diff --git a/shctx.c b/shctx.c
index 0bafb54..ca0bb3c 100644
--- a/shctx.c
+++ b/shctx.c
@@ -48,6 +48,7 @@ static void (*shared_session_new_cbk)(unsigned char *session, unsigned int sessi
 
 /* Lock functions */
 #ifdef USE_SYSCALL_FUTEX
+#if defined (__i586__) || defined (__x86_64__)
 static inline unsigned int xchg(unsigned int *ptr, unsigned int x)
 {
 	__asm volatile("lock xchgl %0,%1"
@@ -68,10 +69,10 @@ static inline unsigned int cmpxchg(unsigned int *ptr, unsigned int old, unsigned
 	return ret;
 }
 
-static inline unsigned char atomic_inc(unsigned int *ptr)
+static inline unsigned char atomic_dec(unsigned int *ptr)
 {
 	unsigned char ret;
-	__asm volatile("lock incl %0\n"
+	__asm volatile("lock decl %0\n"
 		     "setne %1\n"
 		     : "+m" (*ptr), "=qm" (ret)
 		     :
@@ -79,17 +80,24 @@ static inline unsigned char atomic_inc(unsigned int *ptr)
 	return ret;
 }
 
+#else /* if no x86_64 or i586 arch: use less optimized gcc >= 4.1 built-ins */
+static inline unsigned int xchg(unsigned int *ptr, unsigned int x)
+{
+	return __sync_lock_test_and_set(ptr, x);
+}
+
+static inline unsigned int cmpxchg(unsigned int *ptr, unsigned int old, unsigned int new)
+{
+	return __sync_val_compare_and_swap(ptr, old, new);
+}
+
 static inline unsigned char atomic_dec(unsigned int *ptr)
 {
-	unsigned char ret;
-	__asm volatile("lock decl %0\n"
-		     "setne %1\n"
-		     : "+m" (*ptr), "=qm" (ret)
-		     :
-		     : "memory");
-	return ret;
+	return __sync_sub_and_fetch(ptr, 1) ? 1 : 0;
 }
 
+#endif
+
 static inline void shared_context_lock(void)
 {
 	unsigned int x;
@@ -164,11 +172,11 @@ static inline void shared_context_unlock(void)
 
 /* SSL callback used on new session creation */
 int shctx_new_cb(SSL *ssl, SSL_SESSION *sess) {
-	(void)ssl;
 	struct shared_session *shsess;
 	unsigned char *data,*p;
 	unsigned int data_len;
 	unsigned char encsess[SHSESS_MAX_ENCODED_LEN];
+	(void)ssl;
 
 	/* check if session reserved size in aligned buffer is large enougth for the ASN1 encode session */
 	data_len=i2d_SSL_SESSION(sess, NULL);
@@ -216,13 +224,13 @@ int shctx_new_cb(SSL *ssl, SSL_SESSION *sess) {
 
 /* SSL callback used on lookup an existing session cause none found in internal cache */
 SSL_SESSION *shctx_get_cb(SSL *ssl, unsigned char *key, int key_len, int *do_copy) {
-	(void)ssl;
 	struct shared_session *shsess;
 	unsigned char data[SHSESS_MAX_DATA_LEN], *p;
 	unsigned char tmpkey[SSL_MAX_SSL_SESSION_ID_LENGTH];
 	unsigned int data_len;
 	long cdate;
 	SSL_SESSION *sess;
+	(void)ssl;
 
         /* allow the session to be freed automatically by openssl */
 	*do_copy = 0;
@@ -269,10 +277,10 @@ SSL_SESSION *shctx_get_cb(SSL *ssl, unsigned char *key, int key_len, int *do_cop
 
 /* SSL callback used to signal session is no more used in internal cache */
 void shctx_remove_cb(SSL_CTX *ctx, SSL_SESSION *sess) {
-	(void)ctx;
 	struct shared_session *shsess;
 	unsigned char tmpkey[SSL_MAX_SSL_SESSION_ID_LENGTH];
 	unsigned char *key = sess->session_id;
+	(void)ctx;
 
 	/* tree key is zeros padded sessionid */
 	if ( sess->session_id_length < SSL_MAX_SSL_SESSION_ID_LENGTH ) {
@@ -333,64 +341,80 @@ void shsess_set_new_cbk(void (*func)(unsigned char *, unsigned int, long)) {
 	shared_session_new_cbk = func;
 }
 
-/* Init shared memory context if not allocated and set SSL context callbacks
- * size is the max number of stored session 
- * Returns: -1 on alloc failure, size if performs context alloc, and 0 if just perform
- * callbacks registration */
-int shared_context_init(SSL_CTX *ctx, int size)
-{
-	int ret = 0;
-
-	if (!shctx) {
-		int i;
-
+/* Allocate shared memory context. 
+ * size is maximum cached sessions.
+ *      if set less or equal to 0, SHCTX_DEFAULT_SIZE is used.
+ * Returns: -1 on alloc failure, size if it performs context alloc,
+ * and 0 if cache is already allocated */
+int shared_context_init(int size) {
+	int i;
 #ifndef USE_SYSCALL_FUTEX
-		pthread_mutexattr_t attr;
+	pthread_mutexattr_t attr;
 #endif /* USE_SYSCALL_FUTEX */
-		struct shared_session *prev,*cur;
+	struct shared_session *prev,*cur;
 
-		shctx = (struct shared_context *)mmap(NULL, sizeof(struct shared_context)+(size*sizeof(struct shared_session)),
-								PROT_READ | PROT_WRITE, MAP_SHARED | MAP_ANONYMOUS, -1, 0);
-		if (!shctx || shctx == MAP_FAILED)
-			return -1;
+	if (shctx)
+		return 0;
+
+	if (size<=0)
+		size = SHCTX_DEFAULT_SIZE;
+
+	shctx = (struct shared_context *)mmap(NULL, sizeof(struct shared_context)+(size*sizeof(struct shared_session)),
+							PROT_READ | PROT_WRITE, MAP_SHARED | MAP_ANONYMOUS, -1, 0);
+	if (!shctx || shctx == MAP_FAILED) {
+		shctx = NULL;
+		return -1;
+	}
 
 #ifdef USE_SYSCALL_FUTEX
-		shctx->waiters = 0;
+	shctx->waiters = 0;
 #else
-		pthread_mutexattr_init(&attr);
-		pthread_mutexattr_setpshared(&attr, PTHREAD_PROCESS_SHARED);
-		pthread_mutex_init(&shctx->mutex, &attr);
+	pthread_mutexattr_init(&attr);
+	pthread_mutexattr_setpshared(&attr, PTHREAD_PROCESS_SHARED);
+	pthread_mutex_init(&shctx->mutex, &attr);
 #endif
-		memset(&shctx->active.key, 0, sizeof(struct ebmb_node));
-		memset(&shctx->free.key, 0, sizeof(struct ebmb_node));
+	memset(&shctx->active.key, 0, sizeof(struct ebmb_node));
+	memset(&shctx->free.key, 0, sizeof(struct ebmb_node));
 
-		/* No duplicate authorized in tree: */
-		shctx->active.key.node.branches.b[1] = (void *)1;
+	/* No duplicate authorized in tree: */
+	//shctx->active.key.node.branches.b[1] = (void *)1;
+	shctx->active.key.node.branches = EB_ROOT_UNIQUE;
 
-		cur = &shctx->active; 
-		cur->n = cur->p = cur;
+	cur = &shctx->active; 
+	cur->n = cur->p = cur;
 		
-		cur = &shctx->free;
-		for ( i = 0 ; i < size ; i++) {
-			prev = cur;
-			cur = (struct shared_session *)((char *)prev + sizeof(struct shared_session));
-			prev->n = cur;
-			cur->p = prev;
-		}
-		cur->n = &shctx->free;
-		shctx->free.p = cur;
-
-		ret = size;
+	cur = &shctx->free;
+	for ( i = 0 ; i < size ; i++) {
+		prev = cur;
+		cur = (struct shared_session *)((char *)prev + sizeof(struct shared_session));
+		prev->n = cur;
+		cur->p = prev;
 	}
+	cur->n = &shctx->free;
+	shctx->free.p = cur;
+
+	return size;
+}
+
 
-	/* set SSL internal cache size to external cache / 8  + 123 */
-	SSL_CTX_sess_set_cache_size(ctx, size >> 3 | 0x3ff);
+/* Set session cache mode to server and disable openssl internal cache. 
+ * Set shared cache callbacks on an ssl context.
+ * Shared context MUST be firstly initialized */
+void shared_context_set_cache(SSL_CTX *ctx) {
+
+	SSL_CTX_set_session_cache_mode(ctx, SSL_SESS_CACHE_SERVER
+						|SSL_SESS_CACHE_NO_INTERNAL
+						|SSL_SESS_CACHE_NO_AUTO_CLEAR);
+	if (!shctx)
+		return;
 
 	/* Set callbacks */
 	SSL_CTX_sess_set_new_cb(ctx, shctx_new_cb);
 	SSL_CTX_sess_set_get_cb(ctx, shctx_get_cb);
 	SSL_CTX_sess_set_remove_cb(ctx, shctx_remove_cb);
 
-	return ret;
 }
 
+
+
+
diff --git a/shctx.h b/shctx.h
index 42a600c..37cdf7b 100644
--- a/shctx.h
+++ b/shctx.h
@@ -21,11 +21,16 @@
 #define SHSESS_MAX_DATA_LEN 512
 #endif
 
+#ifndef SHCTX_DEFAULT_SIZE
+#define SHCTX_DEFAULT_SIZE 20000
+#endif
+
 #define SHSESS_MAX_ENCODED_LEN SSL_MAX_SSL_SESSION_ID_LENGTH \
 				+ SHSESS_MAX_DATA_LEN \
 				+ SHSESS_MAX_FOOTER_LEN
 
 
+
 /* Callback called on a new session event:
  * session contains the sessionid zeros padded to SSL_MAX_SSL_SESSION_ID_LENGTH
  *                                               followed by ASN1 session encoding.
@@ -44,10 +49,17 @@ void shsess_set_new_cbk(void (*func)(unsigned char *session, unsigned int len, l
  * if cdate not 0, on get events session creation date will be reset to cdate */
 void shctx_sess_add(const unsigned char *session, unsigned int session_len, long cdate);
 
-/* Init shared memory context if not allocated and set SSL context callbacks
- * size is the max number of stored session 
- * Returns: -1 on alloc failure, size if performs context alloc, and 0 if just
- * perform callbacks registration */
-int shared_context_init(SSL_CTX *ctx, int size);
+/* Allocate shared memory context. 
+ * size is maximum cached sessions.
+ *      if set less or equal to 0, SHCTX_DEFAULT_SIZE is used.
+ * Returns: -1 on alloc failure, size if it performs context alloc,
+ * and 0 if cache is already allocated */
+int shared_context_init(int size);
+
+/* Set shared cache callbacks on an ssl context.
+ * Set session cache mode to server and disable openssl internal cache. 
+ * Shared context MUST be firstly initialized */
+void shared_context_set_cache(SSL_CTX *ctx);
 
 #endif /* SHCTX_H */
+
diff --git a/stud.c b/stud.c
index 482fcc0..a126b51 100644
--- a/stud.c
+++ b/stud.c
@@ -615,10 +615,12 @@ SSL_CTX * init_openssl() {
     }
 #ifdef USE_SHARED_CACHE
     else if (CONFIG->SHARED_CACHE) {
-        if (shared_context_init(ctx, CONFIG->SHARED_CACHE) < 0) {
+        if (shared_context_init(CONFIG->SHARED_CACHE) < 0) {
             ERR("Unable to alloc memory for shared cache.\n");
             exit(1);
         }
+	shared_context_set_cache(ctx);
+
 	if (CONFIG->SHCUPD_PORT) {
             if (compute_secret(rsa, shared_secret) < 0) {
                 ERR("Unable to compute shared secret.\n");