diff --git a/src/pm/hydra/lib/pmiserv_common.c b/src/pm/hydra/lib/pmiserv_common.c
index 9db6e0864e7..eae6ffe7c5a 100644
--- a/src/pm/hydra/lib/pmiserv_common.c
+++ b/src/pm/hydra/lib/pmiserv_common.c
@@ -85,14 +85,16 @@ HYD_status HYD_pmcd_pmi_send(int fd, struct PMIU_cmd *pmi, struct HYD_pmcd_hdr *
     goto fn_exit;
 }
 
-HYD_status HYD_pmcd_pmi_allocate_kvs(struct HYD_pmcd_pmi_kvs **kvs)
+HYD_status HYD_pmcd_pmi_allocate_kvs(struct HYD_kvs **kvs)
 {
     HYD_status status = HYD_SUCCESS;
     HYDU_FUNC_ENTER();
 
-    HYDU_MALLOC_OR_JUMP(*kvs, struct HYD_pmcd_pmi_kvs *, sizeof(struct HYD_pmcd_pmi_kvs), status);
+    HYDU_MALLOC_OR_JUMP(*kvs, struct HYD_kvs *, sizeof(struct HYD_kvs), status);
     (*kvs)->key_pair = NULL;
-    (*kvs)->tail = NULL;
+    (*kvs)->iter_end = NULL;
+    (*kvs)->iter_cur = NULL;
+    (*kvs)->iter_new_only = false;
 
   fn_exit:
     HYDU_FUNC_EXIT();
@@ -102,9 +104,9 @@ HYD_status HYD_pmcd_pmi_allocate_kvs(struct HYD_pmcd_pmi_kvs **kvs)
     goto fn_exit;
 }
 
-void HYD_pmcd_free_pmi_kvs_list(struct HYD_pmcd_pmi_kvs *kvs_list)
+void HYD_pmcd_free_pmi_kvs_list(struct HYD_kvs *kvs_list)
 {
-    struct HYD_pmcd_pmi_kvs_pair *key_pair, *tmp;
+    struct HYD_kvs_pair *key_pair, *tmp;
 
     HYDU_FUNC_ENTER();
 
@@ -119,16 +121,33 @@ void HYD_pmcd_free_pmi_kvs_list(struct HYD_pmcd_pmi_kvs *kvs_list)
     HYDU_FUNC_EXIT();
 }
 
-HYD_status HYD_pmcd_pmi_add_kvs(const char *key, const char *val, struct HYD_pmcd_pmi_kvs *kvs,
-                                int *ret)
+HYD_status HYD_kvs_find(struct HYD_kvs *kvs_list, const char *key, const char **val, int *found)
 {
-    struct HYD_pmcd_pmi_kvs_pair *key_pair;
+    HYDU_FUNC_ENTER();
+    *found = 0;
+
+    struct HYD_kvs_pair *run;
+    for (run = kvs_list->key_pair; run; run = run->next) {
+        if (!strcmp(run->key, key)) {
+            *val = run->val;
+            *found = 1;
+            goto fn_exit;
+        }
+    }
+
+  fn_exit:
+    HYDU_FUNC_EXIT();
+    return HYD_SUCCESS;
+}
+
+HYD_status HYD_pmcd_pmi_add_kvs(const char *key, const char *val, struct HYD_kvs * kvs, int *ret)
+{
+    struct HYD_kvs_pair *key_pair;
     HYD_status status = HYD_SUCCESS;
 
     HYDU_FUNC_ENTER();
 
-    HYDU_MALLOC_OR_JUMP(key_pair, struct HYD_pmcd_pmi_kvs_pair *,
-                        sizeof(struct HYD_pmcd_pmi_kvs_pair), status);
+    HYDU_MALLOC_OR_JUMP(key_pair, struct HYD_kvs_pair *, sizeof(struct HYD_kvs_pair), status);
     snprintf(key_pair->key, PMI_MAXKEYLEN, "%s", key);
     snprintf(key_pair->val, PMI_MAXVALLEN, "%s", val);
     key_pair->next = NULL;
@@ -137,25 +156,18 @@ HYD_status HYD_pmcd_pmi_add_kvs(const char *key, const char *val, struct HYD_pmc
 
     if (kvs->key_pair == NULL) {
         kvs->key_pair = key_pair;
-        kvs->tail = key_pair;
     } else {
 #ifdef PMI_KEY_CHECK
-        struct HYD_pmcd_pmi_kvs_pair *run, *last;
-
-        for (run = kvs->key_pair; run; run = run->next) {
-            if (!strcmp(run->key, key_pair->key)) {
-                /* duplicate key found */
-                *ret = -1;
-                goto fn_fail;
-            }
-            last = run;
+        const char *dummy_val;
+        int found;
+        HYD_kvs_find(kvs, key, &val, &found);
+        if (found) {
+            *ret = -1;
+            goto fn_fail;
         }
-        /* Add key_pair to end of list. */
-        last->next = key_pair;
-#else
-        kvs->tail->next = key_pair;
-        kvs->tail = key_pair;
 #endif
+        key_pair->next = kvs->key_pair;
+        kvs->key_pair = key_pair;
     }
 
   fn_exit:
@@ -167,6 +179,35 @@ HYD_status HYD_pmcd_pmi_add_kvs(const char *key, const char *val, struct HYD_pmc
     goto fn_exit;
 }
 
+void HYD_kvs_iter_begin(struct HYD_kvs *kvs_list, bool new_only)
+{
+    kvs_list->iter_begin = kvs_list->key_pair;
+    kvs_list->iter_cur = kvs_list->iter_begin;
+    kvs_list->iter_new_only = new_only;
+}
+
+void HYD_kvs_iter_end(struct HYD_kvs *kvs_list)
+{
+    if (kvs_list->iter_new_only) {
+        kvs_list->iter_end = kvs_list->iter_begin;
+    }
+    kvs_list->iter_begin = NULL;
+    kvs_list->iter_new_only = false;
+}
+
+bool HYD_kvs_iter_next(struct HYD_kvs *kvs_list, const char **key, const char **val)
+{
+    if (kvs_list->iter_cur == NULL ||
+        (kvs_list->iter_new_only && kvs_list->iter_cur == kvs_list->iter_end)) {
+        return false;
+    } else {
+        *key = kvs_list->iter_cur->key;
+        *val = kvs_list->iter_cur->val;
+        kvs_list->iter_cur = kvs_list->iter_cur->next;
+        return true;
+    }
+}
+
 const char *HYD_pmcd_cmd_name(int cmd)
 {
     switch (cmd) {
diff --git a/src/pm/hydra/lib/pmiserv_common.h b/src/pm/hydra/lib/pmiserv_common.h
index b5dc1b01ac5..4fab9a5267b 100644
--- a/src/pm/hydra/lib/pmiserv_common.h
+++ b/src/pm/hydra/lib/pmiserv_common.h
@@ -16,15 +16,19 @@
 #define PMI_MAXVALLEN    (1024) /* max length of value in keyval space */
 #define PMI_MAXKVSLEN    (256)  /* max length of various names */
 
-struct HYD_pmcd_pmi_kvs_pair {
+struct HYD_kvs_pair {
     char key[PMI_MAXKEYLEN];
     char val[PMI_MAXVALLEN];
-    struct HYD_pmcd_pmi_kvs_pair *next;
+    struct HYD_kvs_pair *next;
 };
 
-struct HYD_pmcd_pmi_kvs {
-    struct HYD_pmcd_pmi_kvs_pair *key_pair;
-    struct HYD_pmcd_pmi_kvs_pair *tail;
+struct HYD_kvs {
+    struct HYD_kvs_pair *key_pair;
+    /* iter fields used for HYD_pmiserv_bcast_keyvals */
+    struct HYD_kvs_pair *iter_end;
+    struct HYD_kvs_pair *iter_begin;
+    struct HYD_kvs_pair *iter_cur;
+    bool iter_new_only;
 };
 
 /* init header proxy send to server upon connection */
@@ -34,10 +38,13 @@ struct HYD_pmcd_init_hdr {
     int proxy_id;
 };
 
-HYD_status HYD_pmcd_pmi_allocate_kvs(struct HYD_pmcd_pmi_kvs **kvs);
-void HYD_pmcd_free_pmi_kvs_list(struct HYD_pmcd_pmi_kvs *kvs_list);
-HYD_status HYD_pmcd_pmi_add_kvs(const char *key, const char *val, struct HYD_pmcd_pmi_kvs *kvs,
-                                int *ret);
+HYD_status HYD_pmcd_pmi_allocate_kvs(struct HYD_kvs **kvs);
+void HYD_pmcd_free_pmi_kvs_list(struct HYD_kvs *kvs_list);
+HYD_status HYD_kvs_find(struct HYD_kvs *kvs_list, const char *key, const char **val, int *found);
+HYD_status HYD_pmcd_pmi_add_kvs(const char *key, const char *val, struct HYD_kvs *kvs, int *ret);
+void HYD_kvs_iter_begin(struct HYD_kvs *kvs_list, bool new_only);
+void HYD_kvs_iter_end(struct HYD_kvs *kvs_list);
+bool HYD_kvs_iter_next(struct HYD_kvs *kvs_list, const char **key, const char **val);
 
 /* ---- struct HYD_pmcd_hdr ---- */
 
diff --git a/src/pm/hydra/mpiexec/pmiserv_kvs.c b/src/pm/hydra/mpiexec/pmiserv_kvs.c
index ac98204623f..1cebeb8a19b 100644
--- a/src/pm/hydra/mpiexec/pmiserv_kvs.c
+++ b/src/pm/hydra/mpiexec/pmiserv_kvs.c
@@ -56,14 +56,7 @@ HYD_status HYD_pmiserv_kvs_get(struct HYD_proxy *proxy, int process_fd, int pgid
         found = 1;
         val = pg_scratch->dead_processes;
     } else {
-        struct HYD_pmcd_pmi_kvs_pair *run;
-        for (run = pg_scratch->kvs->key_pair; run; run = run->next) {
-            if (strcmp(run->key, key) == 0) {
-                found = 1;
-                val = run->val;
-                break;
-            }
-        }
+        HYD_kvs_find(pg_scratch->kvs, key, &val, &found);
     }
 
     if (!found && sync) {
diff --git a/src/pm/hydra/mpiexec/pmiserv_pmi.c b/src/pm/hydra/mpiexec/pmiserv_pmi.c
index 37d4b966942..8782591908e 100644
--- a/src/pm/hydra/mpiexec/pmiserv_pmi.c
+++ b/src/pm/hydra/mpiexec/pmiserv_pmi.c
@@ -30,54 +30,45 @@ HYD_status HYD_pmiserv_pmi_reply(struct HYD_proxy * proxy, int process_fd, struc
 
 HYD_status HYD_pmiserv_bcast_keyvals(struct HYD_proxy * proxy, int process_fd)
 {
-    int keyval_count, arg_count, j;
-    struct HYD_pmcd_pmi_kvs_pair *run;
-    struct HYD_pg *pg;
-    struct HYD_pmcd_pmi_pg_scratch *pg_scratch;
     HYD_status status = HYD_SUCCESS;
-
     HYDU_FUNC_ENTER();
 
+    struct HYD_pg *pg;
+    struct HYD_pmcd_pmi_pg_scratch *pg_scratch;
     pg = PMISERV_pg_by_id(proxy->pgid);
     pg_scratch = (struct HYD_pmcd_pmi_pg_scratch *) pg->pg_scratch;
 
-    /* find the number of keyvals */
-    keyval_count = 0;
-    for (run = pg_scratch->kvs->key_pair; run; run = run->next)
-        keyval_count++;
-
-    keyval_count -= pg_scratch->keyval_dist_count;
-
-    if (keyval_count) {
-        struct PMIU_cmd pmi;
-        PMIU_msg_set_query(&pmi, PMIU_WIRE_V1, PMIU_CMD_KVSCACHE, false /* not static */);
-        arg_count = 1;
-        for (run = pg_scratch->kvs->key_pair, j = 0; run; run = run->next, j++) {
-            if (j < pg_scratch->keyval_dist_count)
-                continue;
-
-            PMIU_cmd_add_str(&pmi, run->key, run->val);
-
-            arg_count++;
-            if (arg_count >= MAX_PMI_ARGS) {
-                pg_scratch->keyval_dist_count += (arg_count - 1);
-                for (int i = 0; i < pg->proxy_count; i++) {
-                    status = HYD_pmiserv_pmi_reply(&pg->proxy_list[i], process_fd, &pmi);
-                    HYDU_ERR_POP(status, "error writing PMI line\n");
-                }
+    struct PMIU_cmd pmi;
+    int arg_count = 0, num_total = 0;
 
+    const char *key, *val;
+    HYD_kvs_iter_begin(pg_scratch->kvs, true);
+    while (true) {
+        bool has_next = HYD_kvs_iter_next(pg_scratch->kvs, &key, &val);
+        if (has_next) {
+            if (arg_count == 0) {
                 PMIU_msg_set_query(&pmi, PMIU_WIRE_V1, PMIU_CMD_KVSCACHE, false /* not static */);
                 arg_count = 1;
             }
+            PMIU_cmd_add_str(&pmi, key, val);
+            arg_count++;
+            num_total++;
         }
 
-        if (arg_count > 1) {
-            pg_scratch->keyval_dist_count += (arg_count - 1);
+        if (arg_count >= MAX_PMI_ARGS || (!has_next && arg_count > 1)) {
             for (int i = 0; i < pg->proxy_count; i++) {
                 status = HYD_pmiserv_pmi_reply(&pg->proxy_list[i], process_fd, &pmi);
                 HYDU_ERR_POP(status, "error writing PMI line\n");
             }
+            arg_count = 0;
         }
+
+        if (!has_next) {
+            break;
+        }
+    }
+    HYD_kvs_iter_end(pg_scratch->kvs);
+    if (num_total > 0) {
         PMIU_cmd_free_buf(&pmi);
     }
 
diff --git a/src/pm/hydra/mpiexec/pmiserv_pmi.h b/src/pm/hydra/mpiexec/pmiserv_pmi.h
index 2f356840233..83c3163c193 100644
--- a/src/pm/hydra/mpiexec/pmiserv_pmi.h
+++ b/src/pm/hydra/mpiexec/pmiserv_pmi.h
@@ -27,7 +27,7 @@ struct HYD_pmcd_pmi_pg_scratch {
     int dead_process_count;
 
     char kvsname[PMI_MAXKVSLEN];
-    struct HYD_pmcd_pmi_kvs *kvs;
+    struct HYD_kvs *kvs;
     int keyval_dist_count;      /* Number of keyvals distributed */
 };
 
diff --git a/src/pm/hydra/mpiexec/pmiserv_spawn.c b/src/pm/hydra/mpiexec/pmiserv_spawn.c
index ebdbbdd0f91..c512fd1af1b 100644
--- a/src/pm/hydra/mpiexec/pmiserv_spawn.c
+++ b/src/pm/hydra/mpiexec/pmiserv_spawn.c
@@ -17,8 +17,7 @@ static HYD_status allocate_spawn_pg(int spawner_pgid);
 static HYD_status fill_exec_params(struct HYD_exec *exec, const char *execname, int nprocs,
                                    int argcnt, const char **argv,
                                    int infonum, struct PMIU_token *infos);
-static HYD_status fill_preput_kvs(struct HYD_pmcd_pmi_kvs *kvs,
-                                  int preput_num, struct PMIU_token *infos);
+static HYD_status fill_preput_kvs(struct HYD_kvs *kvs, int preput_num, struct PMIU_token *infos);
 static HYD_status do_spawn(void);
 
 static char *get_exec_path(const char *execname, const char *path);
@@ -205,8 +204,7 @@ static HYD_status fill_exec_params(struct HYD_exec *exec, const char *execname,
     goto fn_exit;
 }
 
-static HYD_status fill_preput_kvs(struct HYD_pmcd_pmi_kvs *kvs,
-                                  int preput_num, struct PMIU_token *infos)
+static HYD_status fill_preput_kvs(struct HYD_kvs *kvs, int preput_num, struct PMIU_token *infos)
 {
     HYD_status status = HYD_SUCCESS;
 
diff --git a/src/pm/hydra/proxy/pmip.h b/src/pm/hydra/proxy/pmip.h
index 7d53b7f7b3f..c9b3f990225 100644
--- a/src/pm/hydra/proxy/pmip.h
+++ b/src/pm/hydra/proxy/pmip.h
@@ -101,7 +101,7 @@ struct pmip_pg {
     struct HYD_exec *exec_list;
 
     /* This is for PMI-2 info-putnodeattr. Should it be per-node or per pg? */
-    struct HYD_pmcd_pmi_kvs *kvs;
+    struct HYD_kvs *kvs;
 
     /* PMI-1 caches server kvs locally */
     struct cache_put_elem cache_put;
diff --git a/src/pm/hydra/proxy/pmip_pmi.c b/src/pm/hydra/proxy/pmip_pmi.c
index cc4ffbe3095..b3b90df66c2 100644
--- a/src/pm/hydra/proxy/pmip_pmi.c
+++ b/src/pm/hydra/proxy/pmip_pmi.c
@@ -513,7 +513,8 @@ HYD_status fn_keyval_cache(struct pmip_pg *pg, struct PMIU_cmd *pmi)
     int i;
     for (i = 0; i < pg->num_elems; i++) {
         struct cache_elem *elem = pg->cache_get + i;
-        HASH_ADD_STR(pg->hash_get, key, elem, MPL_MEM_PM);
+        struct cache_elem *replaced;
+        HASH_REPLACE_STR(pg->hash_get, key, elem, replaced, MPL_MEM_PM);
     }
     for (; i < pg->num_elems + num_tokens; i++) {
         struct cache_elem *elem = pg->cache_get + i;
@@ -521,7 +522,8 @@ HYD_status fn_keyval_cache(struct pmip_pg *pg, struct PMIU_cmd *pmi)
         HYDU_ERR_CHKANDJUMP(status, NULL == elem->key, HYD_INTERNAL_ERROR, "%s", "");
         elem->val = MPL_strdup(tokens[i - pg->num_elems].val);
         HYDU_ERR_CHKANDJUMP(status, NULL == elem->val, HYD_INTERNAL_ERROR, "%s", "");
-        HASH_ADD_STR(pg->hash_get, key, elem, MPL_MEM_PM);
+        struct cache_elem *replaced;
+        HASH_REPLACE_STR(pg->hash_get, key, elem, replaced, MPL_MEM_PM);
     }
     pg->num_elems += num_tokens;
 
@@ -672,17 +674,9 @@ HYD_status fn_info_getnodeattr(struct pmip_downstream *p, struct PMIU_cmd *pmi)
     /* if a predefined value is not found, we let the code fall back
      * to regular search and return an error to the client */
 
+    const char *val;
     int found;
-    found = 0;
-
-    /* FIXME: wrap it in e.g. HYD_pmcd_pmi_find_kvs */
-    struct HYD_pmcd_pmi_kvs_pair *run;
-    for (run = PMIP_pg_from_downstream(p)->kvs->key_pair; run; run = run->next) {
-        if (!strcmp(run->key, key)) {
-            found = 1;
-            break;
-        }
-    }
+    HYD_kvs_find(PMIP_pg_from_downstream(p)->kvs, key, &val, &found);
 
     if (!found && wait) {
         status = HYD_pmcd_pmi_v2_queue_req(p, pmi, key);
@@ -692,8 +686,7 @@ HYD_status fn_info_getnodeattr(struct pmip_downstream *p, struct PMIU_cmd *pmi)
 
     struct PMIU_cmd pmi_response;
     if (found) {
-        pmi_errno =
-            PMIU_msg_set_response_getnodeattr(pmi, &pmi_response, is_static, run->val, true);
+        pmi_errno = PMIU_msg_set_response_getnodeattr(pmi, &pmi_response, is_static, val, true);
     } else {
         pmi_errno = PMIU_msg_set_response_fail(pmi, &pmi_response, is_static, 1, "not_found");
     }
diff --git a/src/util/mpir_pmi.c b/src/util/mpir_pmi.c
index 1d37e78ed0f..7753288d7ac 100644
--- a/src/util/mpir_pmi.c
+++ b/src/util/mpir_pmi.c
@@ -105,6 +105,7 @@ static char *pmi_kvs_name;
 #elif defined USE_PMI2_API
 static char *pmi_jobid;
 #elif defined USE_PMIX_API
+static int pmix_init_count = 0;
 static pmix_proc_t pmix_proc;
 static pmix_proc_t pmix_wcproc;
 #endif
@@ -119,6 +120,7 @@ static void MPIR_pmi_finalize_on_exit(void)
     PMI2_Finalize();
 #elif defined USE_PMIX_API
     PMIx_Finalize(NULL, 0);
+    pmix_init_count = 0;
 #endif
 }
 
@@ -189,20 +191,26 @@ int MPIR_pmi_init(void)
 
     pmix_value_t *pvalue = NULL;
 
-    pmi_errno = PMIx_Init(&pmix_proc, NULL, 0);
-    if (pmi_errno == PMIX_ERR_UNREACH) {
-        /* no pmi server, assume we are a singleton */
-        rank = 0;
-        size = 1;
-        goto singleton_out;
+    /* Since we only call PMIx_Finalize once at `atexit` handler, we need prevent
+     * calling PMIx_Init multiple times. */
+    pmix_init_count++;
+    if (pmix_init_count == 1) {
+        pmi_errno = PMIx_Init(&pmix_proc, NULL, 0);
+        if (pmi_errno == PMIX_ERR_UNREACH) {
+            /* no pmi server, assume we are a singleton */
+            rank = 0;
+            size = 1;
+            goto singleton_out;
+        }
+        MPIR_ERR_CHKANDJUMP1(pmi_errno != PMIX_SUCCESS, mpi_errno, MPI_ERR_OTHER,
+                             "**pmix_init", "**pmix_init %d", pmi_errno);
+
+        PMIX_PROC_CONSTRUCT(&pmix_wcproc);
+        MPL_strncpy(pmix_wcproc.nspace, pmix_proc.nspace, PMIX_MAX_NSLEN);
+        pmix_wcproc.rank = PMIX_RANK_WILDCARD;
     }
-    MPIR_ERR_CHKANDJUMP1(pmi_errno != PMIX_SUCCESS, mpi_errno, MPI_ERR_OTHER,
-                         "**pmix_init", "**pmix_init %d", pmi_errno);
 
     rank = pmix_proc.rank;
-    PMIX_PROC_CONSTRUCT(&pmix_wcproc);
-    MPL_strncpy(pmix_wcproc.nspace, pmix_proc.nspace, PMIX_MAX_NSLEN);
-    pmix_wcproc.rank = PMIX_RANK_WILDCARD;
 
     pmi_errno = PMIx_Get(&pmix_wcproc, PMIX_JOB_SIZE, NULL, 0, &pvalue);
     MPIR_ERR_CHKANDJUMP1(pmi_errno != PMIX_SUCCESS, mpi_errno, MPI_ERR_OTHER,