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Overview
Comment: | Attempt to use two cores to do sorting. Unfortunately, instead of making sorts go faster as was hoped, this changes slows sorting down by about 10%. (Later:) The previous measurement was compiled using -pg. When compiled using -Os, this new code is roughly 10% faster than the original. |
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SHA1: |
11dd05e5984f0d5f98052458b94cbaf7 |
User & Date: | drh 2012-08-16 20:05:43.061 |
Original Comment: | Attempt to use two cores to do sorting. Unfortunately, instead of making sorts go faster as was hoped, this changes slows sorting down by about 10%. |
Context
2012-08-20
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12:36 | Changes to the thread routines to disable them when threading is turned off using sqlite3_config(). (check-in: 555fc07efd user: drh tags: threads-sort-ex1) | |
2012-08-16
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20:05 | Attempt to use two cores to do sorting. Unfortunately, instead of making sorts go faster as was hoped, this changes slows sorting down by about 10%. (Later:) The previous measurement was compiled using -pg. When compiled using -Os, this new code is roughly 10% faster than the original. (check-in: 11dd05e598 user: drh tags: threads-sort-ex1) | |
11:24 | Update the threads branch to include all the latest trunk changes. (check-in: f4125771e2 user: drh tags: threads) | |
Changes
Changes to src/vdbesort.c.
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101 102 103 104 105 106 107 108 109 110 111 112 113 114 | int nPMA; /* Number of PMAs stored in pTemp1 */ int mnPmaSize; /* Minimum PMA size, in bytes */ int mxPmaSize; /* Maximum PMA size, in bytes. 0==no limit */ VdbeSorterIter *aIter; /* Array of iterators to merge */ int *aTree; /* Current state of incremental merge */ sqlite3_file *pTemp1; /* PMA file 1 */ SorterRecord *pRecord; /* Head of in-memory record list */ UnpackedRecord *pUnpacked; /* Used to unpack keys */ }; /* ** The following type is an iterator for a PMA. It caches the current key in ** variables nKey/aKey. If the iterator is at EOF, pFile==0. */ | > | 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 | int nPMA; /* Number of PMAs stored in pTemp1 */ int mnPmaSize; /* Minimum PMA size, in bytes */ int mxPmaSize; /* Maximum PMA size, in bytes. 0==no limit */ VdbeSorterIter *aIter; /* Array of iterators to merge */ int *aTree; /* Current state of incremental merge */ sqlite3_file *pTemp1; /* PMA file 1 */ SorterRecord *pRecord; /* Head of in-memory record list */ int nRecord; /* Number of elements on the pRecord list */ UnpackedRecord *pUnpacked; /* Used to unpack keys */ }; /* ** The following type is an iterator for a PMA. It caches the current key in ** variables nKey/aKey. If the iterator is at EOF, pFile==0. */ |
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383 384 385 386 387 388 389 | ** has been allocated and contains an unpacked record that is used as key2. */ static void vdbeSorterCompare( const VdbeCursor *pCsr, /* Cursor object (for pKeyInfo) */ int bOmitRowid, /* Ignore rowid field at end of keys */ const void *pKey1, int nKey1, /* Left side of comparison */ const void *pKey2, int nKey2, /* Right side of comparison */ | | > < < > | 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 | ** has been allocated and contains an unpacked record that is used as key2. */ static void vdbeSorterCompare( const VdbeCursor *pCsr, /* Cursor object (for pKeyInfo) */ int bOmitRowid, /* Ignore rowid field at end of keys */ const void *pKey1, int nKey1, /* Left side of comparison */ const void *pKey2, int nKey2, /* Right side of comparison */ int *pRes, /* OUT: Result of comparison */ UnpackedRecord *r2 /* Space to hold the unpacked Key2 record */ ){ KeyInfo *pKeyInfo = pCsr->pKeyInfo; int i; if( pKey2 ){ assert( r2!=0 ); sqlite3VdbeRecordUnpack(pKeyInfo, nKey2, pKey2, r2); } if( bOmitRowid ){ r2->nField = pKeyInfo->nField; assert( r2->nField>0 ); for(i=0; i<r2->nField; i++){ |
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441 442 443 444 445 446 447 | if( p1->pFile==0 ){ iRes = i2; }else if( p2->pFile==0 ){ iRes = i1; }else{ int res; | < | > | 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 | if( p1->pFile==0 ){ iRes = i2; }else if( p2->pFile==0 ){ iRes = i1; }else{ int res; vdbeSorterCompare( pCsr, 0, p1->aKey, p1->nKey, p2->aKey, p2->nKey, &res, pSorter->pUnpacked ); if( res<=0 ){ iRes = i1; }else{ iRes = i2; } } |
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543 544 545 546 547 548 549 | ** Merge the two sorted lists p1 and p2 into a single list. ** Set *ppOut to the head of the new list. */ static void vdbeSorterMerge( const VdbeCursor *pCsr, /* For pKeyInfo */ SorterRecord *p1, /* First list to merge */ SorterRecord *p2, /* Second list to merge */ | | > | > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > | < > > > > > > > > | | | | > | < | < < | < > | | | | | > > | | > > | | | | | 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 | ** Merge the two sorted lists p1 and p2 into a single list. ** Set *ppOut to the head of the new list. */ static void vdbeSorterMerge( const VdbeCursor *pCsr, /* For pKeyInfo */ SorterRecord *p1, /* First list to merge */ SorterRecord *p2, /* Second list to merge */ SorterRecord **ppOut, /* OUT: Head of merged list */ UnpackedRecord *pUnpacked /* Space to hold an unpacked record */ ){ SorterRecord *pFinal = 0; SorterRecord **pp = &pFinal; void *pVal2 = p2 ? p2->pVal : 0; while( p1 && p2 ){ int res; vdbeSorterCompare(pCsr, 0, p1->pVal, p1->nVal, pVal2, p2->nVal, &res, pUnpacked); if( res<=0 ){ *pp = p1; pp = &p1->pNext; p1 = p1->pNext; pVal2 = 0; }else{ *pp = p2; pp = &p2->pNext; p2 = p2->pNext; if( p2==0 ) break; pVal2 = p2->pVal; } } *pp = p1 ? p1 : p2; *ppOut = pFinal; } /* ** Background sorting task */ typedef struct SortTask { SorterRecord *pList; /* List of elements to be sorted */ const VdbeCursor *pCsr; /* Cursor. Needed for pCur->pKeyInfo */ UnpackedRecord *pUnpacked; /* Space to hold an unpacked key */ SorterRecord **apSlot; /* Temp memory for the merge sort */ } SortTask; /* ** Do a sort in a background thread */ void *vdbeSorterBackgroundSort(SortTask *pTask){ SorterRecord *p = pTask->pList; SorterRecord **a = pTask->apSlot; int i; for(i=0; i<64; i++) a[i] = 0; while( p ){ SorterRecord *pNext = p->pNext; p->pNext = 0; for(i=0; a[i]; i++){ if( a[i]==0 ) break; vdbeSorterMerge(pTask->pCsr, a[i], p, &p, pTask->pUnpacked); a[i] = 0; } a[i] = p; p = pNext; } p = 0; for(i=0; i<64; i++){ vdbeSorterMerge(pTask->pCsr, a[i], p, &p, pTask->pUnpacked); } pTask->pList = p; return p; } /* ** Divide a linked list of SorterRecord objects into two separate ** linked lists */ static void vdbeSorterDivideList( SorterRecord *pIn, /* The list to be divided */ SorterRecord **ppOut1, /* Write the first list here */ SorterRecord **ppOut2 /* Write the second list here */ ){ int i = 0; *ppOut1 = *ppOut2 = 0; while( pIn ){ SorterRecord *pNext = pIn->pNext; pIn->pNext = 0; if( i & 1 ){ *ppOut1 = pIn; ppOut1 = &pIn->pNext; }else{ *ppOut2 = pIn; ppOut2 = &pIn->pNext; } i++; pIn = pNext; } } /* ** Sort the linked list of records headed at pCsr->pRecord. Return SQLITE_OK ** if successful, or an SQLite error code (i.e. SQLITE_NOMEM) if an error ** occurs. */ static int vdbeSorterSort(const VdbeCursor *pCsr){ int rc; SorterRecord *p; VdbeSorter *pSorter = pCsr->pSorter; char *pDummy = 0; int nByteA, nByteB; SortTask aTask[2]; SQLiteThread *pThread; nByteA = 64*sizeof(SorterRecord*); nByteB = ROUND8(sizeof(UnpackedRecord)); nByteB += sizeof(Mem)*(pCsr->pKeyInfo->nField+1); aTask[0].apSlot = (SorterRecord **)sqlite3MallocZero(2*(nByteA + nByteB)); if( !aTask[0].apSlot ){ return SQLITE_NOMEM; } aTask[0].pCsr = pCsr; aTask[0].pUnpacked = sqlite3VdbeAllocUnpackedRecord(pCsr->pKeyInfo, (char*)&aTask[0].apSlot[64], nByteB, &pDummy); assert( pDummy==0 ); aTask[1].apSlot = (nByteA+nByteB)+(char*)aTask[0].apSlot; aTask[1].pCsr = pCsr; aTask[1].pUnpacked = sqlite3VdbeAllocUnpackedRecord(pCsr->pKeyInfo, (char*)&aTask[1].apSlot[64], nByteB, &pDummy); assert( pDummy==0 ); vdbeSorterDivideList(pSorter->pRecord, &aTask[0].pList, &aTask[1].pList); rc = sqlite3ThreadCreate(&pThread, (void*(*)(void*))vdbeSorterBackgroundSort, &aTask[0]); vdbeSorterBackgroundSort(&aTask[1]); if( rc==SQLITE_NOMEM ){ vdbeSorterBackgroundSort(&aTask[0]); }else{ rc = sqlite3ThreadJoin(pThread, &pDummy); } vdbeSorterMerge(pCsr, aTask[0].pList, aTask[1].pList, &pSorter->pRecord, aTask[0].pUnpacked); sqlite3_free(aTask[0].apSlot); return rc; } /* ** Initialize a file-writer object. */ static void fileWriterInit( sqlite3 *db, /* Database (for malloc) */ |
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715 716 717 718 719 720 721 722 723 724 725 726 727 728 | VdbeSorter *pSorter = pCsr->pSorter; FileWriter writer; memset(&writer, 0, sizeof(FileWriter)); if( pSorter->nInMemory==0 ){ assert( pSorter->pRecord==0 ); return rc; } rc = vdbeSorterSort(pCsr); /* If the first temporary PMA file has not been opened, open it now. */ if( rc==SQLITE_OK && pSorter->pTemp1==0 ){ | > | 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 | VdbeSorter *pSorter = pCsr->pSorter; FileWriter writer; memset(&writer, 0, sizeof(FileWriter)); if( pSorter->nInMemory==0 ){ assert( pSorter->pRecord==0 ); assert( pSorter->nRecord==0 ); return rc; } rc = vdbeSorterSort(pCsr); /* If the first temporary PMA file has not been opened, open it now. */ if( rc==SQLITE_OK && pSorter->pTemp1==0 ){ |
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741 742 743 744 745 746 747 | fileWriterWriteVarint(&writer, pSorter->nInMemory); for(p=pSorter->pRecord; p; p=pNext){ pNext = p->pNext; fileWriterWriteVarint(&writer, p->nVal); fileWriterWrite(&writer, p->pVal, p->nVal); sqlite3DbFree(db, p); } | | > | 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 | fileWriterWriteVarint(&writer, pSorter->nInMemory); for(p=pSorter->pRecord; p; p=pNext){ pNext = p->pNext; fileWriterWriteVarint(&writer, p->nVal); fileWriterWrite(&writer, p->pVal, p->nVal); sqlite3DbFree(db, p); } pSorter->pRecord = 0; pSorter->nRecord = 0; rc = fileWriterFinish(db, &writer, &pSorter->iWriteOff); } return rc; } /* |
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772 773 774 775 776 777 778 779 780 781 782 783 784 785 | rc = SQLITE_NOMEM; }else{ pNew->pVal = (void *)&pNew[1]; memcpy(pNew->pVal, pVal->z, pVal->n); pNew->nVal = pVal->n; pNew->pNext = pSorter->pRecord; pSorter->pRecord = pNew; } /* See if the contents of the sorter should now be written out. They ** are written out when either of the following are true: ** ** * The total memory allocated for the in-memory list is greater ** than (page-size * cache-size), or | > | 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 | rc = SQLITE_NOMEM; }else{ pNew->pVal = (void *)&pNew[1]; memcpy(pNew->pVal, pVal->z, pVal->n); pNew->nVal = pVal->n; pNew->pNext = pSorter->pRecord; pSorter->pRecord = pNew; pSorter->nRecord++; } /* See if the contents of the sorter should now be written out. They ** are written out when either of the following are true: ** ** * The total memory allocated for the in-memory list is greater ** than (page-size * cache-size), or |
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961 962 963 964 965 966 967 968 969 970 971 972 973 974 | rc = vdbeSorterDoCompare(pCsr, i); } *pbEof = (pSorter->aIter[pSorter->aTree[1]].pFile==0); }else{ SorterRecord *pFree = pSorter->pRecord; pSorter->pRecord = pFree->pNext; pFree->pNext = 0; vdbeSorterRecordFree(db, pFree); *pbEof = !pSorter->pRecord; rc = SQLITE_OK; } return rc; } | > | 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 | rc = vdbeSorterDoCompare(pCsr, i); } *pbEof = (pSorter->aIter[pSorter->aTree[1]].pFile==0); }else{ SorterRecord *pFree = pSorter->pRecord; pSorter->pRecord = pFree->pNext; pSorter->nRecord--; pFree->pNext = 0; vdbeSorterRecordFree(db, pFree); *pbEof = !pSorter->pRecord; rc = SQLITE_OK; } return rc; } |
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1027 1028 1029 1030 1031 1032 1033 | Mem *pVal, /* Value to compare to current sorter key */ int *pRes /* OUT: Result of comparison */ ){ VdbeSorter *pSorter = pCsr->pSorter; void *pKey; int nKey; /* Sorter key to compare pVal with */ pKey = vdbeSorterRowkey(pSorter, &nKey); | | > | 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 | Mem *pVal, /* Value to compare to current sorter key */ int *pRes /* OUT: Result of comparison */ ){ VdbeSorter *pSorter = pCsr->pSorter; void *pKey; int nKey; /* Sorter key to compare pVal with */ pKey = vdbeSorterRowkey(pSorter, &nKey); vdbeSorterCompare(pCsr, 1, pVal->z, pVal->n, pKey, nKey, pRes, pSorter->pUnpacked); return SQLITE_OK; } #endif /* #ifndef SQLITE_OMIT_MERGE_SORT */ |