diff --git a/modules/ngx_http_upstream_dyups_module/ngx_http_dyups_module.c b/modules/ngx_http_upstream_dyups_module/ngx_http_dyups_module.c
index 8135ad4336..0b6f632464 100644
--- a/modules/ngx_http_upstream_dyups_module/ngx_http_dyups_module.c
+++ b/modules/ngx_http_upstream_dyups_module/ngx_http_dyups_module.c
@@ -36,6 +36,7 @@ typedef struct {
 typedef struct {
     ngx_flag_t                     enable;
     ngx_flag_t                     trylock;
+    ngx_flag_t                     serial_update;
     ngx_array_t                    dy_upstreams;/* ngx_http_dyups_srv_conf_t */
     ngx_str_t                      shm_name;
     ngx_uint_t                     shm_size;
@@ -72,6 +73,7 @@ typedef struct ngx_dyups_shctx_s {
     ngx_queue_t                          msg_queue;
     ngx_uint_t                           version;
     ngx_dyups_status_t                  *status;
+    ngx_atomic_uint_t                    flag;
 } ngx_dyups_shctx_t;
 
 
@@ -79,6 +81,7 @@ typedef struct ngx_dyups_global_ctx_s {
     ngx_event_t                          msg_timer;
     ngx_slab_pool_t                     *shpool;
     ngx_dyups_shctx_t                   *sh;
+    ngx_int_t                            workers;
 } ngx_dyups_global_ctx_t;
 
 
@@ -216,6 +219,13 @@ static ngx_command_t  ngx_http_dyups_commands[] = {
       NGX_HTTP_MAIN_CONF_OFFSET,
       offsetof(ngx_http_dyups_main_conf_t, trylock),
       NULL },
+    
+    { ngx_string("dyups_serial_update_upstream"),
+      NGX_HTTP_MAIN_CONF|NGX_CONF_TAKE1,
+      ngx_conf_set_flag_slot,
+      NGX_HTTP_MAIN_CONF_OFFSET,
+      offsetof(ngx_http_dyups_main_conf_t, serial_update),
+      NULL },
 
       ngx_null_command
 };
@@ -318,6 +328,7 @@ ngx_http_dyups_create_main_conf(ngx_conf_t *cf)
     dmcf->read_msg_timeout = NGX_CONF_UNSET_MSEC;
     dmcf->read_msg_log = NGX_CONF_UNSET;
     dmcf->trylock = NGX_CONF_UNSET;
+    dmcf->serial_update = NGX_CONF_UNSET;
 
     return dmcf;
 }
@@ -349,6 +360,10 @@ ngx_http_dyups_init_main_conf(ngx_conf_t *cf, void *conf)
     if (dmcf->shm_size == NGX_CONF_UNSET_UINT) {
         dmcf->shm_size = 2 * 1024 * 1024;
     }
+    
+    if (dmcf->serial_update == NGX_CONF_UNSET) {
+        dmcf->serial_update = 0;
+    }
 
     return ngx_http_dyups_init_shm(cf, conf);
 }
@@ -427,6 +442,7 @@ ngx_http_dyups_init_shm_zone(ngx_shm_zone_t *shm_zone, void *data)
 
     sh->version = 0;
     sh->status = NULL;
+    sh->flag = 0;
 
     return NGX_OK;
 }
@@ -562,6 +578,8 @@ ngx_http_dyups_init_process(ngx_cycle_t *cycle)
     }
 
     ngx_http_dyups_api_enable = 1;
+    
+    ngx_dyups_global_ctx.workers = ccf->worker_processes;
 
     timer = &ngx_dyups_global_ctx.msg_timer;
     ngx_memzero(timer, sizeof(ngx_event_t));
@@ -2063,9 +2081,13 @@ ngx_http_dyups_read_msg(ngx_event_t *ev)
     ngx_slab_pool_t             *shpool;
     ngx_http_dyups_srv_conf_t   *duscfs, *duscf;
     ngx_http_dyups_main_conf_t  *dmcf;
+    ngx_dyups_shctx_t           *sh;
+    ngx_uint_t                   workers;
 
     dmcf = ev->data;
     shpool = ngx_dyups_global_ctx.shpool;
+    sh = ngx_dyups_global_ctx.sh;
+    workers = ngx_dyups_global_ctx.workers;
 
     count = 0;
     s_count = 0;
@@ -2096,7 +2118,16 @@ ngx_http_dyups_read_msg(ngx_event_t *ev)
     }
 
 #if (NGX_HTTP_UPSTREAM_CHECK)
-    if (!ngx_shmtx_trylock(&shpool->mutex)) {
+    if (dmcf->serial_update) {
+        if (sh->flag % workers != ngx_worker) {
+            ngx_log_error(NGX_LOG_DEBUG, ev->log, 0,
+                      "[dyups] ngx_pid: %P, ngx_worker: %d, sh->flag: %d, not meet lock condition", ngx_pid, ngx_worker, sh->flag);
+            ngx_dyups_add_timer(ev, dmcf->read_msg_timeout);
+            return;
+        }
+        ngx_shmtx_lock(&shpool->mutex);
+    }
+    else if (!ngx_shmtx_trylock(&shpool->mutex)) {
         goto finish;
     }
 #else
@@ -2108,6 +2139,14 @@ ngx_http_dyups_read_msg(ngx_event_t *ev)
     ngx_shmtx_unlock(&shpool->mutex);
 
 #if (NGX_HTTP_UPSTREAM_CHECK)
+    if (dmcf->serial_update) {
+        ngx_atomic_fetch_add(&sh->flag, 1);
+
+        ngx_atomic_cmp_set(&sh->flag, workers, 0);
+        
+        ngx_log_error(NGX_LOG_DEBUG, ev->log, 0,
+                      "[dyups] ngx_pid: %P, ngx_worker: %d, sh->flag: %d, finish read msg under locking condition", ngx_pid, ngx_worker, sh->flag);
+    }
 finish:
 #endif
     ngx_dyups_add_timer(ev, dmcf->read_msg_timeout);
@@ -2129,6 +2168,7 @@ ngx_http_dyups_read_msg_locked(ngx_event_t *ev)
     ngx_dyups_msg_t     *msg;
     ngx_dyups_shctx_t   *sh;
     ngx_dyups_status_t  *status;
+    ngx_http_dyups_main_conf_t  *dmcf;
 
     ngx_log_debug1(NGX_LOG_DEBUG_HTTP, ev->log, 0,
                    "[dyups] read msg %P", ngx_pid);
@@ -2136,6 +2176,7 @@ ngx_http_dyups_read_msg_locked(ngx_event_t *ev)
     ccf = (ngx_core_conf_t *) ngx_get_conf(ngx_cycle->conf_ctx,
                                            ngx_core_module);
 
+    dmcf = ev->data;
     sh = ngx_dyups_global_ctx.sh;
     shpool = ngx_dyups_global_ctx.shpool;