diff --git a/src/components/tl/ucp/allgather/allgather_knomial.c b/src/components/tl/ucp/allgather/allgather_knomial.c
index 3b78c387cd..1ee1673844 100644
--- a/src/components/tl/ucp/allgather/allgather_knomial.c
+++ b/src/components/tl/ucp/allgather/allgather_knomial.c
@@ -319,15 +319,9 @@ ucc_status_t ucc_tl_ucp_allgather_knomial_init(ucc_base_coll_args_t *coll_args,
     ucc_memory_type_t  mtype   = GET_MT(&coll_args->args);
     size_t             count   = GET_TOTAL_COUNT(&coll_args->args, tsize);
     ucc_datatype_t     dtype   = GET_DT(&coll_args->args);
-    ucc_kn_radix_t     radix, cfg_radix, opt_radix;
+    ucc_kn_radix_t     radix;
 
-    opt_radix = (mtype == UCC_MEMORY_TYPE_HOST) ? tl_team->opt_radix_host :
-                                                  tl_team->opt_radix;
-
-    cfg_radix = ucc_tl_ucp_get_radix_from_range(tl_team,
-                                                count * ucc_dt_size(dtype),
-                                                mtype, p, opt_radix);
-    radix = ucc_min(cfg_radix, tsize);
+    radix = ucc_tl_ucp_get_knomial_radix(tl_team, count, dtype, mtype, p, 0);
 
     return ucc_tl_ucp_allgather_knomial_init_r(coll_args, team, task_h, radix);
 }
diff --git a/src/components/tl/ucp/allreduce/allreduce_sra_knomial.c b/src/components/tl/ucp/allreduce/allreduce_sra_knomial.c
index c20918bd28..31cef191a5 100644
--- a/src/components/tl/ucp/allreduce/allreduce_sra_knomial.c
+++ b/src/components/tl/ucp/allreduce/allreduce_sra_knomial.c
@@ -97,7 +97,7 @@ ucc_tl_ucp_allreduce_sra_knomial_frag_init(ucc_base_coll_args_t *coll_args,
     ucc_schedule_t      *schedule;
     ucc_coll_task_t     *task, *rs_task;
     ucc_status_t         status;
-    ucc_kn_radix_t       radix, cfg_radix, opt_radix;
+    ucc_kn_radix_t       radix;
     size_t               count;
 
     status = ucc_tl_ucp_get_schedule(tl_team, coll_args,
@@ -112,14 +112,7 @@ ucc_tl_ucp_allreduce_sra_knomial_frag_init(ucc_base_coll_args_t *coll_args,
         count = coll_args->args.dst.info.count;
     }
 
-    opt_radix = (mem_type == UCC_MEMORY_TYPE_HOST) ? tl_team->opt_radix_host :
-                                                     tl_team->opt_radix;
-    cfg_radix = ucc_tl_ucp_get_radix_from_range(tl_team,
-                                                count * ucc_dt_size(dtype),
-                                                mem_type, p, opt_radix);
-    radix     = ucc_knomial_pattern_get_min_radix(cfg_radix,
-                                                  UCC_TL_TEAM_SIZE(tl_team),
-                                                  count);
+    radix = ucc_tl_ucp_get_knomial_radix(tl_team, count, dtype, mem_type, p, 1);
     /* 1st step of allreduce: knomial reduce_scatter */
     UCC_CHECK_GOTO(
         ucc_tl_ucp_reduce_scatter_knomial_init_r(&args, team, &task, radix),
diff --git a/src/components/tl/ucp/tl_ucp_coll.h b/src/components/tl/ucp/tl_ucp_coll.h
index 2769244d39..eab127a606 100644
--- a/src/components/tl/ucp/tl_ucp_coll.h
+++ b/src/components/tl/ucp/tl_ucp_coll.h
@@ -508,4 +508,33 @@ ucc_tl_ucp_get_radix_from_range(ucc_tl_ucp_team_t *team,
     }
     return radix;
 }
+
+/*
+ * Get the radix for knomial patterns.
+ * If need_scratch is true, the radix is the minimum radix that can be used to fit into scratch buffer.
+ * Otherwise, the radix is the minimum radix that can be used to fit into team size.
+ */
+static inline unsigned ucc_tl_ucp_get_knomial_radix(ucc_tl_ucp_team_t *team,
+                                                    size_t             count,
+                                                    ucc_datatype_t     dtype,
+                                                    ucc_memory_type_t  mem_type,
+                                                    ucc_mrange_uint_t *p,
+                                                    int need_scratch)
+{
+    size_t msgsize = count * ucc_dt_size(dtype);
+    unsigned opt_radix, cfg_radix, radix;
+
+    opt_radix = (mem_type == UCC_MEMORY_TYPE_HOST) ? team->opt_radix_host :
+                                                    team->opt_radix;
+    cfg_radix = ucc_tl_ucp_get_radix_from_range(team, msgsize, mem_type, p,
+                                                opt_radix);
+    if (need_scratch) {
+        radix = ucc_knomial_pattern_get_min_radix(cfg_radix, UCC_TL_TEAM_SIZE(team), count);
+    } else {
+        radix = ucc_min(cfg_radix, UCC_TL_TEAM_SIZE(team));
+
+    }
+    return radix;
+}
+
 #endif