diff --git a/io/epoll.cpp b/io/epoll.cpp
index 16f18c66..d6656185 100644
--- a/io/epoll.cpp
+++ b/io/epoll.cpp
@@ -271,6 +271,21 @@ class EventEngineEPoll : public MasterEventEngine, public CascadingEventEngine {
         if (ret < 0) LOG_ERROR_RETURN(0, -1, "failed to add event interest");
         // if timeout is just simple 0, wait for a tiny little moment
         // so that events can be collect.
+        if (!timeout) {
+            ret = -1;
+            wait_for_events(
+                0,
+                [&](void* data) __INLINE__ {
+                    if ((thread*)data == CURRENT) {
+                        ret = 0;
+                    } else {
+                        thread_interrupt((thread*)data, EOK);
+                    }
+                },
+                [&]() __INLINE__ { return true; });
+            if (ret < 0) errno = ETIMEDOUT;
+            return ret;
+        }
         ret = thread_usleep(timeout ? timeout : 10);
         ERRNO err;
         if (ret == -1 && err.no == EOK) {
diff --git a/io/kqueue.cpp b/io/kqueue.cpp
index 1272b3c3..8b63f066 100644
--- a/io/kqueue.cpp
+++ b/io/kqueue.cpp
@@ -77,21 +77,8 @@ class KQueue : public MasterEventEngine, public CascadingEventEngine {
         return 0;
     }
 
-    int wait_for_fd(int fd, uint32_t interests, uint64_t timeout) override {
-        short ev = (interests == EVENT_READ) ? EVFILT_READ : EVFILT_WRITE;
-        enqueue(fd, ev, EV_ADD | EV_ONESHOT, 0, CURRENT);
-        int ret = thread_usleep(timeout ? timeout : 10);
-        ERRNO err;
-        if (ret == -1 && err.no == EOK) {
-            return 0;  // event arrived
-        }
-
-        // enqueue(fd, ev, EV_DELETE, 0, CURRENT, true); // immediately
-        errno = (ret == 0) ? ETIMEDOUT : err.no;
-        return -1;
-    }
-
-    ssize_t wait_and_fire_events(uint64_t timeout = -1) override {
+    template<typename EVCB>
+    ssize_t do_wait_and_fire_events(uint64_t timeout, EVCB&& event_callback) {
         ssize_t nev = 0;
         struct timespec tm;
         tm.tv_sec = timeout / 1000 / 1000;
@@ -106,8 +93,7 @@ class KQueue : public MasterEventEngine, public CascadingEventEngine {
         nev += ret;
         for (int i = 0; i < ret; ++i) {
             if (_events[i].filter == EVFILT_USER) continue;
-            auto th = (thread*) _events[i].udata;
-            if (th) thread_interrupt(th, EOK);
+            event_callback(_events[i].udata);
         }
         if (ret == (int) LEN(_events)) {  // there may be more events
             tm.tv_sec = tm.tv_nsec = 0;
@@ -116,6 +102,40 @@ class KQueue : public MasterEventEngine, public CascadingEventEngine {
         return nev;
     }
 
+    int wait_for_fd(int fd, uint32_t interests, uint64_t timeout) override {
+        short ev = (interests == EVENT_READ) ? EVFILT_READ : EVFILT_WRITE;
+        enqueue(fd, ev, EV_ADD | EV_ONESHOT, 0, CURRENT);
+        if (!timeout) {
+            int ret = -1;
+            do_wait_and_fire_events(0, [&](void* data) { 
+                            auto th = (thread*) _events[i].udata;
+                            if (th == CURRENT)
+                                ret = 0;
+                            else if (th)
+                                thread_interrupt(th, EOK);
+
+             });
+             if (ret < 0) errno = ETIMEDOUT;
+             return ret;
+        }
+        int ret = thread_usleep(timeout);
+        ERRNO err;
+        if (ret == -1 && err.no == EOK) {
+            return 0;  // event arrived
+        }
+
+        // enqueue(fd, ev, EV_DELETE, 0, CURRENT, true); // immediately
+        errno = (ret == 0) ? ETIMEDOUT : err.no;
+        return -1;
+    }
+
+    ssize_t wait_and_fire_events(uint64_t timeout = -1) override {
+        return do_wait_and_fire_events(timeout, [&]{
+            auto th = (thread*)_events[i].udata;
+            if (th) thread_interrupt(th, EOK);
+        };
+    }
+
     int cancel_wait() override {
         enqueue(_kq, EVFILT_USER, EV_ONESHOT, NOTE_TRIGGER, nullptr, true);
         return 0;