fix $request_time for subrequests
diff --git a/src/http/ngx_http_core_module.c b/src/http/ngx_http_core_module.c
index b4b86a7..f7bb55d 100644
--- a/src/http/ngx_http_core_module.c
+++ b/src/http/ngx_http_core_module.c
@@ -2152,6 +2152,7 @@
     ngx_str_t *uri, ngx_str_t *args, ngx_http_request_t **psr,
     ngx_http_post_subrequest_t *ps, ngx_uint_t flags)
 {
+    ngx_time_t                    *tp;
     ngx_connection_t              *c;
     ngx_http_request_t            *sr;
     ngx_http_core_srv_conf_t      *cscf;
@@ -2264,6 +2265,10 @@
 
     sr->uri_changes = NGX_HTTP_MAX_URI_CHANGES + 1;
 
+    tp = ngx_timeofday();
+    r->start_sec = tp->sec;
+    r->start_msec = tp->msec;
+
     r->main->subrequests++;
     r->main->count++;