diff --git a/src/components/tl/ucp/allgather/allgather.h b/src/components/tl/ucp/allgather/allgather.h
index 61733a4ab7..f6b7d54bfd 100644
--- a/src/components/tl/ucp/allgather/allgather.h
+++ b/src/components/tl/ucp/allgather/allgather.h
@@ -7,6 +7,8 @@
 #define ALLGATHER_H_
 #include "../tl_ucp.h"
 #include "../tl_ucp_coll.h"
+ #include "tl_ucp_sendrecv.h"
+
 
 enum {
     UCC_TL_UCP_ALLGATHER_ALG_KNOMIAL,
@@ -36,6 +38,7 @@ static inline int ucc_tl_ucp_allgather_alg_from_str(const char *str)
     return i;
 }
 
+
 ucc_status_t ucc_tl_ucp_allgather_init(ucc_tl_ucp_task_t *task);
 
 /* Ring */
diff --git a/src/components/tl/ucp/allgather/allgather_bruck.c b/src/components/tl/ucp/allgather/allgather_bruck.c
index 507136805f..959e687a9b 100644
--- a/src/components/tl/ucp/allgather/allgather_bruck.c
+++ b/src/components/tl/ucp/allgather/allgather_bruck.c
@@ -254,4 +254,4 @@ ucc_status_t ucc_tl_ucp_allgather_bruck_start(ucc_coll_task_t *coll_task)
     }
 
     return ucc_progress_queue_enqueue(UCC_TL_CORE_CTX(team)->pq, &task->super);
-}
+}
\ No newline at end of file
diff --git a/src/components/tl/ucp/allgather/allgather_knomial.c b/src/components/tl/ucp/allgather/allgather_knomial.c
index 1fbcf773cc..ecee9134f5 100644
--- a/src/components/tl/ucp/allgather/allgather_knomial.c
+++ b/src/components/tl/ucp/allgather/allgather_knomial.c
@@ -13,6 +13,9 @@
 #include "coll_patterns/sra_knomial.h"
 #include "utils/ucc_math.h"
 #include "utils/ucc_coll_utils.h"
+#include "allgather.h"
+
+
 
 #define SAVE_STATE(_phase)                                                     \
     do {                                                                       \
@@ -52,6 +55,7 @@
  * As such allgather must keep to this ranking to be aligned with scatter.
  */
 
+
 void ucc_tl_ucp_allgather_knomial_progress(ucc_coll_task_t *coll_task)
 {
     ucc_tl_ucp_task_t     *task      = ucc_derived_of(coll_task,
@@ -78,9 +82,17 @@ void ucc_tl_ucp_allgather_knomial_progress(ucc_coll_task_t *coll_task)
     ucc_status_t           status;
     size_t                 extra_count;
 
-    EXEC_TASK_TEST(UCC_KN_PHASE_INIT, "failed during ee task test",
-                   task->allgather_kn.etask);
+    int use_cuda = UCC_TL_UCP_TEAM_LIB(team)->cfg.allgather_use_cuda;
+
+    if (!use_cuda) {
+        if (UCC_INPROGRESS == ucc_tl_ucp_test(task)){
+            return;
+        }
+    }
+    
+    if (use_cuda) EXEC_TASK_TEST(UCC_KN_PHASE_INIT, "failed during ee task test", task->allgather_kn.etask);
     task->allgather_kn.etask = NULL;
+    
     UCC_KN_GOTO_PHASE(task->allgather_kn.phase);
     if (KN_NODE_EXTRA == node_type) {
         peer = ucc_knomial_pattern_get_proxy(p, rank);
@@ -197,6 +209,7 @@ void ucc_tl_ucp_allgather_knomial_progress(ucc_coll_task_t *coll_task)
 
 ucc_status_t ucc_tl_ucp_allgather_knomial_start(ucc_coll_task_t *coll_task)
 {
+    
     ucc_tl_ucp_task_t          *task  = ucc_derived_of(coll_task,
                                                        ucc_tl_ucp_task_t);
     ucc_coll_args_t            *args  = &TASK_ARGS(task);
@@ -214,6 +227,8 @@ ucc_status_t ucc_tl_ucp_allgather_knomial_start(ucc_coll_task_t *coll_task)
     ucc_ee_executor_t *exec;
     void              *rbuf;
 
+    int use_cuda = UCC_TL_UCP_TEAM_LIB(team)->cfg.allgather_use_cuda;
+
     UCC_TL_UCP_PROFILE_REQUEST_EVENT(coll_task, "ucp_allgather_kn_start", 0);
     ucc_tl_ucp_task_reset(task, UCC_INPROGRESS);
     task->allgather_kn.etask = NULL;
@@ -225,21 +240,29 @@ ucc_status_t ucc_tl_ucp_allgather_knomial_start(ucc_coll_task_t *coll_task)
                  ucc_dt_size(args->dst.info.datatype);
         rbuf   = args->dst.info.buffer;
         if (!UCC_IS_INPLACE(*args)) {
-            status = ucc_coll_task_get_executor(&task->super, &exec);
-            if (ucc_unlikely(status != UCC_OK)) {
-                task->super.status = status;
-                return status;
-            }
-            eargs.task_type = UCC_EE_EXECUTOR_TASK_COPY;
-            eargs.copy.dst  = PTR_OFFSET(args->dst.info.buffer, offset);
-            eargs.copy.src  = args->src.info.buffer;
-            eargs.copy.len  = args->src.info.count *
-                              ucc_dt_size(args->src.info.datatype);
-            status = ucc_ee_executor_task_post(exec, &eargs,
-                                               &task->allgather_kn.etask);
-            if (ucc_unlikely(status != UCC_OK)) {
-                task->super.status = status;
-                return status;
+            if (use_cuda) {
+                status = ucc_coll_task_get_executor(&task->super, &exec);
+                if (ucc_unlikely(status != UCC_OK)) {
+                    task->super.status = status;
+                    return status;
+                }
+                eargs.task_type = UCC_EE_EXECUTOR_TASK_COPY;
+                eargs.copy.dst  = PTR_OFFSET(args->dst.info.buffer, offset);
+                eargs.copy.src  = args->src.info.buffer;
+                eargs.copy.len  = args->src.info.count *
+                                ucc_dt_size(args->src.info.datatype);
+                status = ucc_ee_executor_task_post(exec, &eargs,
+                                                &task->allgather_kn.etask);
+                if (ucc_unlikely(status != UCC_OK)) {
+                    task->super.status = status;
+                    return status;
+                }
+            } else {
+                /*Loopback*/
+                UCPCHECK_GOTO(ucc_tl_ucp_send_nb(args->src.info.buffer, args->src.info.count * ucc_dt_size(args->src.info.datatype),
+                                args->src.info.mem_type, rank, team, task),task, out);
+                UCPCHECK_GOTO(ucc_tl_ucp_recv_nb(PTR_OFFSET(args->dst.info.buffer, offset), args->src.info.count * ucc_dt_size(args->src.info.datatype),
+                                args->dst.info.mem_type, rank, team, task),task, out);
             }
         }
     } else if (ct == UCC_COLL_TYPE_ALLGATHERV) {
@@ -284,6 +307,8 @@ ucc_status_t ucc_tl_ucp_allgather_knomial_start(ucc_coll_task_t *coll_task)
     task->allgather_kn.sbuf = PTR_OFFSET(rbuf, offset);
 
     return ucc_progress_queue_enqueue(UCC_TL_CORE_CTX(team)->pq, &task->super);
+out:
+    return task->super.status;
 }
 
 ucc_status_t ucc_tl_ucp_allgather_knomial_init_r(
@@ -293,8 +318,9 @@ ucc_status_t ucc_tl_ucp_allgather_knomial_init_r(
     ucc_tl_ucp_team_t *tl_team = ucc_derived_of(team, ucc_tl_ucp_team_t);
     ucc_tl_ucp_task_t *task;
     ucc_sbgp_t        *sbgp;
-
     task = ucc_tl_ucp_init_task(coll_args, team);
+    //ucc_coll_args_t   *args = &coll_args->args;
+
     if (tl_team->cfg.use_reordering &&
         coll_args->args.coll_type == UCC_COLL_TYPE_ALLREDUCE) {
         sbgp = ucc_topo_get_sbgp(tl_team->topo, UCC_SBGP_FULL_HOST_ORDERED);
@@ -306,6 +332,7 @@ ucc_status_t ucc_tl_ucp_allgather_knomial_init_r(
     task->super.post           = ucc_tl_ucp_allgather_knomial_start;
     task->super.progress       = ucc_tl_ucp_allgather_knomial_progress;
     *task_h                    = &task->super;
+
     return UCC_OK;
 }
 
@@ -316,7 +343,6 @@ ucc_status_t ucc_tl_ucp_allgather_knomial_init(ucc_base_coll_args_t *coll_args,
     ucc_tl_ucp_team_t *tl_team = ucc_derived_of(team, ucc_tl_ucp_team_t);
     ucc_rank_t         size    = UCC_TL_TEAM_SIZE(tl_team);
     ucc_kn_radix_t     radix;
-
     radix = ucc_min(UCC_TL_UCP_TEAM_LIB(tl_team)->cfg.allgather_kn_radix, size);
     return ucc_tl_ucp_allgather_knomial_init_r(coll_args, team, task_h, radix);
 }
diff --git a/src/components/tl/ucp/allgather/allgather_neighbor.c b/src/components/tl/ucp/allgather/allgather_neighbor.c
index 534c197e4e..6e8461540a 100644
--- a/src/components/tl/ucp/allgather/allgather_neighbor.c
+++ b/src/components/tl/ucp/allgather/allgather_neighbor.c
@@ -145,18 +145,26 @@ ucc_status_t ucc_tl_ucp_allgather_neighbor_start(ucc_coll_task_t *coll_task)
     ucc_rank_t         neighbor;
     void              *tmprecv, *tmpsend;
 
+    
     UCC_TL_UCP_PROFILE_REQUEST_EVENT(coll_task, "ucp_allgather_neighbor_start",
                                      0);
     ucc_tl_ucp_task_reset(task, UCC_INPROGRESS);
 
+    int use_cuda = UCC_TL_UCP_TEAM_LIB(team)->cfg.allgather_use_cuda;
+
     if (!UCC_IS_INPLACE(TASK_ARGS(task))) {
-        status = ucc_mc_memcpy(PTR_OFFSET(rbuf, data_size * trank), sbuf,
+        if (use_cuda) {
+            status = ucc_mc_memcpy(PTR_OFFSET(rbuf, data_size * trank), sbuf,
                                data_size, rmem, smem);
-        if (ucc_unlikely(UCC_OK != status)) {
-            return status;
+            if (ucc_unlikely(UCC_OK != status)) {
+                return status;
+            }
+        } else {
+            /* Loopback */
+            UCPCHECK_GOTO(ucc_tl_ucp_send_nb(sbuf, data_size, smem, trank, team, task),task, err);
+            UCPCHECK_GOTO(ucc_tl_ucp_recv_nb(PTR_OFFSET(rbuf, data_size * trank), data_size, rmem, trank, team, task),task, err);
         }
     }
-
     if (trank % 2) {
         neighbor = (trank - 1 + tsize) % tsize;
     } else {
@@ -175,4 +183,6 @@ ucc_status_t ucc_tl_ucp_allgather_neighbor_start(ucc_coll_task_t *coll_task)
         task, out);
 out:
     return ucc_progress_queue_enqueue(UCC_TL_CORE_CTX(team)->pq, &task->super);
+err:
+    return task->super.status; 
 }
diff --git a/src/components/tl/ucp/allgather/allgather_ring.c b/src/components/tl/ucp/allgather/allgather_ring.c
index 07178aea25..6816a58d48 100644
--- a/src/components/tl/ucp/allgather/allgather_ring.c
+++ b/src/components/tl/ucp/allgather/allgather_ring.c
@@ -47,16 +47,24 @@ void ucc_tl_ucp_allgather_ring_progress(ucc_coll_task_t *coll_task)
     if (UCC_INPROGRESS == ucc_tl_ucp_test(task)) {
         return;
     }
+
     sendto   = ucc_ep_map_eval(task->subset.map, (trank + 1) % tsize);
     recvfrom = ucc_ep_map_eval(task->subset.map, (trank - 1 + tsize) % tsize);
+    
+    
+    uint32_t use_cuda = UCC_TL_UCP_TEAM_LIB(team)->cfg.allgather_use_cuda;
+    int iter = use_cuda ? tsize - 1 : tsize;
+
+    while (task->tagged.send_posted < iter) {
+        
+        step = use_cuda ? task->tagged.send_posted : task->tagged.send_posted - 1;
 
-    while (task->tagged.send_posted < tsize - 1) {
-        step = task->tagged.send_posted;
         sblock = task->allgather_ring.get_send_block(&task->subset, trank,
                                                      tsize, step);
         rblock = task->allgather_ring.get_recv_block(&task->subset, trank,
                                                      tsize, step);
         buf = PTR_OFFSET(rbuf, sblock * data_size);
+
         UCPCHECK_GOTO(
             ucc_tl_ucp_send_nb(buf, data_size, rmem, sendto, team, task),
             task, out);
@@ -64,6 +72,7 @@ void ucc_tl_ucp_allgather_ring_progress(ucc_coll_task_t *coll_task)
         UCPCHECK_GOTO(
             ucc_tl_ucp_recv_nb(buf, data_size, rmem, recvfrom, team, task),
             task, out);
+        
         if (UCC_INPROGRESS == ucc_tl_ucp_test(task)) {
             return;
         }
@@ -93,17 +102,26 @@ ucc_status_t ucc_tl_ucp_allgather_ring_start(ucc_coll_task_t *coll_task)
     UCC_TL_UCP_PROFILE_REQUEST_EVENT(coll_task, "ucp_allgather_ring_start", 0);
     ucc_tl_ucp_task_reset(task, UCC_INPROGRESS);
 
+    int use_cuda = UCC_TL_UCP_TEAM_LIB(team)->cfg.allgather_use_cuda;
+    
     if (!UCC_IS_INPLACE(TASK_ARGS(task))) {
-        block = task->allgather_ring.get_send_block(&task->subset, trank, tsize,
-                                                    0);
-        status = ucc_mc_memcpy(PTR_OFFSET(rbuf, data_size * block),
+        block = task->allgather_ring.get_send_block(&task->subset, trank, tsize, 0);
+        if (use_cuda) {
+            status = ucc_mc_memcpy(PTR_OFFSET(rbuf, data_size * block),
                                sbuf, data_size, rmem, smem);
-        if (ucc_unlikely(UCC_OK != status)) {
-            return status;
+            if (ucc_unlikely(UCC_OK != status)) {
+                return status;
+            }
+        } else {
+            /* Loopback */
+            ucc_rank_t rank = ucc_ep_map_eval(task->subset.map, trank);
+            UCPCHECK_GOTO(ucc_tl_ucp_send_nb(sbuf, data_size, smem, rank, team, task),task, out);
+            UCPCHECK_GOTO(ucc_tl_ucp_recv_nb(PTR_OFFSET(rbuf, data_size * block), data_size, rmem, rank, team, task),task, out);
         }
     }
-
     return ucc_progress_queue_enqueue(UCC_TL_CORE_CTX(team)->pq, &task->super);
+out:
+    return task->super.status;
 }
 
 ucc_status_t ucc_tl_ucp_allgather_ring_init_common(ucc_tl_ucp_task_t *task)
@@ -119,6 +137,7 @@ ucc_status_t ucc_tl_ucp_allgather_ring_init_common(ucc_tl_ucp_task_t *task)
     if (!(task->flags & UCC_TL_UCP_TASK_FLAG_SUBSET)) {
         if (team->cfg.use_reordering) {
             sbgp = ucc_topo_get_sbgp(team->topo, UCC_SBGP_FULL_HOST_ORDERED);
+            //printf("reordering: rank %d chenged to %d\n", (int)task->subset.myrank, (int)sbgp->group_rank);
             task->subset.myrank = sbgp->group_rank;
             task->subset.map    = sbgp->map;
         }
@@ -147,4 +166,4 @@ ucc_status_t ucc_tl_ucp_allgather_ring_init(ucc_base_coll_args_t *coll_args,
     }
     *task_h = &task->super;
     return UCC_OK;
-}
+}
\ No newline at end of file
diff --git a/src/components/tl/ucp/allgather/allgather_sparbit.c b/src/components/tl/ucp/allgather/allgather_sparbit.c
index 0edfc4d4a3..20c60e8c32 100644
--- a/src/components/tl/ucp/allgather/allgather_sparbit.c
+++ b/src/components/tl/ucp/allgather/allgather_sparbit.c
@@ -130,13 +130,22 @@ ucc_status_t ucc_tl_ucp_allgather_sparbit_start(ucc_coll_task_t *coll_task)
     task->allgather_sparbit.i             = 0; // setup iteration
     task->allgather_sparbit.data_expected = 1;
 
+    int use_cuda = UCC_TL_UCP_TEAM_LIB(team)->cfg.allgather_use_cuda;
+
     if (!UCC_IS_INPLACE(TASK_ARGS(task))) {
-        status = ucc_mc_memcpy(PTR_OFFSET(rbuf, data_size * trank), sbuf,
+        if (use_cuda) {
+            status = ucc_mc_memcpy(PTR_OFFSET(rbuf, data_size * trank), sbuf,
                                data_size, rmem, smem);
-        if (ucc_unlikely(UCC_OK != status)) {
-            return status;
+            if (ucc_unlikely(UCC_OK != status)) {
+                return status;
+            }
+        } else {
+            /* Loopback */
+            UCPCHECK_GOTO(ucc_tl_ucp_send_nb(sbuf, data_size, smem, trank, team, task),task, out);
+            UCPCHECK_GOTO(ucc_tl_ucp_recv_nb(PTR_OFFSET(rbuf, data_size * trank), data_size, rmem, trank, team, task),task, out);
         }
     }
-
     return ucc_progress_queue_enqueue(UCC_TL_CORE_CTX(team)->pq, &task->super);
+out:
+    return task->super.status;
 }
diff --git a/src/components/tl/ucp/tl_ucp.c b/src/components/tl/ucp/tl_ucp.c
index 7db99bdaf2..b1be17e1f8 100644
--- a/src/components/tl/ucp/tl_ucp.c
+++ b/src/components/tl/ucp/tl_ucp.c
@@ -140,6 +140,10 @@ ucc_config_field_t ucc_tl_ucp_lib_config_table[] = {
      ucc_offsetof(ucc_tl_ucp_lib_config_t, allgather_kn_radix),
      UCC_CONFIG_TYPE_UINT},
 
+     {"ALLGATHER_USE_CUDA", "1", "Flag weather to use mc cuda copy",
+     ucc_offsetof(ucc_tl_ucp_lib_config_t, allgather_use_cuda),
+     UCC_CONFIG_TYPE_UINT},
+
     {"BCAST_KN_RADIX", "4", "Radix of the recursive-knomial bcast algorithm",
      ucc_offsetof(ucc_tl_ucp_lib_config_t, bcast_kn_radix),
      UCC_CONFIG_TYPE_UINT},
diff --git a/src/components/tl/ucp/tl_ucp.h b/src/components/tl/ucp/tl_ucp.h
index 3c439f4ae5..517d4dba3b 100644
--- a/src/components/tl/ucp/tl_ucp.h
+++ b/src/components/tl/ucp/tl_ucp.h
@@ -45,6 +45,7 @@ extern ucc_tl_ucp_iface_t ucc_tl_ucp;
 typedef struct ucc_tl_ucp_lib_config {
     ucc_tl_lib_config_t      super;
     uint32_t                 kn_radix;
+    uint32_t                 allgather_use_cuda;
     uint32_t                 fanin_kn_radix;
     uint32_t                 fanout_kn_radix;
     uint32_t                 barrier_kn_radix;
diff --git a/src/components/tl/ucp/tl_ucp_coll.h b/src/components/tl/ucp/tl_ucp_coll.h
index 2769244d39..5f7a16e49f 100644
--- a/src/components/tl/ucp/tl_ucp_coll.h
+++ b/src/components/tl/ucp/tl_ucp_coll.h
@@ -270,6 +270,7 @@ typedef struct ucc_tl_ucp_task {
         } alltoall_bruck;
         char                        plugin_data[UCC_TL_UCP_TASK_PLUGIN_MAX_DATA];
     };
+    //int count;
 } ucc_tl_ucp_task_t;
 
 typedef struct ucc_tl_ucp_schedule {
diff --git a/src/components/tl/ucp/tl_ucp_lib.c b/src/components/tl/ucp/tl_ucp_lib.c
index 9a724abff9..7902ddf913 100644
--- a/src/components/tl/ucp/tl_ucp_lib.c
+++ b/src/components/tl/ucp/tl_ucp_lib.c
@@ -26,6 +26,7 @@ UCC_CLASS_INIT_FUNC(ucc_tl_ucp_lib_t, const ucc_base_lib_params_t *params,
     if (UCC_OK != status) {
         return status;
     }
+    //printf("\n ------- use_cuda tl_ucp_lib.c:29 = %u ----------\n", self->cfg.allgather_use_cuda);
 
     if (tl_ucp_config->kn_radix > 0) {
         self->cfg.barrier_kn_radix        = tl_ucp_config->kn_radix;
diff --git a/src/components/tl/ucp/tl_ucp_service_coll.c b/src/components/tl/ucp/tl_ucp_service_coll.c
index bf16cf00d7..6176a0f643 100644
--- a/src/components/tl/ucp/tl_ucp_service_coll.c
+++ b/src/components/tl/ucp/tl_ucp_service_coll.c
@@ -31,6 +31,7 @@ static ucc_rank_t ucc_tl_ucp_service_ring_get_recv_block(ucc_subset_t *subset,
 
 static ucc_status_t ucc_tl_ucp_service_coll_start_executor(ucc_coll_task_t *task)
 {
+    ucc_debug("<==================== install/ucc/src/components/tl/ucp/tl_ucp_service_coll.c:34 start executer ====================>");
     ucc_ee_executor_params_t eparams;
     ucc_status_t status;
 
@@ -143,6 +144,7 @@ ucc_status_t ucc_tl_ucp_service_allgather(ucc_base_team_t *team, void *sbuf,
                                           ucc_subset_t      subset,
                                           ucc_coll_task_t **task_p)
 {
+    ucc_debug("<==================== install/ucc/src/components/tl/ucp/tl_ucp_service_coll.c:146 ====================>");
     ucc_tl_ucp_team_t   *tl_team  = ucc_derived_of(team, ucc_tl_ucp_team_t);
     ucc_tl_ucp_task_t   *task     = ucc_tl_ucp_get_task(tl_team);
     uint32_t             npolls   =
@@ -167,6 +169,7 @@ ucc_status_t ucc_tl_ucp_service_allgather(ucc_base_team_t *team, void *sbuf,
     ucc_status_t       status;
 
     status               = ucc_coll_task_init(&task->super, &bargs, team);
+    ucc_debug("<==================== install/ucc/src/components/tl/ucp/tl_ucp_service_coll.c:171 ====================>");
     if (status != UCC_OK) {
         goto free_task;
     }
diff --git a/src/ucc/api/ucc.h b/src/ucc/api/ucc.h
index 3257c79896..6b0c13ade5 100644
--- a/src/ucc/api/ucc.h
+++ b/src/ucc/api/ucc.h
@@ -1880,6 +1880,8 @@ typedef struct ucc_coll_args {
         int64_t  stride;
         uint64_t size;
     } active_set;
+
+  
 } ucc_coll_args_t;
 
 /**