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Diffstat (limited to 'src/cpu/o3/dep_graph.hh')
| -rw-r--r-- | src/cpu/o3/dep_graph.hh | 264 |
1 files changed, 264 insertions, 0 deletions
diff --git a/src/cpu/o3/dep_graph.hh b/src/cpu/o3/dep_graph.hh new file mode 100644 index 000000000..3659b1a37 --- /dev/null +++ b/src/cpu/o3/dep_graph.hh @@ -0,0 +1,264 @@ +/* + * Copyright (c) 2006 The Regents of The University of Michigan + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are + * met: redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer; + * redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution; + * neither the name of the copyright holders nor the names of its + * contributors may be used to endorse or promote products derived from + * this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT + * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + * + * Authors: Kevin Lim + */ + +#ifndef __CPU_O3_DEP_GRAPH_HH__ +#define __CPU_O3_DEP_GRAPH_HH__ + +#include "cpu/o3/comm.hh" + +/** Node in a linked list. */ +template <class DynInstPtr> +class DependencyEntry +{ + public: + DependencyEntry() + : inst(NULL), next(NULL) + { } + + DynInstPtr inst; + //Might want to include data about what arch. register the + //dependence is waiting on. + DependencyEntry<DynInstPtr> *next; +}; + +/** Array of linked list that maintains the dependencies between + * producing instructions and consuming instructions. Each linked + * list represents a single physical register, having the future + * producer of the register's value, and all consumers waiting on that + * value on the list. The head node of each linked list represents + * the producing instruction of that register. Instructions are put + * on the list upon reaching the IQ, and are removed from the list + * either when the producer completes, or the instruction is squashed. +*/ +template <class DynInstPtr> +class DependencyGraph +{ + public: + typedef DependencyEntry<DynInstPtr> DepEntry; + + /** Default construction. Must call resize() prior to use. */ + DependencyGraph() + : numEntries(0), memAllocCounter(0), nodesTraversed(0), nodesRemoved(0) + { } + + /** Resize the dependency graph to have num_entries registers. */ + void resize(int num_entries); + + /** Clears all of the linked lists. */ + void reset(); + + /** Inserts an instruction to be dependent on the given index. */ + void insert(PhysRegIndex idx, DynInstPtr &new_inst); + + /** Sets the producing instruction of a given register. */ + void setInst(PhysRegIndex idx, DynInstPtr &new_inst) + { dependGraph[idx].inst = new_inst; } + + /** Clears the producing instruction. */ + void clearInst(PhysRegIndex idx) + { dependGraph[idx].inst = NULL; } + + /** Removes an instruction from a single linked list. */ + void remove(PhysRegIndex idx, DynInstPtr &inst_to_remove); + + /** Removes and returns the newest dependent of a specific register. */ + DynInstPtr pop(PhysRegIndex idx); + + /** Checks if there are any dependents on a specific register. */ + bool empty(PhysRegIndex idx) { return !dependGraph[idx].next; } + + /** Debugging function to dump out the dependency graph. + */ + void dump(); + + private: + /** Array of linked lists. Each linked list is a list of all the + * instructions that depend upon a given register. The actual + * register's index is used to index into the graph; ie all + * instructions in flight that are dependent upon r34 will be + * in the linked list of dependGraph[34]. + */ + DepEntry *dependGraph; + + /** Number of linked lists; identical to the number of registers. */ + int numEntries; + + // Debug variable, remove when done testing. + unsigned memAllocCounter; + + public: + // Debug variable, remove when done testing. + uint64_t nodesTraversed; + // Debug variable, remove when done testing. + uint64_t nodesRemoved; +}; + +template <class DynInstPtr> +void +DependencyGraph<DynInstPtr>::resize(int num_entries) +{ + numEntries = num_entries; + dependGraph = new DepEntry[numEntries]; +} + +template <class DynInstPtr> +void +DependencyGraph<DynInstPtr>::reset() +{ + // Clear the dependency graph + DepEntry *curr; + DepEntry *prev; + + for (int i = 0; i < numEntries; ++i) { + curr = dependGraph[i].next; + + while (curr) { + memAllocCounter--; + + prev = curr; + curr = prev->next; + prev->inst = NULL; + + delete prev; + } + + if (dependGraph[i].inst) { + dependGraph[i].inst = NULL; + } + + dependGraph[i].next = NULL; + } +} + +template <class DynInstPtr> +void +DependencyGraph<DynInstPtr>::insert(PhysRegIndex idx, DynInstPtr &new_inst) +{ + //Add this new, dependent instruction at the head of the dependency + //chain. + + // First create the entry that will be added to the head of the + // dependency chain. + DepEntry *new_entry = new DepEntry; + new_entry->next = dependGraph[idx].next; + new_entry->inst = new_inst; + + // Then actually add it to the chain. + dependGraph[idx].next = new_entry; + + ++memAllocCounter; +} + + +template <class DynInstPtr> +void +DependencyGraph<DynInstPtr>::remove(PhysRegIndex idx, + DynInstPtr &inst_to_remove) +{ + DepEntry *prev = &dependGraph[idx]; + DepEntry *curr = dependGraph[idx].next; + + // Make sure curr isn't NULL. Because this instruction is being + // removed from a dependency list, it must have been placed there at + // an earlier time. The dependency chain should not be empty, + // unless the instruction dependent upon it is already ready. + if (curr == NULL) { + return; + } + + nodesRemoved++; + + // Find the instruction to remove within the dependency linked list. + while (curr->inst != inst_to_remove) { + prev = curr; + curr = curr->next; + nodesTraversed++; + + assert(curr != NULL); + } + + // Now remove this instruction from the list. + prev->next = curr->next; + + --memAllocCounter; + + // Could push this off to the destructor of DependencyEntry + curr->inst = NULL; + + delete curr; +} + +template <class DynInstPtr> +DynInstPtr +DependencyGraph<DynInstPtr>::pop(PhysRegIndex idx) +{ + DepEntry *node; + node = dependGraph[idx].next; + DynInstPtr inst = NULL; + if (node) { + inst = node->inst; + dependGraph[idx].next = node->next; + node->inst = NULL; + memAllocCounter--; + delete node; + } + return inst; +} + +template <class DynInstPtr> +void +DependencyGraph<DynInstPtr>::dump() +{ + DepEntry *curr; + + for (int i = 0; i < numEntries; ++i) + { + curr = &dependGraph[i]; + + if (curr->inst) { + cprintf("dependGraph[%i]: producer: %#x [sn:%lli] consumer: ", + i, curr->inst->readPC(), curr->inst->seqNum); + } else { + cprintf("dependGraph[%i]: No producer. consumer: ", i); + } + + while (curr->next != NULL) { + curr = curr->next; + + cprintf("%#x [sn:%lli] ", + curr->inst->readPC(), curr->inst->seqNum); + } + + cprintf("\n"); + } + cprintf("memAllocCounter: %i\n", memAllocCounter); +} + +#endif // __CPU_O3_DEP_GRAPH_HH__ |