source: vis_dev/glu-2.3/src/calBdd/calGC.c @ 104

Last change on this file since 104 was 13, checked in by cecile, 14 years ago

library glu 2.3
File size: 16.8 KB
RevLine 
[13]1/**CFile***********************************************************************
2
3  FileName    [calGC.c]
4
5  PackageName [cal]
6
7  Synopsis    [Garbage collection routines]
8
9  Description [optional]
10
11  SeeAlso     [optional]
12
13  Author      [Jagesh Sanghavi (sanghavi@eecs.berkeley.edu)
14               Rajeev Ranjan (rajeev@eecs.berkeley.edu)]
15
16  Copyright   [Copyright (c) 1994-1996 The Regents of the Univ. of California.
17  All rights reserved.
18
19  Permission is hereby granted, without written agreement and without license
20  or royalty fees, to use, copy, modify, and distribute this software and its
21  documentation for any purpose, provided that the above copyright notice and
22  the following two paragraphs appear in all copies of this software.
23
24  IN NO EVENT SHALL THE UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY FOR
25  DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING OUT
26  OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF THE UNIVERSITY OF
27  CALIFORNIA HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28
29  THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY WARRANTIES,
30  INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
31  FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS ON AN
32  "AS IS" BASIS, AND THE UNIVERSITY OF CALIFORNIA HAS NO OBLIGATION TO PROVIDE
33  MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.]
34
35  Revision    [$Id: calGC.c,v 1.2 1998/09/16 16:08:40 ravi Exp $]
36
37******************************************************************************/
38
39#include "calInt.h"
40
41
42/*---------------------------------------------------------------------------*/
43/* Constant declarations                                                     */
44/*---------------------------------------------------------------------------*/
45
46/*---------------------------------------------------------------------------*/
47/* Type declarations                                                         */
48/*---------------------------------------------------------------------------*/
49
50/*---------------------------------------------------------------------------*/
51/* Stucture declarations                                                     */
52/*---------------------------------------------------------------------------*/
53
54/*---------------------------------------------------------------------------*/
55/* Variable declarations                                                     */
56/*---------------------------------------------------------------------------*/
57
58/*---------------------------------------------------------------------------*/
59/* Macro declarations                                                        */
60/*---------------------------------------------------------------------------*/
61
62/**AutomaticStart*************************************************************/
63
64/*---------------------------------------------------------------------------*/
65/* Static function prototypes                                                */
66/*---------------------------------------------------------------------------*/
67
68static int CeilLog2(int number);
69
70/**AutomaticEnd***************************************************************/
71
72
73/*---------------------------------------------------------------------------*/
74/* Definition of exported functions                                          */
75/*---------------------------------------------------------------------------*/
76/**Function********************************************************************
77
78  Synopsis    [Sets the garbage collection mode, 0 means the garbage
79  collection should be turned off, 1 means garbage collection should
80  be on.]
81
82  Description [Sets the garbage collection mode, 0 means the garbage
83  collection should be turned off, 1 means garbage collection should
84  be on.]
85
86  SideEffects [None.]
87
88******************************************************************************/
89void
90Cal_BddSetGCMode(
91  Cal_BddManager bddManager,
92  int  gcMode)
93{
94  bddManager->gcMode = gcMode;
95}
96
97
98/**Function********************************************************************
99
100  Synopsis    [Invokes the garbage collection at the manager level.]
101
102  Description [For each variable in the increasing id free nodes with reference
103  count equal to zero freeing a node results in decrementing reference count of
104  then and else nodes by one.]
105
106  SideEffects [None.]
107
108******************************************************************************/
109int
110Cal_BddManagerGC(Cal_BddManager bddManager)
111{
112  Cal_BddIndex_t index;
113  Cal_BddId_t id;
114  int numNodesFreed;
115  /* unsigned long origNodes = bddManager->numNodes; */
116 
117  if (bddManager->numPeakNodes < (bddManager->numNodes +
118                                  bddManager->numForwardedNodes)){
119    bddManager->numPeakNodes = bddManager->numNodes +
120        bddManager->numForwardedNodes ;
121  }
122 
123  CalHashTableGC(bddManager, bddManager->uniqueTable[0]);
124  for(index = 0; index < bddManager->numVars; index++){
125    id = bddManager->indexToId[index];
126    numNodesFreed = CalHashTableGC(bddManager, bddManager->uniqueTable[id]);
127    bddManager->numNodes -= numNodesFreed;
128    bddManager->numNodesFreed += numNodesFreed;
129  }
130  /* Free the cache entries related to unused BDD nodes */
131  /* The assumption is that during CalHashTableGC, the freed BDD nodes
132     are marked. However, since they are not touched after being put
133     on the free list, the mark should be unaffected and can be used
134     for cleaning up the cache table.
135     */
136  CalCacheTableTwoGCFlush(bddManager->cacheTable);
137  bddManager->numGC++;
138  return 0;
139}
140
141/**Function********************************************************************
142
143  Synopsis    [Sets the limit of the garbage collection.]
144
145  Description [It tries to set the limit at twice the number of nodes
146  in the manager at the current point. However, the limit is not
147  allowed to fall below the MIN_GC_LIMIT or to exceed the value of
148  node limit (if one exists).]
149
150  SideEffects [None.]
151
152******************************************************************************/
153void
154Cal_BddManagerSetGCLimit(Cal_BddManager manager)
155{
156  manager->uniqueTableGCLimit = ((manager->numNodes) << 1);
157  if(manager->uniqueTableGCLimit < CAL_MIN_GC_LIMIT){
158    manager->uniqueTableGCLimit = CAL_MIN_GC_LIMIT;
159  }
160  if (manager->nodeLimit && (manager->uniqueTableGCLimit >
161                             manager->nodeLimit)){
162    manager->uniqueTableGCLimit = manager->nodeLimit;
163  }
164}
165
166/*---------------------------------------------------------------------------*/
167/* Definition of internal functions                                          */
168/*---------------------------------------------------------------------------*/
169/**Function********************************************************************
170
171  Synopsis    [required]
172
173  Description [optional]
174
175  SideEffects [required]
176
177  SeeAlso     [optional]
178
179******************************************************************************/
180void
181CalBddManagerGCCheck(Cal_BddManager_t * bddManager)
182{
183  if (bddManager->gcMode == 0) return;
184  if (bddManager->gcCheck > 0) return;
185  bddManager->gcCheck = CAL_GC_CHECK;
186  if(bddManager->numNodes > bddManager->uniqueTableGCLimit){
187    Cal_BddManagerGC(bddManager);
188    Cal_BddManagerSetGCLimit(bddManager);
189  }
190}
191
192/**Function********************************************************************
193
194  Synopsis    [This function performs the garbage collection operation
195  for a particular index.]
196
197  Description [The input is the hash table containing the nodes
198  belonging to that level. Each bin of the hash table is traversed and
199  the Bdd nodes with 0 reference count are put at the appropriate
200  level in the processing que of the manager.]
201
202  SideEffects [The number of nodes in the hash table can possibly decrease.]
203
204  SeeAlso     [optional]
205
206******************************************************************************/
207int
208CalHashTableGC(Cal_BddManager_t *bddManager, CalHashTable_t *hashTable)
209{
210  CalBddNode_t *last, *next, *ptr, *thenBddNode, *elseBddNode;
211  int i;
212  int oldNumEntries;
213 
214  oldNumEntries = hashTable->numEntries;
215  for(i = 0; i < hashTable->numBins; i++){
216    last = NULL;
217    ptr = hashTable->bins[i];
218    while(ptr != Cal_Nil(CalBddNode_t)){
219      next = CalBddNodeGetNextBddNode(ptr);
220      if(CalBddNodeIsRefCountZero(ptr)){
221        if (last == NULL){
222          hashTable->bins[i] = next;
223        }
224        else{
225          CalBddNodePutNextBddNode(last,next);
226        }
227        thenBddNode = CAL_BDD_POINTER(CalBddNodeGetThenBddNode(ptr));
228        elseBddNode = CAL_BDD_POINTER(CalBddNodeGetElseBddNode(ptr));
229        CalBddNodeDcrRefCount(thenBddNode);
230        CalBddNodeDcrRefCount(elseBddNode);
231        CalNodeManagerFreeNode(hashTable->nodeManager, ptr);
232        /* Mark the freed node for cache table clean up */
233        /* We have to make sure that the clean up routine is called */
234        /* right after this function (so that the marking remains */
235        /* valid) */
236        CalBddNodeMark(ptr);
237        hashTable->numEntries--;
238      }
239      else {
240        last = ptr;
241      }
242      ptr = next;
243    }
244  }
245  return oldNumEntries - hashTable->numEntries;
246}
247
248
249/**Function********************************************************************
250
251  Synopsis           [required]
252
253  Description        [optional]
254
255  SideEffects        [required]
256
257  SeeAlso            [optional]
258
259******************************************************************************/
260void
261CalRepackNodesAfterGC(Cal_BddManager_t *bddManager)
262{
263  int index, id, numPagesRequired, packingFlag, pageNum, nodeNum;
264  int rehashFlag = 0;
265  int newSizeIndex, hashValue;
266  CalNodeManager_t *nodeManager;
267  CalHashTable_t *uniqueTableForId;
268  CalBddNode_t *bddNode, *thenBddNode, *elseBddNode, *freeNodeList;
269  CalBddNode_t *newNode;
270  Cal_Bdd_t thenBdd, elseBdd;
271 
272  packingFlag = 0;
273 
274  for (index = bddManager->numVars-1; index >= 0; index--){
275    id = bddManager->indexToId[index];
276    uniqueTableForId = bddManager->uniqueTable[id];
277    nodeManager = uniqueTableForId->nodeManager;
278    if (CalBddIdNeedsRepacking(bddManager, id) == 0){
279      if (packingFlag == 0) continue; /* nothing needs to be done */
280      /* We just need to update the cofactors and continue; */
281      for (pageNum=0; pageNum < nodeManager->numPages; pageNum++){
282        for(nodeNum = 0,
283                bddNode = (CalBddNode_t *)nodeManager->pageList[pageNum]; 
284            nodeNum < NUM_NODES_PER_PAGE; nodeNum++, bddNode += 1){
285          if (CalBddNodeIsRefCountZero(bddNode) ||
286              CalBddNodeIsForwarded(bddNode)) continue;
287          thenBddNode = CalBddNodeGetThenBddNode(bddNode);
288          elseBddNode = CalBddNodeGetElseBddNode(bddNode);
289          CalBddNodeGetThenBdd(bddNode, thenBdd);
290          CalBddNodeGetElseBdd(bddNode, elseBdd);
291          if (CalBddIsForwarded(thenBdd)){
292            CalBddForward(thenBdd);
293            CalBddNodePutThenBdd(bddNode, thenBdd);
294            rehashFlag = 1;
295          }
296          if (CalBddIsForwarded(elseBdd)){
297            CalBddForward(elseBdd);
298            CalBddNodePutElseBdd(bddNode, elseBdd);
299            rehashFlag = 1;
300          }
301          Cal_Assert(!CalBddIsRefCountZero(thenBdd));
302          Cal_Assert(!CalBddIsRefCountZero(elseBdd));
303          Cal_Assert(bddManager->idToIndex[id] <
304                     bddManager->idToIndex[bddNode->thenBddId]);   
305          Cal_Assert(bddManager->idToIndex[id] < 
306                     bddManager->idToIndex[bddNode->elseBddId]);
307          if (rehashFlag){
308            CalUniqueTableForIdRehashNode(uniqueTableForId, bddNode,
309                                          thenBddNode, elseBddNode);
310          }
311        }
312      }
313      continue; /* move to next higher index */
314    }
315    packingFlag = 1;
316    if ((uniqueTableForId->numBins > uniqueTableForId->numEntries) &&
317        (uniqueTableForId->sizeIndex > HASH_TABLE_DEFAULT_SIZE_INDEX)){
318      /* Free the old bins */
319      Cal_MemFree(uniqueTableForId->bins);
320      /* Create the new set of bins */
321      newSizeIndex =
322          CeilLog2(uniqueTableForId->numEntries/HASH_TABLE_DEFAULT_MAX_DENSITY); 
323      if (newSizeIndex < HASH_TABLE_DEFAULT_SIZE_INDEX){
324        newSizeIndex = HASH_TABLE_DEFAULT_SIZE_INDEX;
325      }
326      uniqueTableForId->sizeIndex = newSizeIndex;
327      uniqueTableForId->numBins =  TABLE_SIZE(uniqueTableForId->sizeIndex);
328      uniqueTableForId->maxCapacity =
329          uniqueTableForId->numBins * HASH_TABLE_DEFAULT_MAX_DENSITY; 
330      uniqueTableForId->bins = Cal_MemAlloc(CalBddNode_t *,
331                                            uniqueTableForId->numBins); 
332      if(uniqueTableForId->bins == Cal_Nil(CalBddNode_t *)){
333        CalBddFatalMessage("out of memory");
334      }
335    }
336    /* Clear the unique table bins */
337    memset((char *)uniqueTableForId->bins, 0,
338           uniqueTableForId->numBins*sizeof(CalBddNode_t *));
339    numPagesRequired =
340        uniqueTableForId->numEntries/NUM_NODES_PER_PAGE+1;
341    /* Traverse the first numPagesRequired pages of this nodeManager */
342    /* Create the new free list */
343    nodeManager->freeNodeList = freeNodeList = Cal_Nil(CalBddNode_t);
344    for (pageNum = 0; pageNum < nodeManager->numPages; pageNum++){
345      for(nodeNum = 0,
346              bddNode = (CalBddNode_t *)nodeManager->pageList[pageNum]; 
347          nodeNum < NUM_NODES_PER_PAGE; nodeNum++, bddNode += 1){
348        if(CalBddNodeIsRefCountZero(bddNode) ||
349           CalBddNodeIsForwarded(bddNode)){
350          if (pageNum < numPagesRequired){
351            bddNode->nextBddNode = freeNodeList;
352            freeNodeList = bddNode;
353          }
354          continue;
355        }
356        CalBddNodeGetThenBdd(bddNode, thenBdd);
357        CalBddNodeGetElseBdd(bddNode, elseBdd);
358        if (CalBddIsForwarded(thenBdd)){
359          CalBddForward(thenBdd);
360          CalBddNodePutThenBdd(bddNode, thenBdd);
361        }
362        if (CalBddIsForwarded(elseBdd)){
363          CalBddForward(elseBdd);
364          CalBddNodePutElseBdd(bddNode, elseBdd); 
365        }
366        if (pageNum < numPagesRequired){
367          /* Simply insert the node in the unique table */
368          hashValue = CalDoHash2(thenBdd.bddNode, elseBdd.bddNode,
369                                 uniqueTableForId); 
370          CalBddNodePutNextBddNode(bddNode, uniqueTableForId->bins[hashValue]);
371          uniqueTableForId->bins[hashValue] = bddNode;
372        }
373        else {
374          /* Create a new node */
375          newNode = freeNodeList;
376          freeNodeList = newNode->nextBddNode;
377          newNode->thenBddNode = bddNode->thenBddNode;
378          newNode->elseBddNode = bddNode->elseBddNode;
379          newNode->thenBddId = bddNode->thenBddId;
380          newNode->elseBddId = bddNode->elseBddId;
381          newNode->nextBddNode = bddNode->nextBddNode;
382          bddNode->elseBddNode = FORWARD_FLAG;
383          bddNode->thenBddId = id;
384          bddNode->thenBddNode = newNode;
385          hashValue = CalDoHash2(thenBdd.bddNode, elseBdd.bddNode,
386                                 uniqueTableForId); 
387          CalBddNodePutNextBddNode(newNode, uniqueTableForId->bins[hashValue]);
388          uniqueTableForId->bins[hashValue] = newNode;
389        }
390      }
391      if (pageNum >= numPagesRequired){
392        /* Free this page. I am assuming that there would not be any
393           call to PageManagerAllocPage, until this function finishes */
394        /* Also, CalPageManagerFreePage overwrites only the first field of
395           the bdd node (the nextBddNode field), hence no relevant
396           information is lost */
397        CalPageManagerFreePage(nodeManager->pageManager,
398                               nodeManager->pageList[pageNum]);
399        nodeManager->pageList[pageNum] = 0;
400      }
401    }
402#ifdef _CAL_VERBOSE   
403    printf("Recycled %4d pages for %3d id\n",
404           nodeManager->numPages-numPagesRequired, id);
405#endif
406    nodeManager->numPages = numPagesRequired;
407    nodeManager->freeNodeList = freeNodeList;
408  }
409  /* Need to update the handles to the nodes being moved */
410  if (bddManager->pipelineState == CREATE){
411    /* There are some results computed in pipeline */
412    CalBddReorderFixProvisionalNodes(bddManager);
413  }
414 
415  CalCacheTableTwoRepackUpdate(bddManager->cacheTable);
416
417  /* Fix the user BDDs */
418  CalBddReorderFixUserBddPtrs(bddManager);
419
420  /* Fix the association */
421  CalReorderAssociationFix(bddManager);
422
423  Cal_Assert(CalCheckAssoc(bddManager));
424}
425
426/*---------------------------------------------------------------------------*/
427/* Definition of static functions                                            */
428/*---------------------------------------------------------------------------*/
429
430/**Function********************************************************************
431
432  Synopsis    [Returns the smallest integer greater than or equal to log2 of a
433  number]
434
435  Description [Returns the smallest integer greater than or equal to log2 of a
436  number (The assumption is that the number is >= 1)]
437
438  SideEffects [None]
439
440******************************************************************************/
441static int
442CeilLog2(int  number)
443{
444  int num, count;
445  for (num=number, count=0; num > 1; num >>= 1, count++);
446  if ((1 << count) != number) count++;
447  return count;
448}
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