initial commit

6 files changed, 301 insertions, 0 deletions

diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..63e4a7c
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,21 @@
+
+
+CC     = gcc
+STD    = _GNU_SOURCE
+CFLAGS = -DDEBUG
+BIN    = cas_test lock_free_queue_test
+
+.c.o:
+	$(CC) -c -Wall -I. $(CFLAGS) -D$(STD) $<
+
+all: $(BIN)
+
+cas_test: cas_test.o
+	$(CC) cas_test.o -o cas_test
+
+lock_free_queue_test: lock_free_queue.o lock_free_queue_test.o
+	$(CC) lock_free_queue.o lock_free_queue_test.o -o lock_free_queue_test
+
+clean:
+	rm -f *~ *.o core $(BIN)
+
diff --git a/cas.h b/cas.h
new file mode 100644
index 0000000..b04f7c3
--- /dev/null
+++ b/cas.h
@@ -0,0 +1,40 @@
+/*
+ * File     : cas.c
+ * Author   : Jérémy Zurcher  <jeremy@asynk.ch>
+ * Date     : 01/11/09 
+ * License  :
+ *
+ *  Permission is hereby granted, free of charge, to any person obtaining
+ *  a copy of this software and associated documentation files (the
+ *  "Software"), to deal in the Software without restriction, including
+ *  without limitation the rights to use, copy, modify, merge, publish,
+ *  distribute, sublicense, and/or sell copies of the Software, and to
+ *  permit persons to whom the Software is furnished to do so, subject to
+ *  the following conditions:
+ *  
+ *  The above copyright notice and this permission notice shall be
+ *  included in all copies or substantial portions of the Software.
+ *  
+ *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ *  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ *  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ *  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ *  LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ *  OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ *  WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ */
+
+/* CMPXCHG8B m64   Compare EDX:EAX with m64. If equal, set ZF and load ECX:EBX into m64. Else, clear ZF and load m64 into EDX:EAX. */
+static inline unsigned int compare_and_swap(volatile unsigned long long *mem,
+                                            volatile unsigned long long old,
+                                            volatile unsigned long long new) {
+    char result;
+    __asm__ __volatile__("lock; cmpxchg8b %0; setz %1;"
+            : "=m"(*mem), "=q"(result)
+            : "m"(*mem), "d" ((unsigned long)(old>>32)), "a" ((unsigned long)old),
+            "c" ((unsigned long)(new>>32)), "b" ((unsigned long)new)
+            : "memory");
+    return (int)result;
+}
+
diff --git a/cas_test.c b/cas_test.c
new file mode 100644
index 0000000..a2b92a6
--- /dev/null
+++ b/cas_test.c
@@ -0,0 +1,62 @@
+/*
+ * File     : atomic.c
+ * Author   : Jérémy Zurcher  <jeremy@asynk.ch>
+ * Date     : 01/11/09 
+ * License  :
+ *
+ *  Permission is hereby granted, free of charge, to any person obtaining
+ *  a copy of this software and associated documentation files (the
+ *  "Software"), to deal in the Software without restriction, including
+ *  without limitation the rights to use, copy, modify, merge, publish,
+ *  distribute, sublicense, and/or sell copies of the Software, and to
+ *  permit persons to whom the Software is furnished to do so, subject to
+ *  the following conditions:
+ *  
+ *  The above copyright notice and this permission notice shall be
+ *  included in all copies or substantial portions of the Software.
+ *  
+ *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ *  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ *  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ *  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ *  LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ *  OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ *  WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ */
+
+#include <stdio.h>
+#include "cas.h"
+
+#define MAKE_LONG_LONG(lo, hi)		((hi)<<32)+(lo)
+
+typedef union pointer {
+    struct {
+        volatile void *ptr;
+        volatile unsigned int count;
+    } split;
+    volatile unsigned long long concat;
+} pointer_t;
+
+int main( int argc, char*argv[], char*env[] ) {
+    int ret;
+
+    pointer_t mem, old, new;
+    
+    mem.split.count = 0;
+    old.split.count = 6;
+    new.split.count = 666;
+    mem.split.ptr = (void*)&argc;
+    old.split.ptr = (void*)&argc;
+    new.split.ptr = (void*)&argv;
+
+    ret = compare_and_swap(&mem.concat, old.concat, new.concat);
+    printf("ret %d -> (%d,%X)\n", ret, mem.split.count, (unsigned int)mem.split.ptr);
+
+    mem.split.count=6;
+    ret = compare_and_swap(&mem.concat, old.concat, new.concat);
+    printf("ret %d -> (%d,%X)\n", ret, mem.split.count, (unsigned int)mem.split.ptr);
+
+    return 0;
+}
+
diff --git a/lock_free_queue.c b/lock_free_queue.c
new file mode 100644
index 0000000..217fb0b
--- /dev/null
+++ b/lock_free_queue.c
@@ -0,0 +1,88 @@
+/*
+ * File     : lock_free_queue.c
+ * Author   : Jérémy Zurcher  <jeremy@asynk.ch>
+ * Date     : 01/11/09 
+ * License  : stolen from http://www.cs.rochester.edu/~scott/papers/1996_PODC_queues.pdf
+ */
+
+#include "stdlib.h"
+#include "cas.h"
+#include "lock_free_queue.h"
+#ifdef DEBUG
+#include "stdio.h"
+#endif
+
+void init( lfq_t *q ) {
+    node_t *node = (node_t*)malloc(sizeof(node_t));
+    node->next.split.ptr = NULL;
+    node->next.split.count = 0;
+    q->head.split.ptr = q->tail.split.ptr = node;
+    q->head.split.count = q->tail.split.count = 0;
+}
+
+void enqueue( lfq_t *q, void *data ) {
+    node_t *node;
+    pointer_t tail;
+    pointer_t next;
+    pointer_t tmp;
+
+    node = (node_t*)malloc(sizeof(node_t));
+    node->data = data;
+    node->next.split.ptr = NULL;
+    /* node->next.split.count = 0; */
+    for(;;) {
+        tail.concat = q->tail.concat;                   /* copy tail pointer */
+        next.concat = tail.split.ptr->next.concat;      /* copy next pointer */
+        if (tail.concat == q->tail.concat) {            /* tail is still consistent */
+            if (next.split.ptr == NULL) {               /* next is still the last node */
+                /* if tail->next is the same as next, link node at the end of the list */
+                tmp.split.ptr = node;
+                tmp.split.count = next.split.count+1;
+                if ( compare_and_swap( &tail.split.ptr->next.concat, next.concat, tmp.concat ) ) break;
+            } else {
+                /* try to swing tail to the next node, if q-> tail is still tail => next is ok */
+                tmp.split.ptr = next.split.ptr;
+                tmp.split.count = tail.split.count+1;
+                compare_and_swap( &q->tail.concat, tail.concat, tmp.concat );
+            }
+        }
+    }
+    /* try to swing tail to the next node, may have been done by a concurrent push */
+    tmp.split.ptr = node;
+    tmp.split.count = tail.split.count+1;
+    compare_and_swap( &q->tail.concat, tail.concat, tmp.concat );
+}
+
+void* dequeue( lfq_t *q ) {
+    void *data;
+    pointer_t head;
+    pointer_t tail;
+    node_t *next;
+    pointer_t tmp;
+    
+    for(;;) {
+        head.concat = q->head.concat;
+        tail.concat = q->tail.concat;
+        next = (node_t *)head.split.ptr;
+        if (head.concat == q->head.concat) {
+            if (head.split.ptr == tail.split.ptr) {     /* still consistent */
+                if (next->next.split.ptr == NULL) {     /* queue empty */
+                    return NULL;
+                }
+                /* new node has been linked, but tail is behind, should advance it */
+                tmp.split.ptr = next->next.split.ptr;
+                tmp.split.count = tail.split.count+1;
+                compare_and_swap( &q->tail.concat, tail.concat, tmp.concat );
+            } else {
+                data = next->data;
+                /* try to swing head to the next node */
+                tmp.split.ptr = next->next.split.ptr;
+                tmp.split.count = head.split.count+1;
+                if( compare_and_swap( &q->head.concat, head.concat, tmp.concat ) ) break;
+            }
+        }
+    }
+    free((void*)head.split.ptr);
+    return data;
+}
+
diff --git a/lock_free_queue.h b/lock_free_queue.h
new file mode 100644
index 0000000..ac8a859
--- /dev/null
+++ b/lock_free_queue.h
@@ -0,0 +1,31 @@
+/*
+ * File     : lock_free_queue.c
+ * Author   : Jérémy Zurcher  <jeremy@asynk.ch>
+ * Date     : 01/11/09 
+ * License  : stolen from http://www.cs.rochester.edu/~scott/papers/1996_PODC_queues.pdf
+ */
+
+struct node;
+
+typedef union pointer {
+    struct {
+        volatile struct node *ptr;
+        volatile unsigned int count;
+    } split;
+    volatile unsigned long long concat;
+} pointer_t;
+
+typedef struct node {
+    void *data;
+    pointer_t next;
+} node_t;
+
+typedef struct queue {
+    pointer_t head;
+    pointer_t tail;
+} lfq_t;
+
+void init( lfq_t *q );
+void enqueue( lfq_t *q, void *data );
+void* dequeue( lfq_t *q );
+
diff --git a/lock_free_queue_test.c b/lock_free_queue_test.c
new file mode 100644
index 0000000..64544eb
--- /dev/null
+++ b/lock_free_queue_test.c
@@ -0,0 +1,59 @@
+/*
+ * File     : lock_free_queue.c
+ * Author   : Jérémy Zurcher  <jeremy@asynk.ch>
+ * Date     : 01/11/09 
+ * License  :
+ *
+ *  Permission is hereby granted, free of charge, to any person obtaining
+ *  a copy of this software and associated documentation files (the
+ *  "Software"), to deal in the Software without restriction, including
+ *  without limitation the rights to use, copy, modify, merge, publish,
+ *  distribute, sublicense, and/or sell copies of the Software, and to
+ *  permit persons to whom the Software is furnished to do so, subject to
+ *  the following conditions:
+ *  
+ *  The above copyright notice and this permission notice shall be
+ *  included in all copies or substantial portions of the Software.
+ *  
+ *  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ *  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ *  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ *  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+ *  LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+ *  OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ *  WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ */
+
+#include "stdio.h"
+#include "stdlib.h"
+#include "lock_free_queue.h"
+
+int main(int argc, char *argv[]) {
+    lfq_t q;
+    node_t *it;
+    int data[10];
+    int i;
+
+    for(i=0; i<10; i++) data[i]=i;
+    for(i=0; i<10; i++) printf("data[i] :%d (%X)\n",data[i],(unsigned int)&data[i]);
+    
+    init( &q);
+    for(i=0; i<10; i++) enqueue( &q, (void*)&data[i] );
+
+    it = (node_t*)q.head.split.ptr;
+    while(it!=NULL) {
+        if(it->data>0)printf("data : %X %d\n",(unsigned int)it->data,*((int*)it->data));
+        it = (node_t*)it->next.split.ptr;
+    }
+    
+    for(i=0; i<5; i++) printf("unqueue %X\n",(unsigned int)dequeue( &q ));
+    it = (node_t*)q.head.split.ptr;
+    while(it!=NULL) {
+        if(it->data>0)printf("data : %X %d\n",(unsigned int)it->data,*((int*)it->data));
+        it = (node_t*)it->next.split.ptr;
+    }
+
+
+    return EXIT_SUCCESS;
+}