diff --git a/c_src/decoder.c b/c_src/decoder.c
index c1af71e..db140dc 100644
--- a/c_src/decoder.c
+++ b/c_src/decoder.c
@@ -91,7 +91,7 @@ dec_new(ErlNifEnv* env)
     d->p = NULL;
     d->u = NULL;
     d->len = -1;
-    d->i = -1;
+    d->i = 0;
 
     d->st_data = (char*) enif_alloc(STACK_SIZE_INC);
     d->st_size = STACK_SIZE_INC;
@@ -116,16 +116,6 @@ dec_init(Decoder* d, ErlNifEnv* env, ERL_NIF_TERM arg, ErlNifBinary* bin)
     d->p = (char*) bin->data;
     d->u = bin->data;
     d->len = bin->size;
-
-    // I'd like to be more forceful on this check so that when
-    // we run a second iteration of the decoder we are sure
-    // that we're using the same binary. Unfortunately, I don't
-    // think there's a value to base this assertion on.
-    if(d->i < 0) {
-        d->i = 0;
-    } else {
-        assert(d->i <= d->len && "mismatched binary lengths");
-    }
 }
 
 void
@@ -715,38 +705,56 @@ decode_iter(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
     ERL_NIF_TERM val = argv[2];
     ERL_NIF_TERM trailer;
     ERL_NIF_TERM ret;
-    size_t bytes_read = 0;
+    ERL_NIF_TERM tmp_argv[5];
 
-    if(argc != 5) {
-        return enif_make_badarg(env);
-    } else if(!enif_inspect_binary(env, argv[0], &bin)) {
+    size_t start;
+    size_t bytes_processed = 0;
+
+    if(!enif_inspect_binary(env, argv[0], &bin)) {
         return enif_make_badarg(env);
     } else if(!enif_get_resource(env, argv[1], st->res_dec, (void**) &d)) {
         return enif_make_badarg(env);
-    } else if(!enif_is_list(env, argv[3])) {
-        return enif_make_badarg(env);
-    } else if(!enif_is_list(env, argv[4])) {
-        return enif_make_badarg(env);
     }
 
     dec_init(d, env, argv[0], &bin);
     objs = argv[3];
     curr = argv[4];
 
+    start = d->i;
+
     while(d->i < bin.size) {
-        if(should_yield(env, &bytes_read, d->bytes_per_red)) {
-            return enif_make_tuple5(
+        bytes_processed = d->i - start;
+
+        if(should_yield(bytes_processed, d->bytes_per_red)) {
+            assert(enif_is_list(env, objs));
+            assert(enif_is_list(env, curr));
+
+            tmp_argv[0] = argv[0];
+            tmp_argv[1] = argv[1];
+            tmp_argv[2] = val;
+            tmp_argv[3] = objs;
+            tmp_argv[4] = curr;
+
+            bump_used_reds(env, bytes_processed, d->bytes_per_red);
+
+#if SCHEDULE_NIF_PRESENT
+            return enif_schedule_nif(
+                    env,
+                    "nif_decode_iter",
+                    0,
+                    decode_iter,
+                    5,
+                    tmp_argv
+                );
+#else
+            return enif_make_tuple2(
                     env,
                     st->atom_iter,
-                    argv[1],
-                    val,
-                    objs,
-                    curr
+                    enif_make_tuple(env, 5, tmp_argv)
                 );
+#endif
         }
 
-        bytes_read += 1;
-
         switch(dec_curr(d)) {
             case st_value:
                 switch(d->p[d->i]) {
@@ -1040,5 +1048,7 @@ decode_done:
     }
 
 done:
+    bump_used_reds(env, bytes_processed, d->bytes_per_red);
+
     return ret;
 }
diff --git a/c_src/encoder.c b/c_src/encoder.c
index fdae2d1..08b74a1 100644
--- a/c_src/encoder.c
+++ b/c_src/encoder.c
@@ -731,20 +731,15 @@ encode_iter(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
 
     ERL_NIF_TERM curr;
     ERL_NIF_TERM item;
-    ERL_NIF_TERM saved_stack;
     const ERL_NIF_TERM* tuple;
     int arity;
     ErlNifSInt64 lval;
     double dval;
 
     size_t start;
-    size_t bytes_written = 0;
+    size_t bytes_processed = 0;
 
-    if(argc != 3) {
-        return enif_make_badarg(env);
-    } else if(!enif_get_resource(env, argv[0], st->res_enc, (void**) &e)) {
-        return enif_make_badarg(env);
-    } else if(!enif_is_list(env, argv[2])) {
+    if(!enif_get_resource(env, argv[0], st->res_enc, (void**) &e)) {
         return enif_make_badarg(env);
     }
 
@@ -761,19 +756,36 @@ encode_iter(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
     start = e->iosize + e->i;
 
     while(!termstack_is_empty(&stack)) {
-        bytes_written += (e->iosize + e->i) - start;
+        bytes_processed = (e->iosize + e->i) - start;
+
+        if(should_yield(bytes_processed, e->bytes_per_red)) {
+            ERL_NIF_TERM tmp_argv[3];
+
+            assert(enif_is_list(env, e->iolist));
+
+            tmp_argv[0] = argv[0];
+            tmp_argv[1] = termstack_save(env, &stack);
+            tmp_argv[2] = e->iolist;
 
-        if(should_yield(env, &bytes_written, e->bytes_per_red)) {
-            saved_stack = termstack_save(env, &stack);
             termstack_destroy(&stack);
+            bump_used_reds(env, bytes_processed, e->bytes_per_red);
 
-            return enif_make_tuple4(
+#if SCHEDULE_NIF_PRESENT
+            return enif_schedule_nif(
+                    env,
+                    "nif_encode_iter",
+                    0,
+                    encode_iter,
+                    3,
+                    tmp_argv
+                );
+#else
+            return enif_make_tuple2(
                     env,
                     st->atom_iter,
-                    argv[0],
-                    saved_stack,
-                    e->iolist
+                    enif_make_tuple(env, 3, tmp_argv)
                 );
+#endif
         }
 
         curr = termstack_pop(&stack);
@@ -956,6 +968,7 @@ encode_iter(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
     }
 
 done:
+    bump_used_reds(env, bytes_processed, e->bytes_per_red);
     termstack_destroy(&stack);
 
     return ret;
diff --git a/c_src/jiffy.h b/c_src/jiffy.h
index ef03a06..7145b05 100644
--- a/c_src/jiffy.h
+++ b/c_src/jiffy.h
@@ -13,6 +13,12 @@
     ((ERL_NIF_MAJOR_VERSION == 2 && ERL_NIF_MINOR_VERSION >= 6) \
     || (ERL_NIF_MAJOR_VERSION > 2))
 
+#define CONSUME_TIMESLICE_PRESENT \
+        ((ERL_NIF_MAJOR_VERSION >= 2 && ERL_NIF_MINOR_VERSION >= 4))
+
+#define SCHEDULE_NIF_PRESENT \
+        ((ERL_NIF_MAJOR_VERSION >= 2 && ERL_NIF_MINOR_VERSION >= 7))
+
 typedef struct {
     ERL_NIF_TERM    atom_ok;
     ERL_NIF_TERM    atom_error;
@@ -53,7 +59,8 @@ ERL_NIF_TERM make_obj_error(jiffy_st* st, ErlNifEnv* env, const char* error,
 int get_bytes_per_iter(ErlNifEnv* env, ERL_NIF_TERM val, size_t* bpi);
 int get_bytes_per_red(ErlNifEnv* env, ERL_NIF_TERM val, size_t* bpr);
 int get_null_term(ErlNifEnv* env, ERL_NIF_TERM val, ERL_NIF_TERM *null_term);
-int should_yield(ErlNifEnv* env, size_t* used, size_t bytes_per_red);
+int should_yield(size_t used, size_t bytes_per_red);
+void bump_used_reds(ErlNifEnv* env, size_t used, size_t bytes_per_red);
 
 ERL_NIF_TERM decode_init(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
 ERL_NIF_TERM decode_iter(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]);
diff --git a/c_src/util.c b/c_src/util.c
index 7d8ac74..2890a63 100644
--- a/c_src/util.c
+++ b/c_src/util.c
@@ -122,20 +122,31 @@ get_null_term(ErlNifEnv* env, ERL_NIF_TERM val, ERL_NIF_TERM *null_term)
 }
 
 int
-should_yield(ErlNifEnv* env, size_t* used, size_t bytes_per_red)
+should_yield(size_t used, size_t bytes_per_red)
 {
-#if(ERL_NIF_MAJOR_VERSION >= 2 && ERL_NIF_MINOR_VERSION >= 4)
-
-    if(((*used) / bytes_per_red) >= 20) {
-        *used = 0;
-        return enif_consume_timeslice(env, 1);
-    }
+    return (used / bytes_per_red) >= DEFAULT_ERLANG_REDUCTION_COUNT;
+}
 
-    return 0;
+void
+bump_used_reds(ErlNifEnv* env, size_t used, size_t bytes_per_red)
+{
+#if CONSUME_TIMESLICE_PRESENT
+    size_t reds_used;
+    size_t pct_used;
 
-#else
+    reds_used = used / bytes_per_red;
+    pct_used = 100 * reds_used / DEFAULT_ERLANG_REDUCTION_COUNT;
 
-    return ((*used) / bytes_per_red) >= DEFAULT_ERLANG_REDUCTION_COUNT;
+    if(pct_used > 0) {
+        if(pct_used > 100) {
+            pct_used = 100;
+        }
 
+        enif_consume_timeslice(env, pct_used);
+    }
 #endif
+
+    (void) env;
+    (void) used;
+    (void) bytes_per_red;
 }
diff --git a/src/jiffy.erl b/src/jiffy.erl
index c82eba4..164fa5b 100644
--- a/src/jiffy.erl
+++ b/src/jiffy.erl
@@ -71,7 +71,7 @@ decode(Data, Opts) when is_binary(Data), is_list(Opts) ->
             error(Error);
         {partial, EJson} ->
             finish_decode(EJson);
-        {iter, Decoder, Val, Objs, Curr} ->
+        {iter, {_, Decoder, Val, Objs, Curr}} ->
             decode_loop(Data, Decoder, Val, Objs, Curr);
         EJson ->
             EJson
@@ -99,7 +99,7 @@ encode(Data, Options) ->
             error(Error);
         {partial, IOData} ->
             finish_encode(IOData, []);
-        {iter, Encoder, Stack, IOBuf} ->
+        {iter, {Encoder, Stack, IOBuf}} ->
             encode_loop(Data, Options, Encoder, Stack, IOBuf);
         IOData ->
             IOData
@@ -184,7 +184,7 @@ decode_loop(Data, Decoder, Val, Objs, Curr) ->
             error(Error);
         {partial, EJson} ->
             finish_decode(EJson);
-        {iter, NewDecoder, NewVal, NewObjs, NewCurr} ->
+        {iter, {_, NewDecoder, NewVal, NewObjs, NewCurr}} ->
             decode_loop(Data, NewDecoder, NewVal, NewObjs, NewCurr);
         EJson ->
             EJson
@@ -204,7 +204,7 @@ encode_loop(Data, Options, Encoder, Stack, IOBuf) ->
             error(Error);
         {partial, IOData} ->
             finish_encode(IOData, []);
-        {iter, NewEncoder, NewStack, NewIOBuf} ->
+        {iter, {NewEncoder, NewStack, NewIOBuf}} ->
             encode_loop(Data, Options, NewEncoder, NewStack, NewIOBuf);
         IOData ->
             IOData