erts: Remove a copy of distribution data payload

Before this change the inet driver was in list mode and
thus the data from it had to be copied when received by
the dist entry. This change puts the tcp port in binary mode
and makes the any refc binary created by it be used all the way
to the process where it is decoded.

Thus eliminating one copy of the entire message payload.

1 files changed, 28 insertions, 6 deletions

diff --git a/erts/emulator/beam/external.c b/erts/emulator/beam/external.c
index 9a66e491f3..4b8040b356 100644
--- a/erts/emulator/beam/external.c
+++ b/erts/emulator/beam/external.c
@@ -640,14 +640,15 @@ erts_make_dist_ext_copy(ErtsDistExternal *edep, Uint xsize)
 {
     size_t align_sz;
     size_t dist_ext_sz;
-    size_t ext_sz;
+    size_t ext_sz = 0;
     byte *ep;
     ErtsDistExternal *new_edep;
 
     dist_ext_sz = ERTS_DIST_EXT_SIZE(edep);
     ASSERT(edep->ext_endp && edep->extp);
     ASSERT(edep->ext_endp >= edep->extp);
-    ext_sz = edep->ext_endp - edep->extp;
+    if (edep->binp == NULL)
+        ext_sz = edep->ext_endp - edep->extp;
 
     align_sz = ERTS_EXTRA_DATA_ALIGN_SZ(dist_ext_sz + ext_sz);
 
@@ -656,20 +657,36 @@ erts_make_dist_ext_copy(ErtsDistExternal *edep, Uint xsize)
 
     ep = (byte *) new_edep;
     sys_memcpy((void *) ep, (void *) edep, dist_ext_sz);
-    ep += dist_ext_sz;
     if (new_edep->dep)
         erts_ref_dist_entry(new_edep->dep);
-    new_edep->extp = ep;
-    new_edep->ext_endp = ep + ext_sz;
     new_edep->heap_size = -1;
-    sys_memcpy((void *) ep, (void *) edep->extp, ext_sz);
+
+    if (ext_sz) {
+        ep += dist_ext_sz;
+        new_edep->extp = ep;
+        new_edep->ext_endp = ep + ext_sz;
+        sys_memcpy((void *) ep, (void *) edep->extp, ext_sz);
+    } else {
+        erts_refc_inc(&new_edep->binp->intern.refc, 2);
+    }
     return new_edep;
 }
 
+void
+erts_free_dist_ext_copy(ErtsDistExternal *edep)
+{
+    if (edep->dep)
+	erts_deref_dist_entry(edep->dep);
+    if (edep->binp)
+        erts_bin_release(edep->binp);
+    erts_free(ERTS_ALC_T_EXT_TERM_DATA, edep);
+}
+
 int
 erts_prepare_dist_ext(ErtsDistExternal *edep,
 		      byte *ext,
 		      Uint size,
+                      Binary *binp,
 		      DistEntry *dep,
                       Uint32 conn_id,
 		      ErtsAtomCache *cache)
@@ -685,6 +702,7 @@ erts_prepare_dist_ext(ErtsDistExternal *edep,
 
     ASSERT(dep->flags & DFLAG_UTF8_ATOMS);
 
+
     if ((dep->state != ERTS_DE_STATE_CONNECTED &&
          dep->state != ERTS_DE_STATE_PENDING)
         || dep->connection_id != conn_id) {
@@ -697,7 +715,11 @@ erts_prepare_dist_ext(ErtsDistExternal *edep,
         ext++;
         size--;
     }
+
+    edep->heap_size = -1;
     edep->ext_endp = ext + size;
+    edep->binp = binp;
+
     ep = ext;
 
     if (size < 2)