include newest lite weight latch code.

diff --git a/btree2t.c b/btree2t.c
index 54be57f62c0cfa84f369fc30f9bf67f8e565f065..bb0e50f06a7ac976440afd177e5b75263624e7b8 100644 (file)
--- a/btree2t.c
+++ b/btree2t.c
@@ -1,6 +1,6 @@
-// btree version 2t
+// btree version 2t  sched_yield version of spinlocks
 //     with reworked bt_deletekey code
-// 25 FEB 2014
+// 12 MAR 2014
 
 // author: karl malbrain, malbrain@cal.berkeley.edu
 
@@ -91,12 +91,16 @@ typedef enum{
 // grant write lock when share == 0
 
 volatile typedef struct {
-       unsigned char mutex[1];
-       unsigned char exclusive:1;
-       unsigned char pending:1;
-       ushort share;
+       ushort exclusive:1;
+       ushort pending:1;
+       ushort share:14;
 } BtSpinLatch;
 
+#define XCL 1
+#define PEND 2
+#define BOTH 3
+#define SHARE 4
+
 //  hash table entries
 
 typedef struct {
@@ -358,7 +362,7 @@ BtKey ptr;
        return bt->err = err;
 }
 
-//     Latch Manager
+//     Spin Latch Manager
 
 //     wait until write lock mode is clear
 //     and add 1 to the share count
@@ -368,28 +372,20 @@ void bt_spinreadlock(BtSpinLatch *latch)
 ushort prev;
 
   do {
-       //      obtain latch mutex
 #ifdef unix
-       if( __sync_lock_test_and_set(latch->mutex, 1) )
-               continue;
+       prev = __sync_fetch_and_add ((ushort *)latch, SHARE);
 #else
-       if( _InterlockedExchange8(latch->mutex, 1) )
-               continue;
+       prev = _InterlockedExchangeAdd16((ushort *)latch, SHARE);
 #endif
        //  see if exclusive request is granted or pending
 
-       if( prev = !(latch->exclusive | latch->pending) )
-               latch->share++;
-
+       if( !(prev & BOTH) )
+               return;
 #ifdef unix
-       *latch->mutex = 0;
+       prev = __sync_fetch_and_add ((ushort *)latch, -SHARE);
 #else
-       _InterlockedExchange8(latch->mutex, 0);
+       prev = _InterlockedExchangeAdd16((ushort *)latch, -SHARE);
 #endif
-
-       if( prev )
-               return;
-
 #ifdef  unix
   } while( sched_yield(), 1 );
 #else
@@ -401,27 +397,23 @@ ushort prev;
 
 void bt_spinwritelock(BtSpinLatch *latch)
 {
-uint prev;
+ushort prev;
 
   do {
 #ifdef  unix
-       if( __sync_lock_test_and_set(latch->mutex, 1) )
-               continue;
+       prev = __sync_fetch_and_or((ushort *)latch, PEND | XCL);
 #else
-       if( _InterlockedExchange8(latch->mutex, 1) )
-               continue;
+       prev = _InterlockedOr16((ushort *)latch, PEND | XCL);
 #endif
-       if( prev = !(latch->share | latch->exclusive) )
-               latch->exclusive = 1, latch->pending = 0;
-       else
-               latch->pending = 1;
+       if( !(prev & XCL) )
+         if( !(prev & ~BOTH) )
+               return;
+         else
 #ifdef unix
-       *latch->mutex = 0;
+               __sync_fetch_and_and ((ushort *)latch, ~XCL);
 #else
-       _InterlockedExchange8(latch->mutex, 0);
+               _InterlockedAnd16((ushort *)latch, ~XCL);
 #endif
-       if( prev )
-               return;
 #ifdef  unix
   } while( sched_yield(), 1 );
 #else
@@ -436,26 +428,25 @@ uint prev;
 
 int bt_spinwritetry(BtSpinLatch *latch)
 {
-uint prev;
+ushort prev;
 
-#ifdef unix
-       if( __sync_lock_test_and_set(latch->mutex, 1) )
-               return 0;
+#ifdef  unix
+       prev = __sync_fetch_and_or((ushort *)latch, XCL);
 #else
-       if( _InterlockedExchange8(latch->mutex, 1) )
-               return 0;
+       prev = _InterlockedOr16((ushort *)latch, XCL);
 #endif
        //      take write access if all bits are clear
 
-       if( prev = !(latch->exclusive | latch->share) )
-               latch->exclusive = 1;
-
+       if( !(prev & XCL) )
+         if( !(prev & ~BOTH) )
+               return 1;
+         else
 #ifdef unix
-       *latch->mutex = 0;
+               __sync_fetch_and_and ((ushort *)latch, ~XCL);
 #else
-       _InterlockedExchange8(latch->mutex, 0);
+               _InterlockedAnd16((ushort *)latch, ~XCL);
 #endif
-       return prev;
+       return 0;
 }
 
 //     clear write mode
@@ -463,17 +454,9 @@ uint prev;
 void bt_spinreleasewrite(BtSpinLatch *latch)
 {
 #ifdef unix
-       while( __sync_lock_test_and_set(latch->mutex, 1) )
-               sched_yield();
-#else
-       while( _InterlockedExchange8(latch->mutex, 1) )
-               SwitchToThread();
-#endif
-       latch->exclusive = 0;
-#ifdef unix
-       *latch->mutex = 0;
+       __sync_fetch_and_and((ushort *)latch, ~BOTH);
 #else
-       _InterlockedExchange8(latch->mutex, 0);
+       _InterlockedAnd16((ushort *)latch, ~BOTH);
 #endif
 }
 
@@ -482,17 +465,9 @@ void bt_spinreleasewrite(BtSpinLatch *latch)
 void bt_spinreleaseread(BtSpinLatch *latch)
 {
 #ifdef unix
-       while( __sync_lock_test_and_set(latch->mutex, 1) )
-               sched_yield();
-#else
-       while( _InterlockedExchange8(latch->mutex, 1) )
-               SwitchToThread();
-#endif
-       latch->share--;
-#ifdef unix
-       *latch->mutex = 0;
+       __sync_fetch_and_add((ushort *)latch, -SHARE);
 #else
-       _InterlockedExchange8(latch->mutex, 0);
+       _InterlockedExchangeAdd16((ushort *)latch, -SHARE);
 #endif
 }
 
@@ -728,6 +703,7 @@ int flag;
 #ifndef unix
 SYSTEM_INFO sysinfo[1];
 OVERLAPPED ovl[1];
+uint len, flags;
 #else
 struct flock lock[1];
 #endif
@@ -2133,6 +2109,8 @@ uint cnt = 0;
 BtKey ptr;
 
 #ifdef unix
+       posix_fadvise( bt->idx, 0, 0, POSIX_FADV_SEQUENTIAL);
+#endif
        if( *(ushort *)(bt->latchmgr->lock) )
                fprintf(stderr, "Alloc page locked\n");
        *(ushort *)(bt->latchmgr->lock) = 0;
@@ -2179,7 +2157,20 @@ BtKey ptr;
        page_no = LEAF_page;
 
        while( page_no < bt_getid(bt->latchmgr->alloc->right) ) {
-               pread (bt->idx, bt->frame, bt->page_size, page_no << bt->page_bits);
+       off64_t off = page_no << bt->page_bits;
+#ifdef unix
+               pread (bt->idx, bt->frame, bt->page_size, off);
+#else
+               DWORD amt[1];
+
+                 SetFilePointer (bt->idx, (long)off, (long*)(&off)+1, FILE_BEGIN);
+
+                 if( !ReadFile(bt->idx, bt->frame, bt->page_size, amt, NULL))
+                       fprintf(stderr, "page %.8x unable to read\n", page_no);
+
+                 if( *amt <  bt->page_size )
+                       fprintf(stderr, "page %.8x unable to read\n", page_no);
+#endif
                if( !bt->frame->free ) {
                 for( idx = 0; idx++ < bt->frame->cnt - 1; ) {
                  ptr = keyptr(bt->frame, idx+1);
@@ -2195,7 +2186,6 @@ BtKey ptr;
                page_no = next;
        }
        return cnt - 1;
-#endif
 }
 
 #ifndef unix