From: drh <drh@noemail.net>
Date: Fri, 3 Jun 2011 23:28:33 +0000 (+0000)
Subject: Performance improvements on memory copies inside of btree by moving 2 bytes
X-Git-Tag: version-3.7.7~70
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=61d2fe955c2af8a24ab3829d143c8f9fd6324319;p=thirdparty%2Fsqlite.git

Performance improvements on memory copies inside of btree by moving 2 bytes
at a time instead of just 1 byte at a time.

FossilOrigin-Name: 897f56a158ebe62758c9998e4941ae046c75fb99
---

diff --git a/manifest b/manifest
index 014b8a5783..7f9a970797 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Performance\senhancement\sto\sthe\sblob-literal\stokenizer.
-D 2011-06-03T21:34:45.326
+C Performance\simprovements\son\smemory\scopies\sinside\sof\sbtree\sby\smoving\s2\sbytes\nat\sa\stime\sinstead\sof\sjust\s1\sbyte\sat\sa\stime.
+D 2011-06-03T23:28:33.011
 F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
 F Makefile.in 11dcc00a8d0e5202def00e81732784fb0cc4fe1d
 F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
@@ -122,7 +122,7 @@ F src/auth.c 523da7fb4979469955d822ff9298352d6b31de34
 F src/backup.c 986c15232757f2873dff35ee3b35cbf935fc573c
 F src/bitvec.c af50f1c8c0ff54d6bdb7a80e2fceca5a93670bef
 F src/btmutex.c 976f45a12e37293e32cae0281b15a21d48a8aaa7
-F src/btree.c 12aa3b71359c888984223cb2bcf691cf2d7753ae
+F src/btree.c 9f214af284fae1e96f12989dcc4d26f247b502fc
 F src/btree.h f5d775cd6cfc7ac32a2535b70e8d2af48ef5f2ce
 F src/btreeInt.h 67978c014fa4f7cc874032dd3aacadd8db656bc3
 F src/build.c 5a428625d21ad409514afb40ad083bee25dd957a
@@ -942,7 +942,7 @@ F tool/split-sqlite3c.tcl d9be87f1c340285a3e081eb19b4a247981ed290c
 F tool/symbols.sh bc2a3709940d47c8ac8e0a1fdf17ec801f015a00
 F tool/vdbe-compress.tcl d70ea6d8a19e3571d7ab8c9b75cba86d1173ff0f
 F tool/warnings.sh 347d974d143cf132f953b565fbc03026f19fcb4d
-P 957b2ab67c6185f0e1062593d237de5c434a38bf
-R bd36ddd3c30f1348cf18f2599b20bbca
+P 61aa2031f1c5ae05e31077588a55194a9546262a
+R ee8453a74951d0e43529f6f62862f77e
 U drh
-Z fe6a860af7a1658c61a1531782a69559
+Z eb5472e3af1761c7727508ef6d936f22
diff --git a/manifest.uuid b/manifest.uuid
index 01e044ed3e..246d28ad64 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-61aa2031f1c5ae05e31077588a55194a9546262a
\ No newline at end of file
+897f56a158ebe62758c9998e4941ae046c75fb99
\ No newline at end of file
diff --git a/src/btree.c b/src/btree.c
index 9e9677cc42..ece4602159 100644
--- a/src/btree.c
+++ b/src/btree.c
@@ -5422,8 +5422,7 @@ static void dropCell(MemPage *pPage, int idx, int sz, int *pRC){
   }
   endPtr = &data[pPage->cellOffset + 2*pPage->nCell - 2];
   while( ptr<endPtr ){
-    ptr[0] = ptr[2];
-    ptr[1] = ptr[3];
+    *(u16*)ptr = *(u16*)&ptr[2];
     ptr += 2;
   }
   pPage->nCell--;
@@ -5464,6 +5463,7 @@ static void insertCell(
   int cellOffset;   /* Address of first cell pointer in data[] */
   u8 *data;         /* The content of the whole page */
   u8 *ptr;          /* Used for moving information around in data[] */
+  u8 *endPtr;       /* End of the loop */
 
   int nSkip = (iChild ? 4 : 0);
 
@@ -5514,9 +5514,11 @@ static void insertCell(
     if( iChild ){
       put4byte(&data[idx], iChild);
     }
-    for(j=end, ptr=&data[j]; j>ins; j-=2, ptr-=2){
-      ptr[0] = ptr[-2];
-      ptr[1] = ptr[-1];
+    ptr = &data[end];
+    endPtr = &data[ins];
+    while( ptr>endPtr ){
+      *(u16*)ptr = *(u16*)&ptr[-2];
+      ptr -= 2;
     }
     put2byte(&data[ins], idx);
     put2byte(&data[pPage->hdrOffset+3], pPage->nCell);
@@ -5561,10 +5563,11 @@ static void assemblePage(
   pCellptr = &data[pPage->cellOffset + nCell*2];
   cellbody = nUsable;
   for(i=nCell-1; i>=0; i--){
+    u16 sz = aSize[i];
     pCellptr -= 2;
-    cellbody -= aSize[i];
+    cellbody -= sz;
     put2byte(pCellptr, cellbody);
-    memcpy(&data[cellbody], apCell[i], aSize[i]);
+    memcpy(&data[cellbody], apCell[i], sz);
   }
   put2byte(&data[hdr+3], nCell);
   put2byte(&data[hdr+5], cellbody);