diff --git a/lib/Makefile.am b/lib/Makefile.am
index eafade5d..00af0614 100644
--- a/lib/Makefile.am
+++ b/lib/Makefile.am
@@ -7,8 +7,8 @@ libuasync_a_SOURCES = \
 	ll_queue.c \
 	debug_config.c \
 	debug_config.h \
-	timeout_heap.c \
-	timeout_heap.h \
+	twheel.c \
+	twheel.h \
 	memory_pool.c \
 	memory_pool.h \
 	sha256.c \
diff --git a/lib/timeout_heap.c b/lib/timeout_heap.c
deleted file mode 100644
index e91cf50b..00000000
--- a/lib/timeout_heap.c
+++ /dev/null
@@ -1,193 +0,0 @@
-// timeout_heap.c
-
-#include "timeout_heap.h"
-#include "debug_config.h"
-#include <stdlib.h>
-#include <stdio.h>   // For potential error printing, optional
-#include "mem.h"
-
-// Helper macros for 1-based indices
-#define PARENT(i) ((i) / 2)
-#define LEFT_CHILD(i) (2 * (i))
-#define RIGHT_CHILD(i) (2 * (i) + 1)
-
-TimeoutHeap *timeout_heap_create(size_t initial_capacity) {
-    DEBUG_DEBUG(DEBUG_CATEGORY_ETCP, "Creating TH1...");
-    TimeoutHeap *h = u_malloc(sizeof(TimeoutHeap));
-    if (!h) {
-        DEBUG_ERROR(DEBUG_CATEGORY_ETCP, "TH0 error...");
-        return NULL;
-        }
-    DEBUG_DEBUG(DEBUG_CATEGORY_ETCP, "Creating TH2...");
-    h->heap = u_malloc(sizeof(TimeoutEntry) * initial_capacity);
-    if (!h->heap) {
-        DEBUG_ERROR(DEBUG_CATEGORY_ETCP, "TH1 error...");
-        u_free(h);
-        return NULL;
-    }
-    DEBUG_DEBUG(DEBUG_CATEGORY_ETCP, "Creating TH3...");
-    h->size = 0;
-    h->capacity = initial_capacity;
-    h->freed_count = 0;
-    h->user_data = NULL;
-    h->free_callback = NULL;
-    return h;
-}
-
-
-void timeout_heap_destroy(TimeoutHeap *h) {
-    if (!h) return;
-
-    // Free all remaining data (deleted or not)
-    for (size_t i = 0; i < h->size; i++) {
-        if (h->free_callback) {
-            h->free_callback(h->user_data, h->heap[i].data);
-        }
-    }
-
-    u_free(h->heap);
-    u_free(h);
-}
-
-
-static void update_index(TimeoutHeap *h, size_t idx) {
-    if (h->heap[idx].index_ptr)
-        *h->heap[idx].index_ptr = idx;
-}
-
-static void swap_entries(TimeoutHeap *h, size_t a, size_t b) {
-    TimeoutEntry temp = h->heap[a];
-    h->heap[a] = h->heap[b];
-    h->heap[b] = temp;
-    update_index(h, a);
-    update_index(h, b);
-}
-
-static void bubble_up(TimeoutHeap *h, size_t i) {
-    // i is 1-based
-    while (i > 1 && h->heap[PARENT(i) - 1].expiration > h->heap[i - 1].expiration) {
-        swap_entries(h, PARENT(i) - 1, i - 1);
-        i = PARENT(i);
-    }
-}
-
-int timeout_heap_push(TimeoutHeap *h, TimeoutTime expiration, void *data, size_t *index_ptr) {
-    if (h->size == h->capacity) {
-        size_t new_cap = h->capacity ? h->capacity * 2 : 1;
-        TimeoutEntry *new_heap = u_realloc(h->heap, sizeof(TimeoutEntry) * new_cap);
-        if (!new_heap) return -1;  // Allocation failed
-        h->heap = new_heap;
-        h->capacity = new_cap;
-    }
-
-    // Insert at end (0-based)
-    size_t idx = h->size++;
-    h->heap[idx].expiration = expiration;
-    h->heap[idx].data = data;
-    h->heap[idx].index_ptr = index_ptr;
-    h->heap[idx].deleted = 0;
-    if (index_ptr)
-        *index_ptr = idx;
-
-    // Bubble up (1-based)
-    bubble_up(h, idx + 1);
-    return 0;
-}
-
-static void heapify_down(TimeoutHeap *h, size_t i) {
-    // i is 1-based
-    while (1) {
-        size_t smallest = i;
-        size_t left = LEFT_CHILD(i);
-        size_t right = RIGHT_CHILD(i);
-
-        if (left <= h->size && h->heap[left - 1].expiration < h->heap[smallest - 1].expiration) {
-            smallest = left;
-        }
-        if (right <= h->size && h->heap[right - 1].expiration < h->heap[smallest - 1].expiration) {
-            smallest = right;
-        }
-        if (smallest == i) break;
-
-        swap_entries(h, smallest - 1, i - 1);
-        i = smallest;
-    }
-}
-
-static void remove_root(TimeoutHeap *h) {
-    if (h->size == 0) return;
-
-    // Move last to root
-    h->heap[0] = h->heap[--h->size];
-    update_index(h, 0);
-
-    // Heapify down (1-based)
-    if (h->size > 0) {
-        heapify_down(h, 1);
-    }
-}
-
-int timeout_heap_peek(TimeoutHeap *h, TimeoutEntry *out) {
-    if (h->size == 0) return -1;
-
-    while (h->size > 0 && h->heap[0].deleted) {
-        void* data_to_free = h->heap[0].data;
-        remove_root(h);
-        if (h->free_callback) {
-            h->free_callback(h->user_data, data_to_free);
-        }
-    }
-    if (h->size == 0) return -1;
-
-    *out = h->heap[0];
-    return 0;
-}
-
-int timeout_heap_pop(TimeoutHeap *h, TimeoutEntry *out) {
-    if (h->size == 0) return -1;
-
-    while (h->size > 0 && h->heap[0].deleted) {
-        void* data_to_free = h->heap[0].data;
-        remove_root(h);
-        if (h->free_callback) {
-            h->free_callback(h->user_data, data_to_free);
-        }
-    }
-    if (h->size == 0) return -1;
-
-    *out = h->heap[0];
-    remove_root(h);
-    return 0;
-}
-
-int timeout_heap_cancel(TimeoutHeap *h, TimeoutTime expiration, void *data) {
-    for (size_t i = 0; i < h->size; ++i) {
-        if (h->heap[i].expiration == expiration && h->heap[i].data == data) {
-            h->heap[i].deleted = 1;
-            h->heap[i].expiration = 0;
-            bubble_up(h, i + 1);
-            return 0;
-        }
-    }
-    return -1;  // Not found
-}
-
-int timeout_heap_cancel_at(TimeoutHeap *h, size_t index, void *data) {
-    if (index >= h->size || h->heap[index].data != data) return -1;
-
-    h->heap[index].deleted = 1;
-    h->heap[index].expiration = 0;
-    bubble_up(h, index + 1);
-    return 0;
-}
-
-void timeout_heap_set_free_callback(TimeoutHeap *h, void* user_data, void (*callback)(void* user_data, void* data)) {
-    if (!h) return;
-    h->user_data = user_data;
-    h->free_callback = callback;
-}
-
-size_t timeout_heap_get_size(TimeoutHeap *h) {
-    if (!h) return 0;
-    return h->size;
-}
diff --git a/lib/timeout_heap.h b/lib/timeout_heap.h
deleted file mode 100644
index 8e093f2f..00000000
--- a/lib/timeout_heap.h
+++ /dev/null
@@ -1,97 +0,0 @@
-// timeout_heap.h
-
-#ifndef TIMEOUT_HEAP_H
-#define TIMEOUT_HEAP_H
-
-#include <stdint.h>  // For uint64_t
-#include <stddef.h>  // For size_t
-
-typedef uint64_t TimeoutTime;  // e.g., milliseconds since epoch or from now
-
-typedef struct {
-    TimeoutTime expiration;  // Sort key (smaller = earlier)
-    void *data;              // User data (e.g., callback or ID)
-    size_t *index_ptr;       // Pointer to node's heap_index (NULL = no tracking)
-    int deleted;             // 0 = active, 1 = deleted
-} TimeoutEntry;
-
-typedef struct TimeoutHeap TimeoutHeap;
-
-struct TimeoutHeap {
-    TimeoutEntry *heap;      // Dynamic array
-    size_t size;             // Current number of elements
-    size_t capacity;         // Allocated size
-    size_t freed_count;      // Number of freed timer nodes
-    void* user_data;         // User data for free callback
-    void (*free_callback)(void* user_data, void* data); // Callback to free data
-};
-
-/**
- * Create a new timeout heap with initial capacity.
- * @param initial_capacity Starting capacity (will grow as needed).
- * @return Pointer to the heap, or NULL on failure.
- */
-TimeoutHeap *timeout_heap_create(size_t initial_capacity);
-
-/**
- * Destroy the timeout heap and free resources.
- * @param h The heap to destroy.
- */
-void timeout_heap_destroy(TimeoutHeap *h);
-
-/**
- * Set a callback function to free data when deleted nodes are removed.
- * @param h The heap.
- * @param user_data User data passed to callback.
- * @param callback Callback function (if NULL, data is freed with free()).
- */
-void timeout_heap_set_free_callback(TimeoutHeap *h, void* user_data, void (*callback)(void* user_data, void* data));
-
-/**
- * Insert a new timeout into the heap.
- * @param h The heap.
- * @param expiration The expiration time.
- * @param data User data associated with the timeout.
- * @return 0 on success, -1 on allocation failure.
- */
-int timeout_heap_push(TimeoutHeap *h, TimeoutTime expiration, void *data, size_t *index_ptr);
-
-/**
- * Peek at the earliest non-deleted timeout without removing it.
- * @param h The heap.
- * @param out Where to store the entry.
- * @return 0 on success, -1 if empty.
- */
-int timeout_heap_peek(TimeoutHeap *h, TimeoutEntry *out);
-
-/**
- * Pop the earliest non-deleted timeout from the heap.
- * @param h The heap.
- * @param out Where to store the entry.
- * @return 0 on success, -1 if empty.
- */
-int timeout_heap_pop(TimeoutHeap *h, TimeoutEntry *out);
-
-/**
- * Cancel a timeout by matching expiration and data.
- * Scans the heap linearly, so O(n) time.
- * Assumes combinations are unique; cancels the first match.
- * @param h The heap.
- * @param expiration The expiration time to match.
- * @param data The data to match.
- * @return 0 if found and canceled, -1 if not found.
- */
-int timeout_heap_cancel(TimeoutHeap *h, TimeoutTime expiration, void *data);
-
-int timeout_heap_cancel_at(TimeoutHeap *h, size_t index, void *data);
-
-/**
- * Get the number of freed timer nodes.
- * @param h The heap.
- * @return Count of freed timer nodes.
- */
-size_t timeout_heap_get_freed_count(TimeoutHeap *h);
-
-size_t timeout_heap_get_size(TimeoutHeap *h);
-
-#endif // TIMEOUT_HEAP_H
diff --git a/lib/twheel.c b/lib/twheel.c
new file mode 100644
index 00000000..ccbdbc1f
--- /dev/null
+++ b/lib/twheel.c
@@ -0,0 +1,223 @@
+// twheel.c — Tickless hierarchical timing wheel (adapted from timeout.c)
+// Original: Copyright (c) 2013-2014 William Ahern, MIT license.
+
+#include <limits.h>
+#include <stddef.h>
+#include <string.h>
+#include <errno.h>
+#include <sys/queue.h>
+
+#include "twheel.h"
+#include "mem.h"
+#include "debug_config.h"
+
+#define WHEEL_BIT 6
+#define WHEEL_NUM 4
+
+#define WHEEL_LEN  (1U << WHEEL_BIT)
+#define WHEEL_MAX  (WHEEL_LEN - 1)
+#define WHEEL_MASK (WHEEL_LEN - 1)
+
+#include "twheel_bitops.c"
+
+#define ctz(n) ctz64(n)
+#define clz(n) clz64(n)
+#define fls(n) ((int)(64 - clz64(n)))
+
+typedef uint64_t wheel_t;
+#define WHEEL_C(n) UINT64_C(n)
+
+#define countof(a) (sizeof(a) / sizeof *(a))
+
+#ifndef TAILQ_CONCAT
+#define TAILQ_CONCAT(head1, head2, field) do {                          \
+    if (!TAILQ_EMPTY(head2)) {                                          \
+        *(head1)->tqh_last = (head2)->tqh_first;                        \
+        (head2)->tqh_first->field.tqe_prev = (head1)->tqh_last;         \
+        (head1)->tqh_last = (head2)->tqh_last;                          \
+        TAILQ_INIT((head2));                                            \
+    }                                                                   \
+} while (0)
+#endif
+
+#ifndef TAILQ_FOREACH_SAFE
+#define TAILQ_FOREACH_SAFE(var, head, field, tvar)                      \
+    for ((var) = TAILQ_FIRST(head);                                     \
+        (var) && ((tvar) = TAILQ_NEXT(var, field), 1);                  \
+        (var) = (tvar))
+#endif
+
+#ifndef MAX
+#define MAX(a,b) (((a)>(b))?(a):(b))
+#endif
+#ifndef MIN
+#define MIN(a,b) (((a)<(b))?(a):(b))
+#endif
+
+static inline wheel_t rotl(const wheel_t v, int c) {
+    if (!(c &= (sizeof v * CHAR_BIT - 1))) return v;
+    return (v << c) | (v >> (sizeof v * CHAR_BIT - c));
+}
+
+static inline wheel_t rotr(const wheel_t v, int c) {
+    if (!(c &= (sizeof v * CHAR_BIT - 1))) return v;
+    return (v >> c) | (v << (sizeof v * CHAR_BIT - c));
+}
+
+static struct twheels *twheels_init(struct twheels *T, twheel_t hz) {
+    for (unsigned i = 0; i < WHEEL_NUM; i++) {
+        for (unsigned j = 0; j < WHEEL_LEN; j++) {
+            TAILQ_INIT(&T->wheel[i][j]);
+        }
+    }
+    TAILQ_INIT(&T->expired);
+    for (unsigned i = 0; i < WHEEL_NUM; i++) T->pending[i] = 0;
+    T->curtime = 0;
+    T->hertz = hz ? hz : TWHEEL_mHZ;
+    return T;
+}
+
+struct twheels *twheels_open(twheel_t hz) {
+    struct twheels *T = u_malloc(sizeof *T);
+    if (!T) { DEBUG_ERROR(DEBUG_CATEGORY_TIMERS, "twheels_open: malloc failed"); return NULL; }
+    return twheels_init(T, hz);
+}
+
+void twheels_close(struct twheels *T) {
+    if (!T) return;
+    struct twheel_list reset;
+    TAILQ_INIT(&reset);
+    for (unsigned i = 0; i < WHEEL_NUM; i++)
+        for (unsigned j = 0; j < WHEEL_LEN; j++)
+            TAILQ_CONCAT(&reset, &T->wheel[i][j], tqe);
+    TAILQ_CONCAT(&reset, &T->expired, tqe);
+    struct twheel *to;
+    TAILQ_FOREACH(to, &reset, tqe) to->pending = NULL;
+    u_free(T);
+}
+
+twheel_t twheels_hz(struct twheels *T) { return T->hertz; }
+
+void twheels_del(struct twheels *T, struct twheel *to) {
+    if (to->pending) {
+        TAILQ_REMOVE(to->pending, to, tqe);
+        if (to->pending != &T->expired && TAILQ_EMPTY(to->pending)) {
+            ptrdiff_t index = to->pending - &T->wheel[0][0];
+            int w = index / WHEEL_LEN, slot = index % WHEEL_LEN;
+            T->pending[w] &= ~(WHEEL_C(1) << slot);
+        }
+        to->pending = NULL;
+    }
+}
+
+static inline int timeout_wheel(twheel_t timeout) {
+    return (fls(MIN(timeout, TWHEEL_MAX)) - 1) / WHEEL_BIT;
+}
+
+static inline int timeout_slot(int wheel, twheel_t expires) {
+    return WHEEL_MASK & ((expires >> (wheel * WHEEL_BIT)) - !!wheel);
+}
+
+static void twheels_sched(struct twheels *T, struct twheel *to, twheel_t expires) {
+    twheels_del(T, to);
+    to->expires = expires;
+    if (expires > T->curtime) {
+        twheel_t rem = expires - T->curtime;
+        int wheel = timeout_wheel(rem);
+        int slot = timeout_slot(wheel, to->expires);
+        to->pending = &T->wheel[wheel][slot];
+        TAILQ_INSERT_TAIL(to->pending, to, tqe);
+        T->pending[wheel] |= WHEEL_C(1) << slot;
+    } else {
+        to->pending = &T->expired;
+        TAILQ_INSERT_TAIL(to->pending, to, tqe);
+    }
+}
+
+void twheels_add(struct twheels *T, struct twheel *to, twheel_t timeout) {
+    if (to->flags & TWHEEL_INT) to->interval = MAX(1, timeout);
+    if (to->flags & TWHEEL_ABS) twheels_sched(T, to, timeout);
+    else twheels_sched(T, to, T->curtime + timeout);
+}
+
+void twheels_update(struct twheels *T, twheel_t curtime) {
+    twheel_t elapsed = curtime - T->curtime;
+    struct twheel_list todo;
+    TAILQ_INIT(&todo);
+
+    for (int wheel = 0; wheel < WHEEL_NUM; wheel++) {
+        wheel_t pending;
+        if ((elapsed >> (wheel * WHEEL_BIT)) > WHEEL_MAX) {
+            pending = (wheel_t)~WHEEL_C(0);
+        } else {
+            wheel_t _elapsed = WHEEL_MASK & (elapsed >> (wheel * WHEEL_BIT));
+            int oslot = WHEEL_MASK & (T->curtime >> (wheel * WHEEL_BIT));
+            pending = rotl(((UINT64_C(1) << _elapsed) - 1), oslot);
+            int nslot = WHEEL_MASK & (curtime >> (wheel * WHEEL_BIT));
+            pending |= rotr(rotl(((WHEEL_C(1) << _elapsed) - 1), nslot), _elapsed);
+            pending |= WHEEL_C(1) << nslot;
+        }
+        while (pending & T->pending[wheel]) {
+            int slot = ctz(pending & T->pending[wheel]);
+            TAILQ_CONCAT(&todo, &T->wheel[wheel][slot], tqe);
+            T->pending[wheel] &= ~(UINT64_C(1) << slot);
+        }
+        if (!(0x1 & pending)) break;
+        elapsed = MAX(elapsed, (WHEEL_LEN << (wheel * WHEEL_BIT)));
+    }
+    T->curtime = curtime;
+
+    struct twheel *to;
+    while (!TAILQ_EMPTY(&todo)) {
+        to = TAILQ_FIRST(&todo);
+        TAILQ_REMOVE(&todo, to, tqe);
+        to->pending = NULL;
+        twheels_sched(T, to, to->expires);
+    }
+}
+
+bool twheels_pending(struct twheels *T) {
+    wheel_t pending = 0;
+    for (int wheel = 0; wheel < WHEEL_NUM; wheel++) pending |= T->pending[wheel];
+    return !!pending;
+}
+
+bool twheels_expired(struct twheels *T) { return !TAILQ_EMPTY(&T->expired); }
+
+static twheel_t twheels_int(struct twheels *T) {
+    twheel_t timeout = ~TWHEEL_C(0), _timeout, relmask = 0;
+    for (int wheel = 0; wheel < WHEEL_NUM; wheel++) {
+        if (T->pending[wheel]) {
+            int slot = WHEEL_MASK & (T->curtime >> (wheel * WHEEL_BIT));
+            _timeout = (ctz(rotr(T->pending[wheel], slot)) + !!wheel) << (wheel * WHEEL_BIT);
+            _timeout -= relmask & T->curtime;
+            timeout = MIN(_timeout, timeout);
+        }
+        relmask <<= WHEEL_BIT;
+        relmask |= WHEEL_MASK;
+    }
+    return timeout;
+}
+
+twheel_t twheels_timeout(struct twheels *T) {
+    if (!TAILQ_EMPTY(&T->expired)) return 0;
+    return twheels_int(T);
+}
+
+struct twheel *twheels_get(struct twheels *T) {
+    if (!TAILQ_EMPTY(&T->expired)) {
+        struct twheel *to = TAILQ_FIRST(&T->expired);
+        TAILQ_REMOVE(&T->expired, to, tqe);
+        to->pending = NULL;
+        return to;
+    }
+    return NULL;
+}
+
+struct twheel *twheel_init(struct twheel *to, int flags) {
+    memset(to, 0, sizeof *to);
+    to->flags = flags;
+    return to;
+}
+
+bool twheel_pending(struct twheel *to) { return to->pending != NULL; }
diff --git a/lib/twheel.h b/lib/twheel.h
new file mode 100644
index 00000000..33553829
--- /dev/null
+++ b/lib/twheel.h
@@ -0,0 +1,57 @@
+// twheel.h — Tickless hierarchical timing wheel (adapted from timeout.h)
+// Original: Copyright (c) 2013-2014 William Ahern, MIT license.
+
+#ifndef TWHEEL_H
+#define TWHEEL_H
+
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <sys/queue.h>
+
+#define TWHEEL_VERSION 0x20160226
+
+typedef uint64_t twheel_t;
+#define TWHEEL_C(n)  UINT64_C(n)
+#define TWHEEL_mHZ   TWHEEL_C(1000)
+#define TWHEEL_MAX   ((TWHEEL_C(1) << 24) - 1)
+
+enum twheel_flags {
+    TWHEEL_INT = 0x01,
+    TWHEEL_ABS = 0x02,
+};
+
+#define TWHEEL_INITIALIZER(flags) { (flags) }
+
+struct twheel {
+    int flags;
+    twheel_t expires;
+    struct twheel_list *pending;
+    TAILQ_ENTRY(twheel) tqe;
+    twheel_t interval;
+};
+
+TAILQ_HEAD(twheel_list, twheel);
+
+struct twheels {
+    struct twheel_list wheel[4][64], expired;
+    uint64_t pending[4];
+    twheel_t curtime;
+    twheel_t hertz;
+};
+
+struct twheel *twheel_init(struct twheel *, int flags);
+bool twheel_pending(struct twheel *);
+
+struct twheels *twheels_open(twheel_t hz);
+void twheels_close(struct twheels *);
+twheel_t twheels_hz(struct twheels *);
+void twheels_update(struct twheels *, twheel_t curtime);
+twheel_t twheels_timeout(struct twheels *);
+void twheels_add(struct twheels *, struct twheel *, twheel_t timeout);
+void twheels_del(struct twheels *, struct twheel *);
+struct twheel *twheels_get(struct twheels *);
+bool twheels_pending(struct twheels *);
+bool twheels_expired(struct twheels *);
+
+#endif
diff --git a/lib/twheel_bitops.c b/lib/twheel_bitops.c
new file mode 100644
index 00000000..58a977db
--- /dev/null
+++ b/lib/twheel_bitops.c
@@ -0,0 +1,35 @@
+// twheel_bitops.c — ctz/clz for timing wheel (included by twheel.c)
+
+#include <stdint.h>
+
+#if defined(__GNUC__) && !defined(TWHEEL_DISABLE_GNUC_BITOPS)
+#define ctz64(n) __builtin_ctzll(n)
+#define clz64(n) __builtin_clzll(n)
+#if LONG_BITS == 32
+#define ctz32(n) __builtin_ctzl(n)
+#define clz32(n) __builtin_clzl(n)
+#else
+#define ctz32(n) __builtin_ctz(n)
+#define clz32(n) __builtin_clz(n)
+#endif
+#elif defined(_MSC_VER) && !defined(TWHEEL_DISABLE_MSVC_BITOPS)
+#include <intrin.h>
+static __inline int ctz32(unsigned long val) { DWORD z=0; _BitScanForward(&z,val); return z; }
+static __inline int clz32(unsigned long val) { DWORD z=0; _BitScanReverse(&z,val); return z; }
+#ifdef _WIN64
+static __inline int ctz64(uint64_t val) { DWORD z=0; _BitScanForward64(&z,val); return z; }
+static __inline int clz64(uint64_t val) { DWORD z=0; _BitScanReverse64(&z,val); return z; }
+#else
+static __inline int ctz64(uint64_t val) { uint32_t lo=(uint32_t)val,hi=(uint32_t)(val>>32); return lo?ctz32(lo):32+ctz32(hi); }
+static __inline int clz64(uint64_t val) { uint32_t lo=(uint32_t)val,hi=(uint32_t)(val>>32); return hi?clz32(hi):32+clz32(lo); }
+#endif
+#else
+#define process_(one, cz_bits, bits) if (x < ( one << (cz_bits - bits))) { rv += bits; x <<= bits; }
+static inline int clz64(uint64_t x) { int rv=0; process_(UINT64_C(1),64,32); process_(UINT64_C(1),64,16); process_(UINT64_C(1),64,8); process_(UINT64_C(1),64,4); process_(UINT64_C(1),64,2); process_(UINT64_C(1),64,1); return rv; }
+static inline int clz32(uint32_t x) { int rv=0; process_(UINT32_C(1),32,16); process_(UINT32_C(1),32,8); process_(UINT32_C(1),32,4); process_(UINT32_C(1),32,2); process_(UINT32_C(1),32,1); return rv; }
+#undef process_
+#define process_(one, bits) if ((x & ((one << (bits))-1)) == 0) { rv += bits; x >>= bits; }
+static inline int ctz64(uint64_t x) { int rv=0; process_(UINT64_C(1),32); process_(UINT64_C(1),16); process_(UINT64_C(1),8); process_(UINT64_C(1),4); process_(UINT64_C(1),2); process_(UINT64_C(1),1); return rv; }
+static inline int ctz32(uint32_t x) { int rv=0; process_(UINT32_C(1),16); process_(UINT32_C(1),8); process_(UINT32_C(1),4); process_(UINT32_C(1),2); process_(UINT32_C(1),1); return rv; }
+#undef process_
+#endif
diff --git a/lib/u_async.c b/lib/u_async.c
index 67448299..4cad19d2 100644
--- a/lib/u_async.c
+++ b/lib/u_async.c
@@ -4,7 +4,8 @@
 #include "platform_compat.h"
 #include "debug_config.h"
 #include "mem.h"
-#include "memory_pool.h"
+#include "memory_pool.h"
+#include "twheel.h"
 #include <stdio.h>
 #include <string.h>
 #include <stdlib.h>
@@ -32,13 +33,12 @@
 
 // Timeout node with safe cancellation
 struct timeout_node {
+    struct twheel to;        // MUST be first — embedded timing wheel entry
     char name[16];
     void* arg;
     timeout_callback_t callback;
-    uint64_t expiration_ms; // absolute expiration time in milliseconds
     struct UASYNC* ua;      // Pointer back to uasync instance for counter updates
     struct timeout_node* next;  // For immediate queue (FIFO)
-    size_t heap_index;       // Position in timeout_heap (SIZE_MAX if not in heap)
 };
 
 // Socket node with array-based storage
@@ -290,16 +290,7 @@ static struct socket_node* socket_array_get_by_sock(struct socket_array* sa, soc
     return &sa->sockets[index];
 }
 
-// Callback to u_free timeout node and update counters
-static void timeout_node_free_callback(void* user_data, void* data) {
-    struct UASYNC* ua = (struct UASYNC*)user_data;
-    struct timeout_node* node = (struct timeout_node*)data;
-    (void)node; // Not used directly, but keep for consistency
-    ua->timer_free_count++;
-    memory_pool_free(ua->timeout_pool, data);
-}
-
-// Helper to get current time
+// Simplified timeout handling without reference counting
 static void get_current_time(struct timeval* tv) {
 #ifdef _WIN32
     // Для Windows используем GetTickCount или другие механизмы
@@ -435,8 +426,8 @@ static uint64_t timeval_to_ms(const struct timeval* tv) {
 
 
 
-// Simplified timeout handling without reference counting
-
+// Simplified timeout handling without reference counting
+
 // Process expired timeouts with safe cancellation
 static void process_timeouts(struct UASYNC* ua) {
     if (!ua) return;
@@ -460,63 +451,40 @@ static void process_timeouts(struct UASYNC* ua) {
         memory_pool_free(ua->timeout_pool, node);
     }
     
-    if (!ua->timeout_heap) return;
+    if (!ua->twheel) return;
     
     struct timeval now_tv;
     get_current_time(&now_tv);
     uint64_t now_ms = timeval_to_ms(&now_tv);
     
-    while (1) {
-        TimeoutEntry entry;
-        if (timeout_heap_peek(ua->timeout_heap, &entry) != 0) break;
-        if (entry.expiration > now_ms) break;
-        
-        // Pop the expired timeout
-        timeout_heap_pop(ua->timeout_heap, &entry);
-        struct timeout_node* node = (struct timeout_node*)entry.data;
+    // Update timing wheel to current time — moves expired to expired queue
+    twheels_update(ua->twheel, now_ms);
+    
+    // Drain all expired timeouts
+    struct twheel *to;
+    while ((to = twheels_get(ua->twheel))) {
+        struct timeout_node* node = (struct timeout_node*)to;
         
         if (node && node->callback) {
             DEBUG_DEBUG(DEBUG_CATEGORY_UASYNC, "timer→%s expired", node->name[0] ? node->name : "");
             node->callback(node->arg);
         }
         
-        // Always u_free the node after processing
         if (node && node->ua) {
             node->ua->timer_free_count++;
         }
         memory_pool_free(ua->timeout_pool, node);
-        continue;  // Process next expired timeout
     }
 }
 
-// Compute time to next timeout
-static void get_next_timeout(struct UASYNC* ua, struct timeval* tv) {
-    if (!ua || !ua->timeout_heap) {
-        tv->tv_sec = 0;
-        tv->tv_usec = 0;
-        return;
-    }
-    
-    TimeoutEntry entry;
-    if (timeout_heap_peek(ua->timeout_heap, &entry) != 0) {
-        tv->tv_sec = 0;
-        tv->tv_usec = 0;
-        return;
-    }
-    
-    struct timeval now_tv;
-    get_current_time(&now_tv);
-    uint64_t now_ms = timeval_to_ms(&now_tv);
-    
-    if (entry.expiration <= now_ms) {
-        tv->tv_sec = 0;
-        tv->tv_usec = 0;
-        return;
-    }
-    
-    uint64_t delta_ms = entry.expiration - now_ms;
-    tv->tv_sec = delta_ms / 1000;
-    tv->tv_usec = (delta_ms % 1000) * 1000;
+// Compute time to next timeout in milliseconds
+// Returns: 0 = timer already expired/no timers, ~0 = no pending timers, >0 = ms to wait
+static uint64_t get_next_timeout_ms(struct UASYNC* ua) {
+    if (!ua || !ua->twheel) return 0;
+    twheel_t t = twheels_timeout(ua->twheel);
+    if (t == 0)        return 0;                     // expired timer exists
+    if (t == ~TWHEEL_C(0)) return ~TWHEEL_C(0);       // no pending timers
+    return (uint64_t)t;
 }
 
 
@@ -524,9 +492,7 @@ static void get_next_timeout(struct UASYNC* ua, struct timeval* tv) {
 // Instance version
 void* uasync_set_timeout(struct UASYNC* ua, int timeout_tb, void* arg, timeout_callback_t callback, const char* name) {
     if (!ua || timeout_tb < 0 || !callback) return NULL;
-    if (!ua->timeout_heap) return NULL;
-    
-//    DEBUG_DEBUG(DEBUG_CATEGORY_TIMERS, "uasync_set_timeout: timeout=%d.%d ms, arg=%p, callback=%p", timeout_tb/10, timeout_tb%10, arg, callback);
+    if (!ua->twheel) return NULL;
     
     struct timeout_node* node = memory_pool_alloc(ua->timeout_pool);
     if (!node) {
@@ -544,24 +510,19 @@ void* uasync_set_timeout(struct UASYNC* ua, int timeout_tb, void* arg, timeout_c
     node->arg = arg;
     node->callback = callback;
     node->ua = ua;
-    node->heap_index = SIZE_MAX;
     
-    // Calculate expiration time in milliseconds
+    // Calculate expiration time in milliseconds (absolute monotonic)
     struct timeval now;
     get_current_time(&now);
     timeval_add_tb(&now, timeout_tb);
-    node->expiration_ms = timeval_to_ms(&now);
+    uint64_t expiration_ms = timeval_to_ms(&now);
+    
+    // Initialize wheel entry and add to timing wheel
+    twheel_init(&node->to, TWHEEL_ABS);
+    twheels_add(ua->twheel, &node->to, expiration_ms);
     
-    // Add to heap
-    if (timeout_heap_push(ua->timeout_heap, node->expiration_ms, node, &node->heap_index) != 0) {
-        DEBUG_ERROR(DEBUG_CATEGORY_TIMERS, "uasync_set_timeout: failed to push to heap");
-        memory_pool_free(ua->timeout_pool, node);
-        ua->timer_free_count++;  // Balance the alloc counter
-        return NULL;
-    }
-    
     return node;
-}
+}
 
 // Immediate execution in next mainloop (FIFO order)
 void* uasync_call_soon(struct UASYNC* ua, void* user_arg, timeout_callback_t callback) {
@@ -579,9 +540,8 @@ void* uasync_call_soon(struct UASYNC* ua, void* user_arg, timeout_callback_t cal
     node->arg = user_arg;
     node->callback = callback;
     node->ua = ua;
-    node->expiration_ms = 0;
     node->next = NULL;
-    node->heap_index = SIZE_MAX;
+    memset(&node->to, 0, sizeof(node->to));
     
     // FIFO: добавляем в конец очереди
     if (ua->immediate_queue_tail) {
@@ -609,30 +569,26 @@ err_t uasync_call_soon_cancel(struct UASYNC* ua, void* t_id) {
 
 
 
-// Instance version
+// Instance version
 err_t uasync_cancel_timeout(struct UASYNC* ua, void* t_id) {
-    if (!ua || !t_id || !ua->timeout_heap) {
-        DEBUG_ERROR(DEBUG_CATEGORY_TIMERS, "uasync_cancel_timeout: invalid parameters ua=%p, t_id=%p, heap=%p", 
-                    ua, t_id, ua ? ua->timeout_heap : NULL);
+    if (!ua || !t_id || !ua->twheel) {
+        DEBUG_ERROR(DEBUG_CATEGORY_TIMERS, "uasync_cancel_timeout: invalid parameters ua=%p, t_id=%p, twheel=%p", 
+                    ua, t_id, ua ? ua->twheel : NULL);
         return ERR_FAIL;
     }
 
     struct timeout_node* node = (struct timeout_node*)t_id;
 
-    if (node->heap_index == SIZE_MAX || node->heap_index >= ua->timeout_heap->size ||
-        ua->timeout_heap->heap[node->heap_index].data != node) {
-        DEBUG_DEBUG(DEBUG_CATEGORY_TIMERS, "uasync_cancel_timeout: not found in heap: ua=%p, t_id=%p, node=%p, expires=%llu ms", 
-                    ua, t_id, node, (unsigned long long)node->expiration_ms);
+    if (!twheel_pending(&node->to)) {
+        DEBUG_DEBUG(DEBUG_CATEGORY_TIMERS, "uasync_cancel_timeout: not pending: ua=%p, t_id=%p", ua, t_id);
         return ERR_FAIL;
     }
     
-    if (timeout_heap_cancel_at(ua->timeout_heap, node->heap_index, node) == 0) {
-        node->heap_index = SIZE_MAX;
-        node->callback = NULL;
-        return ERR_OK;
-    }
-
-    return ERR_FAIL;
+    twheels_del(ua->twheel, &node->to);
+    node->callback = NULL;
+    ua->timer_free_count++;
+    memory_pool_free(ua->timeout_pool, node);
+    return ERR_OK;
 }
 
 
@@ -970,65 +926,39 @@ static void process_epoll_events(struct UASYNC* ua, struct epoll_event* events,
 }
 #endif
 
-// Instance version
-void uasync_poll(struct UASYNC* ua, int timeout_tb) {
-    if (!ua) return;
-    if (!ua->sockets || !ua->timeout_heap) return;
-
-    DEBUG_DEBUG(DEBUG_CATEGORY_UASYNC, "poll(%d sockets, %zu timers, timeout=%d.%dms)",
-                ua->sockets->count, ua->timeout_heap->size, timeout_tb >= 0 ? timeout_tb / 10000 : -1,
-                timeout_tb >= 0 ? (timeout_tb % 10000) / 10 : 0);
-    
-    // Handle negative or zero timeout
-    if (timeout_tb < 0) timeout_tb = -1;  // Infinite wait
-    else if (timeout_tb == 0) timeout_tb = 0;  // No wait
-    
-    // Get next timeout
-    struct timeval next_timeout;
-    get_next_timeout(ua, &next_timeout);
-    
-    // Convert requested timeout to timeval
-    struct timeval req_timeout = {0};
-    if (timeout_tb >= 0) {
-        req_timeout.tv_sec = timeout_tb / 10000;
-        req_timeout.tv_usec = (timeout_tb % 10000) * 100;
-    }
-    
-    struct timeval poll_timeout;
+// Instance version
+void uasync_poll(struct UASYNC* ua, int timeout_tb) {
+    if (!ua) return;
+    if (!ua->sockets || !ua->twheel) return;
+
+    DEBUG_DEBUG(DEBUG_CATEGORY_UASYNC, "poll(%d sockets, timeout=%d.%dms)",
+                ua->sockets->count, timeout_tb >= 0 ? timeout_tb / 10000 : -1,
+                timeout_tb >= 0 ? (timeout_tb % 10000) / 10 : 0);
+    
+    uint64_t next_ms = get_next_timeout_ms(ua);  // 0=expired, ~0=no timers, >0=ms to wait
+    
+    int timeout_ms;
     if (timeout_tb < 0) {
-        poll_timeout = next_timeout;
+        // Infinite wait or until next timer
+        if (next_ms == 0)         timeout_ms = 0;    // Expired timer, don't wait
+        else if (next_ms != ~TWHEEL_C(0)) timeout_ms = (int)next_ms; // Wait for next timer
+        else                     timeout_ms = -1;   // No timers, infinite wait
     } else {
-        if (next_timeout.tv_sec < req_timeout.tv_sec ||
-            (next_timeout.tv_sec == req_timeout.tv_sec && next_timeout.tv_usec < req_timeout.tv_usec)) {
-            poll_timeout = next_timeout;
-        } else {
-            poll_timeout = req_timeout;
-        }
+        int req_ms = timeout_tb / 10;  // timebase to ms
+        if (next_ms == 0)        timeout_ms = 0;    // Expired timer, don't wait
+        else if (next_ms != ~TWHEEL_C(0)) timeout_ms = (int)(next_ms < (uint64_t)req_ms ? next_ms : (uint64_t)req_ms);
+        else                     timeout_ms = req_ms;
     }
-    if (poll_timeout.tv_sec == 0 && poll_timeout.tv_usec == 0 && timeout_tb > 0) poll_timeout = req_timeout;
-
-    
-    int timeout_ms;
-    if (timeout_tb < 0 && (next_timeout.tv_sec > 0 || next_timeout.tv_usec > 0)) {
-        timeout_ms = (poll_timeout.tv_sec * 1000) + (poll_timeout.tv_usec / 1000);
-    } else if (timeout_tb < 0) {
-        timeout_ms = -1;  // Infinite
-    } else {
-        timeout_ms = (poll_timeout.tv_sec * 1000) + (poll_timeout.tv_usec / 1000);
-    }
-    
-    // Count active sockets
-    int socket_count = ua->sockets->count;
-    if (socket_count == 0 && timeout_ms == -1) {
-        // No sockets and infinite wait - but we have timers? Wait for timer
-        if (ua->timeout_heap->size > 0) {
-            timeout_ms = (poll_timeout.tv_sec * 1000) + (poll_timeout.tv_usec / 1000);
-        } else {
-            // Nothing to do - return immediately
-            return;
-        }
-    }
-    
+    
+    int socket_count = ua->sockets->count;
+    if (socket_count == 0 && timeout_ms == -1) {
+        // No sockets and infinite wait — but we might have timers
+        if (twheels_pending(ua->twheel) || twheels_expired(ua->twheel))
+            timeout_ms = 0;  // Let process_timeouts handle them
+        else
+            return;          // Nothing to do
+    }
+    
 #if HAS_EPOLL
     // Use epoll on Linux if available
     if (ua->use_epoll && ua->epoll_fd >= 0) {
@@ -1330,8 +1260,8 @@ struct UASYNC* uasync_create(void) {
         return NULL;
     }
 
-    ua->timeout_heap = timeout_heap_create(16);
-    if (!ua->timeout_heap) {
+    ua->twheel = twheels_open(TWHEEL_mHZ);
+    if (!ua->twheel) {
         socket_array_destroy(ua->sockets);
         if (ua->wakeup_initialized) {
 #ifdef _WIN32
@@ -1349,7 +1279,7 @@ struct UASYNC* uasync_create(void) {
     // Initialize timeout pool
     ua->timeout_pool = memory_pool_init(sizeof(struct timeout_node));
     if (!ua->timeout_pool) {
-        timeout_heap_destroy(ua->timeout_heap);
+        twheels_close(ua->twheel);
         socket_array_destroy(ua->sockets);
         if (ua->wakeup_initialized) {
 #ifdef _WIN32
@@ -1364,10 +1294,7 @@ struct UASYNC* uasync_create(void) {
         return NULL;
     }
 
-    // Set callback to u_free timeout nodes and update counters
-    timeout_heap_set_free_callback(ua->timeout_heap, ua, timeout_node_free_callback);
-
-    DEBUG_DEBUG(DEBUG_CATEGORY_ETCP, "Creating TH1...");
+    DEBUG_DEBUG(DEBUG_CATEGORY_ETCP, "Creating TH1...");
     // Initialize epoll on Linux
     ua->epoll_fd = -1;
     ua->use_epoll = 0;
@@ -1479,18 +1406,11 @@ void uasync_print_resources(struct UASYNC* ua, const char* prefix) {
            (ssize_t)(ua->socket_alloc_count - ua->socket_free_count));
     
     // Показать активные таймеры
-    if (ua->timeout_heap) {
-        size_t active_timers = 0;
-        // Безопасное чтение без извлечения - просто итерируем по массиву
-        for (size_t i = 0; i < ua->timeout_heap->size; i++) {
-            if (!ua->timeout_heap->heap[i].deleted) {
-                active_timers++;
-                struct timeout_node* node = (struct timeout_node*)ua->timeout_heap->heap[i].data;
-                DEBUG_INFO(DEBUG_CATEGORY_UASYNC, "   Timer: node=%p, expires=%llu ms",
-                       node, (unsigned long long)ua->timeout_heap->heap[i].expiration);
-            }
-        }
-        DEBUG_INFO(DEBUG_CATEGORY_UASYNC, "   Active timers in heap: %zu", active_timers);
+    if (ua->twheel) {
+        bool has_pending = twheels_pending(ua->twheel);
+        bool has_expired = twheels_expired(ua->twheel);
+        DEBUG_INFO(DEBUG_CATEGORY_UASYNC, "   Timing wheel: pending=%d expired=%d curtime=%llu",
+               has_pending, has_expired, (unsigned long long)ua->twheel->curtime);
     }
     
     // Показать активные сокеты
@@ -1549,21 +1469,30 @@ void uasync_destroy(struct UASYNC* ua, int close_fds) {
     }
     ua->immediate_queue_tail = NULL;
     
-    // Очистить heap
-    if (ua->timeout_heap) {
-        while (1) {
-            TimeoutEntry entry;
-            if (timeout_heap_pop(ua->timeout_heap, &entry) != 0) break;
-            struct timeout_node* node = (struct timeout_node*)entry.data;
-
-            // Free all timer nodes (avoid double-u_free bug)
-            if (node) {
-                ua->timer_free_count++;
-                memory_pool_free(ua->timeout_pool, node);
+    // Очистить timing wheel
+    if (ua->twheel) {
+        for (int w = 0; w < 4; w++) {
+            for (int s = 0; s < 64; s++) {
+                struct twheel *to;
+                while (!TAILQ_EMPTY(&ua->twheel->wheel[w][s])) {
+                    to = TAILQ_FIRST(&ua->twheel->wheel[w][s]);
+                    TAILQ_REMOVE(&ua->twheel->wheel[w][s], to, tqe);
+                    struct timeout_node* node = (struct timeout_node*)to;
+                    ua->timer_free_count++;
+                    memory_pool_free(ua->timeout_pool, node);
+                }
             }
         }
-        timeout_heap_destroy(ua->timeout_heap);
-        ua->timeout_heap = NULL;
+        struct twheel *to;
+        while (!TAILQ_EMPTY(&ua->twheel->expired)) {
+            to = TAILQ_FIRST(&ua->twheel->expired);
+            TAILQ_REMOVE(&ua->twheel->expired, to, tqe);
+            struct timeout_node* node = (struct timeout_node*)to;
+            ua->timer_free_count++;
+            memory_pool_free(ua->timeout_pool, node);
+        }
+        twheels_close(ua->twheel);
+        ua->twheel = NULL;
     }
 
     // Destroy timeout pool
diff --git a/lib/u_async.h b/lib/u_async.h
index 187e12b7..a65dc712 100644
--- a/lib/u_async.h
+++ b/lib/u_async.h
@@ -8,7 +8,6 @@
 #include "platform_compat.h"
 #include <stddef.h>
 #include <signal.h>
-#include "timeout_heap.h"
 #include "socket_compat.h"
 
 typedef void (*timeout_callback_t)(void* user_arg);// передаёт user_arg из uasync_set_timeout
@@ -30,12 +29,13 @@ typedef void (*uasync_post_callback_t)(void* user_arg);
 
 #include "memory_pool.h"
 
-struct timeout_node;  // Forward declaration
+struct timeout_node;
+struct twheels;
 
-struct posted_task {
-        uasync_post_callback_t callback;
-        void* arg;
-        struct posted_task* next;
+struct posted_task {
+        uasync_post_callback_t callback;
+        void* arg;
+        struct posted_task* next;
     };
 
 // Uasync instance structure
@@ -43,7 +43,7 @@ struct UASYNC {
     struct memory_pool* timeout_pool;  // Pool for timeout_node allocation
     struct timeout_node* immediate_queue_head;  // FIFO queue for immediate execution
     struct timeout_node* immediate_queue_tail;
-    TimeoutHeap* timeout_heap;  // Heap for timeout management
+    struct twheels* twheel;  // Timing wheel for timeout management
     struct socket_array* sockets; // Array-based socket management
     // Debug counters for memory allocation tracking
     size_t timer_alloc_count;
diff --git a/src/control_server.c b/src/control_server.c
index d45ddea2..cf5b95ce 100644
--- a/src/control_server.c
+++ b/src/control_server.c
@@ -14,7 +14,6 @@
 #include "pkt_normalizer.h"
 #include "../tools/etcpmon/etcpmon_protocol.h"
 #include "../lib/u_async.h"
-#include "../lib/timeout_heap.h"
 #include "../lib/memory_pool.h"
 #include "../lib/debug_config.h"
 #include "../lib/mem.h"
@@ -1028,11 +1027,7 @@ static void send_metrics(struct control_server* server, struct control_client* c
     }
 
     /* System resources */
-    if (instance->ua && instance->ua->timeout_heap) {
-        rsp->etcp.active_timeouts = (uint32_t)timeout_heap_get_size(instance->ua->timeout_heap);
-    } else {
-        rsp->etcp.active_timeouts = 0;
-    }
+    rsp->etcp.active_timeouts = 0;
 
     rsp->etcp.busy_memory_blocks = (uint32_t)(u_get_allocated_count() - memory_pool_get_total_free_blocks());
     
diff --git a/src/etcp.c b/src/etcp.c
index 3911ffa2..a7b8cb08 100644
--- a/src/etcp.c
+++ b/src/etcp.c
@@ -752,6 +752,7 @@ static void ack_timeout_check(struct ETCP_CONN* etcp) {
             // shedule timer
             int64_t next_timeout=timeout - elapsed;
             if (next_timeout<0) next_timeout=0;
+            if (next_timeout>timeout) next_timeout=timeout;
             DEBUG_TRACE(DEBUG_CATEGORY_ETCP, "[%s] retransmission timer set for %llu units", etcp->log_name, next_timeout);
             etcp->retrans_timer = uasync_set_timeout(etcp->instance->ua, next_timeout+10, etcp, ack_timeout_cb, "etcp_retrans");
             return;
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 5e72c999..388f2ecf 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -42,7 +42,6 @@ check_PROGRAMS = \
 	test_bbr_integration \
 	test_intensive_memory_pool \
 	test_tcp_io \
-	bench_timeout_heap \
 	bench_uasync_timeouts
 
 # Долгие тесты: запускаются только вручную, не включаются в make check
diff --git a/tests/bench_uasync_timeouts.c b/tests/bench_uasync_timeouts.c
index ec2b231d..78c8c325 100644
--- a/tests/bench_uasync_timeouts.c
+++ b/tests/bench_uasync_timeouts.c
@@ -71,7 +71,7 @@ static void benchmark_without_sockets(void) {
     printf("Set %d zero timeouts:\n", NUM_TIMEOUTS);
     printf("  Total time: %.3f ms\n", set_time);
     printf("  Average per timeout: %.3f us\n", (set_time * 1000.0) / NUM_TIMEOUTS);
-    printf("  Heap size: %zu\n\n", ua->timeout_heap->size);
+    printf("  Heap size: N/A (timing wheel)\n\n");
 
     // Run mainloop 100 times
     clock_gettime(CLOCK_MONOTONIC, &start);
@@ -84,7 +84,7 @@ static void benchmark_without_sockets(void) {
     printf("Run mainloop (uasync_poll) %d times:\n", NUM_TIMEOUTS);
     printf("  Total time: %.3f ms\n", mainloop_time);
     printf("  Average per iteration: %.3f us\n", (mainloop_time * 1000.0) / NUM_TIMEOUTS);
-    printf("  Heap size after: %zu\n\n", ua->timeout_heap->size);
+    printf("  Heap size after: N/A (timing wheel)\n\n");
 
     printf("--- Results WITHOUT sockets ---\n");
     printf("Set timeouts: %.3f ms (%.3f us/op)\n", set_time, (set_time * 1000.0) / NUM_TIMEOUTS);
@@ -163,7 +163,7 @@ static void benchmark_with_sockets(void) {
     printf("Set %d zero timeouts (with %d sockets open):\n", NUM_TIMEOUTS, NUM_SOCKETS);
     printf("  Total time: %.3f ms\n", set_time);
     printf("  Average per timeout: %.3f us\n", (set_time * 1000.0) / NUM_TIMEOUTS);
-    printf("  Heap size: %zu\n\n", ua->timeout_heap->size);
+    printf("  Heap size: N/A (timing wheel)\n\n");
 
     // Run mainloop 100 times WITH sockets
     clock_gettime(CLOCK_MONOTONIC, &start);
@@ -176,7 +176,7 @@ static void benchmark_with_sockets(void) {
     printf("Run mainloop (uasync_poll) %d times (with sockets):\n", NUM_TIMEOUTS);
     printf("  Total time: %.3f ms\n", mainloop_time);
     printf("  Average per iteration: %.3f us\n", (mainloop_time * 1000.0) / NUM_TIMEOUTS);
-    printf("  Heap size after: %zu\n\n", ua->timeout_heap->size);
+    printf("  Heap size after: N/A (timing wheel)\n\n");
 
     printf("--- Results WITH %d sockets ---\n", NUM_SOCKETS);
     printf("Set timeouts: %.3f ms (%.3f us/op)\n", set_time, (set_time * 1000.0) / NUM_TIMEOUTS);
diff --git a/tests/test_u_async_comprehensive.c b/tests/test_u_async_comprehensive.c
index b88d25b2..41c98351 100644
--- a/tests/test_u_async_comprehensive.c
+++ b/tests/test_u_async_comprehensive.c
@@ -10,7 +10,6 @@
 #include "../lib/platform_compat.h"
 
 #include "u_async.h"
-#include "timeout_heap.h"
 #include "debug_config.h"
 #include "../lib/mem.h"