vader: remove lock based fifos

This commit was SVN r26150.

ompi/mca/btl/vader/btl_vader_fbox.h

@@ -35,7 +35,6 @@ static inline unsigned char *mca_btl_vader_reserve_fbox (int peer_smp_rank, size
     unsigned char *fbox = MCA_BTL_VADER_FBOX_OUT_PTR(peer_smp_rank, next_fbox);  
 
     /* todo -- need thread locks/atomics here for the multi-threaded case */
-
     if (OPAL_UNLIKELY(size > MAX_MSG || fbox[0] != MCA_BTL_VADER_FBOX_FREE)) {
         /* fall back on fifo */
         return NULL;

ompi/mca/btl/vader/btl_vader_fifo.h

@@ -46,15 +46,12 @@
  * We introduce some padding at the end of the structure but it is probably unnecessary.
  */
 
-#if defined(OPAL_HAVE_ATOMIC_SWAP_64)
-
 /* lock free fifo */
-struct vader_fifo_t {
+typedef struct vader_fifo_t {
     volatile intptr_t fifo_head;
     volatile intptr_t fifo_tail;
     char pad[VADER_CACHE_LINE_PAD - 2 * sizeof (intptr_t)];
-};
+} vader_fifo_t;
-typedef struct vader_fifo_t vader_fifo_t;
 
 static inline int vader_fifo_init (vader_fifo_t *fifo)
 {
@@ -70,8 +67,8 @@ static inline void vader_fifo_write (mca_btl_vader_hdr_t *hdr, int rank)
 
     hdr->next = VADER_FIFO_FREE;
 
+    opal_atomic_wmb ();
     prev = opal_atomic_swap_ptr (&fifo->fifo_tail, value);
-
     opal_atomic_rmb ();
 
     if (OPAL_LIKELY(VADER_FIFO_FREE != prev)) {
@@ -100,6 +97,8 @@ static inline mca_btl_vader_hdr_t *vader_fifo_read (vader_fifo_t *fifo)
     hdr = (mca_btl_vader_hdr_t *) RELATIVE2VIRTUAL(value);
 
     if (OPAL_UNLIKELY(VADER_FIFO_FREE == hdr->next)) {
+        opal_atomic_rmb();
+
         if (!opal_atomic_cmpset_ptr (&fifo->fifo_tail, (void *)value,
                                      (void *)VADER_FIFO_FREE)) {
             while (VADER_FIFO_FREE == hdr->next) {
@@ -117,94 +116,4 @@ static inline mca_btl_vader_hdr_t *vader_fifo_read (vader_fifo_t *fifo)
     return hdr; 
 }
 
-#else /* defined(OPAL_HAVE_ATOMIC_SWAP_64) */
-
-struct vader_fifo_t {
-    volatile void *fifo_head;
-    opal_atomic_lock_t head_lock;
-    volatile void *fifo_tail;
-    opal_atomic_lock_t tail_lock;
-};
-typedef struct vader_fifo_t vader_fifo_t;
-
-static inline int vader_fifo_init (vader_fifo_t *fifo)
-{
-    fifo->fifo_head = fifo->fifo_tail = VADER_FIFO_FREE;
-    opal_atomic_init (&(fifo->head_lock), OPAL_ATOMIC_UNLOCKED);
-    opal_atomic_init (&(fifo->tail_lock), OPAL_ATOMIC_UNLOCKED);
-    opal_atomic_unlock(&(fifo->head_lock));  /* should be unnecessary */
-    opal_atomic_unlock(&(fifo->tail_lock));  /* should be unnecessary */
-
-    return OMPI_SUCCESS;
-}
-
-static inline int vader_fifo_write (void *value, vader_fifo_t *fifo)
-{
-    mca_btl_vader_hdr_t *hdr;
-    void *prev;
-    int rc;
-
-    hdr = (mca_btl_vader_hdr_t *) RELATIVE2VIRTUAL(value);
-    hdr->next = VADER_FIFO_FREE;
-
-    opal_atomic_rmb();
-
-    opal_atomic_lock(&(fifo->tail_lock));
-    prev = (void *) fifo->fifo_tail;
-    fifo->fifo_tail = value;
-
-    if (OPAL_LIKELY(VADER_FIFO_FREE != prev)) {
-        hdr = (mca_btl_vader_hdr_t *) RELATIVE2VIRTUAL(prev);
-        hdr->next = value;
-    } else {
-         fifo->fifo_head = value;
-    }
-
-    opal_atomic_unlock(&(fifo->tail_lock));
-
-    return OMPI_SUCCESS;
-}
-
-
-static inline void *vader_fifo_read (vader_fifo_t *fifo)
-{
-    mca_btl_vader_hdr_t *hdr;
-    void *value;
-    int rc;
-
-    /* aquire thread lock */
-    if (opal_using_threads ()) {
-        opal_atomic_lock (&fifo->head_lock);
-    }
-
-    opal_atomic_rmb();
-    if (VADER_FIFO_FREE == fifo->fifo_head) {
-        return VADER_FIFO_FREE;
-    }
-
-    value = (void *) fifo->fifo_head;
-    hdr = (mca_btl_vader_hdr_t *) RELATIVE2VIRTUAL(value);
-    fifo->fifo_head = hdr->next;
-
-    if (OPAL_UNLIKELY(VADER_FIFO_FREE == fifo->fifo_head)) {
-        opal_atomic_rmb();
-        opal_atomic_lock(&(fifo->tail_lock));
-
-        if (OPAL_LIKELY(fifo->fifo_tail == value)) {
-            fifo->fifo_tail = VADER_FIFO_FREE;
-        } else {
-            fifo->fifo_head = hdr->next;
-        }
-        opal_atomic_unlock(&(fifo->tail_lock));
-    }
-
-    /* release thread lock */
-    if (opal_using_threads ()) {
-        opal_atomic_unlock (&fifo->head_lock);
-    }
-    
-    return value;
-}
-#endif /* else !defined(OPAL_HAVE_ATOMIC_SWAP_64) */
-
 #endif /* MCA_BTL_VADER_FIFO_H */

ompi/mca/btl/vader/btl_vader_frag.h

@@ -31,7 +31,7 @@
 #define MCA_BTL_VADER_FLAG_FBOX        2
 
 struct mca_btl_vader_hdr_t {
-    volatile uintptr_t next;    /* next item in fifo. many peers may touch this */
+    volatile intptr_t next; /* next item in fifo. many peers may touch this */
     volatile bool complete; /* fragment completion (usually 1 byte) */
     mca_btl_base_tag_t tag; /* tag associated with this fragment (used to lookup callback) */
     char pad[2];