diff --git a/ompi/mca/coll/ucc/coll_ucc_allgather.c b/ompi/mca/coll/ucc/coll_ucc_allgather.c
index b620d9529a2..21f63330bfa 100644
--- a/ompi/mca/coll/ucc/coll_ucc_allgather.c
+++ b/ompi/mca/coll/ucc/coll_ucc_allgather.c
@@ -34,6 +34,7 @@ static inline ucc_status_t mca_coll_ucc_allgather_init(const void *sbuf, int sco
 
     ucc_coll_args_t coll = {
         .mask      = 0,
+        .flags     = 0,
         .coll_type = UCC_COLL_TYPE_ALLGATHER,
         .src.info = {
             .buffer   = (void*)sbuf,
diff --git a/ompi/mca/coll/ucc/coll_ucc_allgatherv.c b/ompi/mca/coll/ucc/coll_ucc_allgatherv.c
index 6cf33a5dd80..a6bb37d235b 100644
--- a/ompi/mca/coll/ucc/coll_ucc_allgatherv.c
+++ b/ompi/mca/coll/ucc/coll_ucc_allgatherv.c
@@ -31,6 +31,7 @@ static inline ucc_status_t mca_coll_ucc_allgatherv_init(const void *sbuf, int sc
 
     ucc_coll_args_t coll = {
         .mask      = 0,
+        .flags     = 0,
         .coll_type = UCC_COLL_TYPE_ALLGATHERV,
         .src.info = {
             .buffer        = (void*)sbuf,
diff --git a/ompi/mca/coll/ucc/coll_ucc_allreduce.c b/ompi/mca/coll/ucc/coll_ucc_allreduce.c
index a46a59db337..0f10a771c62 100644
--- a/ompi/mca/coll/ucc/coll_ucc_allreduce.c
+++ b/ompi/mca/coll/ucc/coll_ucc_allreduce.c
@@ -32,6 +32,7 @@ static inline ucc_status_t mca_coll_ucc_allreduce_init(const void *sbuf, void *r
     }
     ucc_coll_args_t coll = {
         .mask      = 0,
+        .flags     = 0,
         .coll_type = UCC_COLL_TYPE_ALLREDUCE,
         .src.info = {
             .buffer   = (void*)sbuf,
diff --git a/ompi/mca/coll/ucc/coll_ucc_alltoall.c b/ompi/mca/coll/ucc/coll_ucc_alltoall.c
index d6871f23b69..cc321a915a5 100644
--- a/ompi/mca/coll/ucc/coll_ucc_alltoall.c
+++ b/ompi/mca/coll/ucc/coll_ucc_alltoall.c
@@ -34,6 +34,7 @@ static inline ucc_status_t mca_coll_ucc_alltoall_init(const void *sbuf, int scou
 
     ucc_coll_args_t coll = {
         .mask      = 0,
+        .flags     = 0,
         .coll_type = UCC_COLL_TYPE_ALLTOALL,
         .src.info = {
             .buffer   = (void*)sbuf,
diff --git a/ompi/mca/coll/ucc/coll_ucc_alltoallv.c b/ompi/mca/coll/ucc/coll_ucc_alltoallv.c
index 75b0dd6b6b7..2dc1a121bf0 100644
--- a/ompi/mca/coll/ucc/coll_ucc_alltoallv.c
+++ b/ompi/mca/coll/ucc/coll_ucc_alltoallv.c
@@ -31,6 +31,7 @@ static inline ucc_status_t mca_coll_ucc_alltoallv_init(const void *sbuf, const i
 
     ucc_coll_args_t coll = {
         .mask      = 0,
+        .flags     = 0,
         .coll_type = UCC_COLL_TYPE_ALLTOALLV,
         .src.info_v = {
             .buffer        = (void*)sbuf,
diff --git a/ompi/mca/coll/ucc/coll_ucc_barrier.c b/ompi/mca/coll/ucc/coll_ucc_barrier.c
index fdbc11b49aa..010ca177fdf 100644
--- a/ompi/mca/coll/ucc/coll_ucc_barrier.c
+++ b/ompi/mca/coll/ucc/coll_ucc_barrier.c
@@ -14,6 +14,7 @@ static inline ucc_status_t mca_coll_ucc_barrier_init(mca_coll_ucc_module_t *ucc_
 {
     ucc_coll_args_t coll = {
         .mask      = 0,
+        .flags     = 0,
         .coll_type = UCC_COLL_TYPE_BARRIER
     };
     COLL_UCC_REQ_INIT(coll_req, req, coll, ucc_module);
diff --git a/ompi/mca/coll/ucc/coll_ucc_bcast.c b/ompi/mca/coll/ucc/coll_ucc_bcast.c
index 661f336e64d..8fa7ee58ba7 100644
--- a/ompi/mca/coll/ucc/coll_ucc_bcast.c
+++ b/ompi/mca/coll/ucc/coll_ucc_bcast.c
@@ -21,6 +21,7 @@ static inline ucc_status_t mca_coll_ucc_bcast_init(void *buf, int count, struct
 
     ucc_coll_args_t coll = {
         .mask      = 0,
+        .flags     = 0,
         .coll_type = UCC_COLL_TYPE_BCAST,
         .root = root,
         .src.info = {
diff --git a/ompi/mca/coll/ucc/coll_ucc_common.h b/ompi/mca/coll/ucc/coll_ucc_common.h
index 5ae034d7ff5..9d9163aa46d 100644
--- a/ompi/mca/coll/ucc/coll_ucc_common.h
+++ b/ompi/mca/coll/ucc/coll_ucc_common.h
@@ -47,6 +47,9 @@
             _coll.mask   |= UCC_COLL_ARGS_FIELD_CB;                     \
             _coll.cb.cb   = mca_coll_ucc_completion;                    \
             _coll.cb.data = (void*)_coll_req;                           \
+        } else {                                                        \
+            _coll.mask  |= UCC_COLL_ARGS_FIELD_FLAGS;                   \
+            _coll.flags |= UCC_COLL_ARGS_HINT_OPTIMIZE_LATENCY;         \
         }                                                               \
         COLL_UCC_CHECK(ucc_collective_init(&_coll, _req,                \
                                            _module->ucc_team));         \
diff --git a/ompi/mca/coll/ucc/coll_ucc_gather.c b/ompi/mca/coll/ucc/coll_ucc_gather.c
index 42213e9d97d..b7990ccea64 100644
--- a/ompi/mca/coll/ucc/coll_ucc_gather.c
+++ b/ompi/mca/coll/ucc/coll_ucc_gather.c
@@ -47,6 +47,7 @@ ucc_status_t mca_coll_ucc_gather_init(const void *sbuf, int scount, struct ompi_
 
     ucc_coll_args_t coll = {
         .mask      = 0,
+        .flags     = 0,
         .coll_type = UCC_COLL_TYPE_GATHER,
         .root      = root,
         .src.info = {
diff --git a/ompi/mca/coll/ucc/coll_ucc_gatherv.c b/ompi/mca/coll/ucc/coll_ucc_gatherv.c
index 81474d0c38a..74db288ee17 100644
--- a/ompi/mca/coll/ucc/coll_ucc_gatherv.c
+++ b/ompi/mca/coll/ucc/coll_ucc_gatherv.c
@@ -19,7 +19,6 @@ static inline ucc_status_t mca_coll_ucc_gatherv_init(const void *sbuf, int scoun
 {
     ucc_datatype_t ucc_sdt, ucc_rdt;
     int comm_rank = ompi_comm_rank(ucc_module->comm);
-    int comm_size = ompi_comm_size(ucc_module->comm);
 
     ucc_sdt = ompi_dtype_to_ucc_dtype(sdtype);
     if (comm_rank == root) {
@@ -41,6 +40,7 @@ static inline ucc_status_t mca_coll_ucc_gatherv_init(const void *sbuf, int scoun
 
     ucc_coll_args_t coll = {
         .mask      = 0,
+        .flags     = 0,
         .coll_type = UCC_COLL_TYPE_GATHERV,
         .root      = root,
         .src.info = {
diff --git a/ompi/mca/coll/ucc/coll_ucc_module.c b/ompi/mca/coll/ucc/coll_ucc_module.c
index 32861d315de..14d3d732b9a 100644
--- a/ompi/mca/coll/ucc/coll_ucc_module.c
+++ b/ompi/mca/coll/ucc/coll_ucc_module.c
@@ -94,7 +94,7 @@ static void mca_coll_ucc_module_construct(mca_coll_ucc_module_t *ucc_module)
     mca_coll_ucc_module_clear(ucc_module);
 }
 
-int mca_coll_ucc_progress(void)
+static int mca_coll_ucc_progress(void)
 {
     ucc_context_progress(mca_coll_ucc_component.ucc_context);
     return OPAL_SUCCESS;
diff --git a/ompi/mca/coll/ucc/coll_ucc_reduce.c b/ompi/mca/coll/ucc/coll_ucc_reduce.c
index c936caad312..28edc413c9d 100644
--- a/ompi/mca/coll/ucc/coll_ucc_reduce.c
+++ b/ompi/mca/coll/ucc/coll_ucc_reduce.c
@@ -31,7 +31,8 @@ static inline ucc_status_t mca_coll_ucc_reduce_init(const void *sbuf, void *rbuf
         goto fallback;
     }
     ucc_coll_args_t coll = {
-        .mask = 0,
+        .mask      = 0,
+        .flags     = 0,
         .coll_type = UCC_COLL_TYPE_REDUCE,
         .root = root,
         .src.info = {
diff --git a/ompi/mca/coll/ucc/coll_ucc_reduce_scatter.c b/ompi/mca/coll/ucc/coll_ucc_reduce_scatter.c
index 5cc6fa6fc61..15771e48f1b 100644
--- a/ompi/mca/coll/ucc/coll_ucc_reduce_scatter.c
+++ b/ompi/mca/coll/ucc/coll_ucc_reduce_scatter.c
@@ -48,6 +48,7 @@ ucc_status_t mca_coll_ucc_reduce_scatter_init(const void *sbuf, void *rbuf, cons
 
     ucc_coll_args_t coll = {
         .mask      = 0,
+        .flags     = 0,
         .coll_type = UCC_COLL_TYPE_REDUCE_SCATTERV,
         .src.info = {
             .buffer   = (void*)sbuf,
diff --git a/ompi/mca/coll/ucc/coll_ucc_reduce_scatter_block.c b/ompi/mca/coll/ucc/coll_ucc_reduce_scatter_block.c
index 88d6f4c6628..cce77365227 100644
--- a/ompi/mca/coll/ucc/coll_ucc_reduce_scatter_block.c
+++ b/ompi/mca/coll/ucc/coll_ucc_reduce_scatter_block.c
@@ -42,6 +42,7 @@ ucc_status_t mca_coll_ucc_reduce_scatter_block_init(const void *sbuf, void *rbuf
     }
     ucc_coll_args_t coll = {
         .mask      = 0,
+        .flags     = 0,
         .coll_type = UCC_COLL_TYPE_REDUCE_SCATTER,
         .src.info = {
             .buffer   = (void*)sbuf,
diff --git a/ompi/mca/coll/ucc/coll_ucc_scatter.c b/ompi/mca/coll/ucc/coll_ucc_scatter.c
index 130718619b4..cc20104705f 100644
--- a/ompi/mca/coll/ucc/coll_ucc_scatter.c
+++ b/ompi/mca/coll/ucc/coll_ucc_scatter.c
@@ -42,6 +42,7 @@ ucc_status_t mca_coll_ucc_scatter_init(const void *sbuf, int scount,
 
     ucc_coll_args_t coll = {
         .mask      = 0,
+        .flags     = 0,
         .coll_type = UCC_COLL_TYPE_SCATTER,
         .root      = root,
         .src.info  = {
diff --git a/ompi/mca/coll/ucc/coll_ucc_scatterv.c b/ompi/mca/coll/ucc/coll_ucc_scatterv.c
index b731850fabe..b478df7fb11 100644
--- a/ompi/mca/coll/ucc/coll_ucc_scatterv.c
+++ b/ompi/mca/coll/ucc/coll_ucc_scatterv.c
@@ -43,6 +43,7 @@ ucc_status_t mca_coll_ucc_scatterv_init(const void *sbuf, const int *scounts,
 
     ucc_coll_args_t coll = {
         .mask      = 0,
+        .flags     = 0,
         .coll_type = UCC_COLL_TYPE_SCATTERV,
         .root      = root,
         .src.info_v = {