState> &Resource : Resources)
- Resource->dump();
- }
-#endif
-}; // namespace mca
-
class SchedulerStrategy {
public:
SchedulerStrategy() = default;