Merge pull request #684 from taosdata/feature/newtimer

new timer implementation

src/inc/ttimer.h

@@ -21,40 +21,41 @@ extern "C" {
 #endif
 
 typedef void *tmr_h;
+typedef void (*TAOS_TMR_CALLBACK)(void *, void *);
 
 extern uint32_t tmrDebugFlag;
-extern int taosTmrThreads;
+extern int      taosTmrThreads;
 
 #define tmrError(...)                                 \
-  if (tmrDebugFlag & DEBUG_ERROR) {                   \
+  do { if (tmrDebugFlag & DEBUG_ERROR) {              \
     tprintf("ERROR TMR ", tmrDebugFlag, __VA_ARGS__); \
-  }
+  } } while(0)
+
 #define tmrWarn(...)                                  \
-  if (tmrDebugFlag & DEBUG_WARN) {                    \
+  do { if (tmrDebugFlag & DEBUG_WARN) {               \
     tprintf("WARN  TMR ", tmrDebugFlag, __VA_ARGS__); \
-  }
+  } } while(0)
+
 #define tmrTrace(...)                           \
-  if (tmrDebugFlag & DEBUG_TRACE) {             \
+  do { if (tmrDebugFlag & DEBUG_TRACE) {        \
     tprintf("TMR ", tmrDebugFlag, __VA_ARGS__); \
-  }
+  } } while(0)
 
-#define MAX_NUM_OF_TMRCTL 512
+#define MAX_NUM_OF_TMRCTL 32
 #define MSECONDS_PER_TICK 5
 
-void *taosTmrInit(int maxTmr, int resoultion, int longest, char *label);
+void *taosTmrInit(int maxTmr, int resoultion, int longest, const char *label);
 
-tmr_h taosTmrStart(void (*fp)(void *, void *), int mseconds, void *param1, void *handle);
+tmr_h taosTmrStart(TAOS_TMR_CALLBACK fp, int mseconds, void *param, void *handle);
 
-void taosTmrStop(tmr_h tmrId);
+bool taosTmrStop(tmr_h tmrId);
 
-void taosTmrStopA(tmr_h *timerId);
+bool taosTmrStopA(tmr_h *timerId);
 
-void taosTmrReset(void (*fp)(void *, void *), int mseconds, void *param1, void *handle, tmr_h *pTmrId);
+bool taosTmrReset(TAOS_TMR_CALLBACK fp, int mseconds, void *param, void *handle, tmr_h *pTmrId);
 
 void taosTmrCleanUp(void *handle);
 
-void taosTmrList(void *handle);
-
 #ifdef __cplusplus
 }
 #endif

src/os/darwin/inc/os.h

@@ -55,10 +55,44 @@
 #define taosWriteSocket(fd, buf, len) write(fd, buf, len)
 #define taosReadSocket(fd, buf, len) read(fd, buf, len)
 
+#define atomic_load_8(ptr) __atomic_load_n((ptr), __ATOMIC_SEQ_CST)
+#define atomic_load_16(ptr) __atomic_load_n((ptr), __ATOMIC_SEQ_CST)
+#define atomic_load_32(ptr) __atomic_load_n((ptr), __ATOMIC_SEQ_CST)
+#define atomic_load_64(ptr) __atomic_load_n((ptr), __ATOMIC_SEQ_CST)
+#define atomic_load_ptr(ptr) __atomic_load_n((ptr), __ATOMIC_SEQ_CST)
+
+#define atomic_store_8(ptr, val) __atomic_store_n((ptr), (val), __ATOMIC_SEQ_CST)
+#define atomic_store_16(ptr, val) __atomic_store_n((ptr), (val), __ATOMIC_SEQ_CST)
+#define atomic_store_32(ptr, val) __atomic_store_n((ptr), (val), __ATOMIC_SEQ_CST)
+#define atomic_store_64(ptr, val) __atomic_store_n((ptr), (val), __ATOMIC_SEQ_CST)
+#define atomic_store_ptr(ptr, val) __atomic_store_n((ptr), (val), __ATOMIC_SEQ_CST)
+
+#define atomic_exchange_8(ptr, val) __atomic_exchange_n((ptr), (val), __ATOMIC_SEQ_CST)
+#define atomic_exchange_16(ptr, val) __atomic_exchange_n((ptr), (val), __ATOMIC_SEQ_CST)
+#define atomic_exchange_32(ptr, val) __atomic_exchange_n((ptr), (val), __ATOMIC_SEQ_CST)
+#define atomic_exchange_64(ptr, val) __atomic_exchange_n((ptr), (val), __ATOMIC_SEQ_CST)
+#define atomic_exchange_ptr(ptr, val) __atomic_exchange_n((ptr), (val), __ATOMIC_SEQ_CST)
+
+// TODO: update prefix of below macros to 'atomic' as '__' is reserved by compiler
+// and GCC suggest new code to use '__atomic' builtins to replace '__sync' builtins.
 #define __sync_val_compare_and_swap_64 __sync_val_compare_and_swap
 #define __sync_val_compare_and_swap_32 __sync_val_compare_and_swap
+#define __sync_val_compare_and_swap_16 __sync_val_compare_and_swap
+#define __sync_val_compare_and_swap_8 __sync_val_compare_and_swap
+#define __sync_val_compare_and_swap_ptr __sync_val_compare_and_swap
+
 #define __sync_add_and_fetch_64 __sync_add_and_fetch
 #define __sync_add_and_fetch_32 __sync_add_and_fetch
+#define __sync_add_and_fetch_16 __sync_add_and_fetch
+#define __sync_add_and_fetch_8 __sync_add_and_fetch
+#define __sync_add_and_fetch_ptr __sync_add_and_fetch
+
+#define __sync_sub_and_fetch_64 __sync_sub_and_fetch
+#define __sync_sub_and_fetch_32 __sync_sub_and_fetch
+#define __sync_sub_and_fetch_16 __sync_sub_and_fetch
+#define __sync_sub_and_fetch_8 __sync_sub_and_fetch
+#define __sync_sub_and_fetch_ptr __sync_sub_and_fetch
+
 int32_t __sync_val_load_32(int32_t *ptr);
 void __sync_val_restore_32(int32_t *ptr, int32_t newval);
 

src/os/linux/inc/os.h

@@ -71,14 +71,43 @@ extern "C" {
 #define taosWriteSocket(fd, buf, len) write(fd, buf, len)
 #define taosReadSocket(fd, buf, len) read(fd, buf, len)
 
+#define atomic_load_8(ptr) __atomic_load_n((ptr), __ATOMIC_SEQ_CST)
+#define atomic_load_16(ptr) __atomic_load_n((ptr), __ATOMIC_SEQ_CST)
+#define atomic_load_32(ptr) __atomic_load_n((ptr), __ATOMIC_SEQ_CST)
+#define atomic_load_64(ptr) __atomic_load_n((ptr), __ATOMIC_SEQ_CST)
+#define atomic_load_ptr(ptr) __atomic_load_n((ptr), __ATOMIC_SEQ_CST)
+
+#define atomic_store_8(ptr, val) __atomic_store_n((ptr), (val), __ATOMIC_SEQ_CST)
+#define atomic_store_16(ptr, val) __atomic_store_n((ptr), (val), __ATOMIC_SEQ_CST)
+#define atomic_store_32(ptr, val) __atomic_store_n((ptr), (val), __ATOMIC_SEQ_CST)
+#define atomic_store_64(ptr, val) __atomic_store_n((ptr), (val), __ATOMIC_SEQ_CST)
+#define atomic_store_ptr(ptr, val) __atomic_store_n((ptr), (val), __ATOMIC_SEQ_CST)
+
+#define atomic_exchange_8(ptr, val) __atomic_exchange_n((ptr), (val), __ATOMIC_SEQ_CST)
+#define atomic_exchange_16(ptr, val) __atomic_exchange_n((ptr), (val), __ATOMIC_SEQ_CST)
+#define atomic_exchange_32(ptr, val) __atomic_exchange_n((ptr), (val), __ATOMIC_SEQ_CST)
+#define atomic_exchange_64(ptr, val) __atomic_exchange_n((ptr), (val), __ATOMIC_SEQ_CST)
+#define atomic_exchange_ptr(ptr, val) __atomic_exchange_n((ptr), (val), __ATOMIC_SEQ_CST)
+
+// TODO: update prefix of below macros to 'atomic' as '__' is reserved by compiler
+// and GCC suggest new code to use '__atomic' builtins to replace '__sync' builtins.
 #define __sync_val_compare_and_swap_64 __sync_val_compare_and_swap
 #define __sync_val_compare_and_swap_32 __sync_val_compare_and_swap
+#define __sync_val_compare_and_swap_16 __sync_val_compare_and_swap
+#define __sync_val_compare_and_swap_8 __sync_val_compare_and_swap
+#define __sync_val_compare_and_swap_ptr __sync_val_compare_and_swap
 
 #define __sync_add_and_fetch_64 __sync_add_and_fetch
 #define __sync_add_and_fetch_32 __sync_add_and_fetch
+#define __sync_add_and_fetch_16 __sync_add_and_fetch
+#define __sync_add_and_fetch_8 __sync_add_and_fetch
+#define __sync_add_and_fetch_ptr __sync_add_and_fetch
 
 #define __sync_sub_and_fetch_64 __sync_sub_and_fetch
 #define __sync_sub_and_fetch_32 __sync_sub_and_fetch
+#define __sync_sub_and_fetch_16 __sync_sub_and_fetch
+#define __sync_sub_and_fetch_8 __sync_sub_and_fetch
+#define __sync_sub_and_fetch_ptr __sync_sub_and_fetch
 
 int32_t __sync_val_load_32(int32_t *ptr);
 void __sync_val_restore_32(int32_t *ptr, int32_t newval);

src/os/windows/inc/os.h

@@ -29,6 +29,7 @@
 #include <math.h>
 #include <string.h>
 #include <assert.h>
+#include <intrin.h>
 
 #ifdef __cplusplus
 extern "C" {
@@ -78,12 +79,75 @@ extern "C" {
 #define taosWriteSocket(fd, buf, len) send(fd, buf, len, 0)
 #define taosReadSocket(fd, buf, len) recv(fd, buf, len, 0)
 
-int32_t __sync_val_compare_and_swap_32(int32_t *ptr, int32_t oldval, int32_t newval);
-int32_t __sync_add_and_fetch_32(int32_t *ptr, int32_t val);
-int32_t __sync_sub_and_fetch_32(int32_t *ptr, int32_t val);
-int64_t __sync_val_compare_and_swap_64(int64_t *ptr, int64_t oldval, int64_t newval);
-int64_t __sync_add_and_fetch_64(int64_t *ptr, int64_t val);
-int64_t __sync_sub_and_fetch_64(int64_t *ptr, int64_t val);
+#if defined(_M_ARM) || defined(_M_ARM64)
+
+#define atomic_load_8(ptr) __iso_volatile_load8((const volatile __int8*)(ptr))
+#define atomic_load_16(ptr) __iso_volatile_load16((const volatile __int16*)(ptr))
+#define atomic_load_32(ptr) __iso_volatile_load32((const volatile __int32*)(ptr))
+#define atomic_load_64(ptr) __iso_volatile_load64((const volatile __int64*)(ptr))
+
+#define atomic_store_8(ptr, val) __iso_volatile_store8((volatile __int8*)(ptr), (__int8)(val))
+#define atomic_store_16(ptr, val) __iso_volatile_store16((volatile __int16*)(ptr), (__int16)(val))
+#define atomic_store_32(ptr, val) __iso_volatile_store32((volatile __int32*)(ptr), (__int32)(val))
+#define atomic_store_64(ptr, val) __iso_volatile_store64((volatile __int64*)(ptr), (__int64)(val))
+
+#ifdef _M_ARM64
+#define atomic_load_ptr atomic_load_64
+#define atomic_store_ptr atomic_store_64
+#else
+#define atomic_load_ptr atomic_load_32
+#define atomic_store_ptr atomic_store_32
+#endif
+
+#else
+
+#define atomic_load_8(ptr) (*(char volatile*)(ptr))
+#define atomic_load_16(ptr) (*(short volatile*)(ptr))
+#define atomic_load_32(ptr) (*(long volatile*)(ptr))
+#define atomic_load_64(ptr) (*(__int64 volatile*)(ptr))
+#define atomic_load_ptr(ptr) (*(void* volatile*)(ptr))
+
+#define atomic_store_8(ptr, val) ((*(char volatile*)(ptr)) = (char)(val))
+#define atomic_store_16(ptr, val) ((*(short volatile*)(ptr)) = (short)(val))
+#define atomic_store_32(ptr, val) ((*(long volatile*)(ptr)) = (long)(val))
+#define atomic_store_64(ptr, val) ((*(__int64 volatile*)(ptr)) = (__int64)(val))
+#define atomic_store_ptr(ptr, val) ((*(void* volatile*)(ptr)) = (void*)(val))
+
+#endif
+
+#define atomic_exchange_8(ptr, val) _InterlockedExchange8((char volatile*)(ptr), (char)(val))
+#define atomic_exchange_16(ptr, val) _InterlockedExchange16((short volatile*)(ptr), (short)(val))
+#define atomic_exchange_32(ptr, val) _InterlockedExchange((long volatile*)(ptr), (long)(val))
+#define atomic_exchange_64(ptr, val) _InterlockedExchange64((__int64 volatile*)(ptr), (__int64)(val))
+#define atomic_exchange_ptr(ptr, val) _InterlockedExchangePointer((void* volatile*)(ptr), (void*)(val))
+
+#define __sync_val_compare_and_swap_8(ptr, oldval, newval) _InterlockedCompareExchange8((char volatile*)(ptr), (char)(newval), (char)(oldval))
+#define __sync_val_compare_and_swap_16(ptr, oldval, newval) _InterlockedCompareExchange16((short volatile*)(ptr), (short)(newval), (short)(oldval))
+#define __sync_val_compare_and_swap_32(ptr, oldval, newval) _InterlockedCompareExchange((long volatile*)(ptr), (long)(newval), (long)(oldval))
+#define __sync_val_compare_and_swap_64(ptr, oldval, newval) _InterlockedCompareExchange64((__int64 volatile*)(ptr), (__int64)(newval), (__int64)(oldval))
+#define __sync_val_compare_and_swap_ptr(ptr, oldval, newval) _InterlockedCompareExchangePointer((void* volatile*)(ptr), (void*)(newval), (void*)(oldval))
+
+char    interlocked_add_8(char volatile *ptr, char val);
+short   interlocked_add_16(short volatile *ptr, short val);
+long    interlocked_add_32(long volatile *ptr, long val);
+__int64 interlocked_add_64(__int64 volatile *ptr, __int64 val);
+
+#define __sync_add_and_fetch_8(ptr, val) interlocked_add_8((char volatile*)(ptr), (char)(val))
+#define __sync_add_and_fetch_16(ptr, val) interlocked_add_16((short volatile*)(ptr), (short)(val))
+#define __sync_add_and_fetch_32(ptr, val) interlocked_add_32((long volatile*)(ptr), (long)(val))
+#define __sync_add_and_fetch_64(ptr, val) interlocked_add_64((__int64 volatile*)(ptr), (__int64)(val))
+#ifdef _WIN64
+  #define __sync_add_and_fetch_ptr __sync_add_and_fetch_64
+#else
+  #define __sync_add_and_fetch_ptr __sync_add_and_fetch_32
+#endif
+
+#define __sync_sub_and_fetch_8(ptr, val) __sync_add_and_fetch_8((ptr), -(val))
+#define __sync_sub_and_fetch_16(ptr, val) __sync_add_and_fetch_16((ptr), -(val))
+#define __sync_sub_and_fetch_32(ptr, val) __sync_add_and_fetch_32((ptr), -(val))
+#define __sync_sub_and_fetch_64(ptr, val) __sync_add_and_fetch_64((ptr), -(val))
+#define __sync_sub_and_fetch_ptr(ptr, val) __sync_add_and_fetch_ptr((ptr), -(val))
+
 int32_t __sync_val_load_32(int32_t *ptr);
 void __sync_val_restore_32(int32_t *ptr, int32_t newval);
 

src/os/windows/src/twindows.c

@@ -43,8 +43,11 @@ void taosResetPthread(pthread_t *thread) {
 }
 
 int64_t taosGetPthreadId() {
-  pthread_t id = pthread_self();
-  return (int64_t)id.p;
+#ifdef PTW32_VERSION
+  return pthread_getw32threadid_np(pthread_self());
+#else
+  return (int64_t)pthread_self();
+#endif
 }
 
 int taosSetSockOpt(int socketfd, int level, int optname, void *optval, int optlen) {
@@ -63,28 +66,21 @@ int taosSetSockOpt(int socketfd, int level, int optname, void *optval, int optle
   return setsockopt(socketfd, level, optname, optval, optlen);
 }
 
-int32_t __sync_val_compare_and_swap_32(int32_t *ptr, int32_t oldval, int32_t newval) {
-  return InterlockedCompareExchange(ptr, newval, oldval);
-}
-
-int32_t __sync_add_and_fetch_32(int32_t *ptr, int32_t val) {
-  return InterlockedAdd(ptr, val);
-}
 
-int32_t __sync_sub_and_fetch_32(int32_t *ptr, int32_t val) {
-  return InterlockedAdd(ptr, -val);
+char interlocked_add_8(char volatile* ptr, char val) {
+  return _InterlockedExchangeAdd8(ptr, val) + val;
 }
 
-int64_t __sync_val_compare_and_swap_64(int64_t *ptr, int64_t oldval, int64_t newval) {
-  return InterlockedCompareExchange64(ptr, newval, oldval);
+short interlocked_add_16(short volatile* ptr, short val) {
+  return _InterlockedExchangeAdd16(ptr, val) + val;
 }
 
-int64_t __sync_add_and_fetch_64(int64_t *ptr, int64_t val) {
-  return InterlockedAdd64(ptr, val);
+long interlocked_add_32(long volatile* ptr, long val) {
+  return _InterlockedExchangeAdd(ptr, val) + val;
 }
 
-int64_t __sync_sub_and_fetch_64(int64_t *ptr, int64_t val) {
-  return InterlockedAdd64(ptr, -val);
+__int64 interlocked_add_64(__int64 volatile* ptr, __int64 val) {
+  return _InterlockedExchangeAdd64(ptr, val) + val;
 }
 
 int32_t __sync_val_load_32(int32_t *ptr) {

src/util/src/ttimer.c

@@ -16,555 +16,539 @@
 #include <assert.h>
 #include <errno.h>
 #include <pthread.h>
-#include <semaphore.h>
-#include <signal.h>
+#include <sched.h>
 #include <stdio.h>
 #include <stdlib.h>
-#include <string.h>
-
 #include "os.h"
-#include "tidpool.h"
 #include "tlog.h"
 #include "tsched.h"
+#include "ttime.h"
 #include "ttimer.h"
 #include "tutil.h"
 
-// special mempool without mutex
-#define mpool_h void *
-
-typedef struct {
-  int   numOfFree;  /* number of free slots */
-  int   first;      /* the first free slot  */
-  int   numOfBlock; /* the number of blocks */
-  int   blockSize;  /* block size in bytes  */
-  int * freeList;   /* the index list       */
-  char *pool;       /* the actual mem block */
-} pool_t;
-
-mpool_h tmrMemPoolInit(int maxNum, int blockSize);
-char *tmrMemPoolMalloc(mpool_h handle);
-void tmrMemPoolFree(mpool_h handle, char *p);
-void tmrMemPoolCleanUp(mpool_h handle);
-
-typedef struct _tmr_obj {
-  void *param1;
-  void (*fp)(void *, void *);
-  tmr_h               timerId;
-  short               cycle;
-  struct _tmr_obj *   prev;
-  struct _tmr_obj *   next;
-  int                 index;
-  struct _tmr_ctrl_t *pCtrl;
-} tmr_obj_t;
-
-typedef struct {
-  tmr_obj_t *head;
-  int        count;
-} tmr_list_t;
-
-typedef struct _tmr_ctrl_t {
-  void *          signature;
-  pthread_mutex_t mutex;            /* mutex to protect critical resource */
-  int             resolution;       /* resolution in mseconds */
-  int             numOfPeriods;     /* total number of periods */
-  int64_t         periodsFromStart; /* count number of periods since start */
-  pthread_t       thread;           /* timer thread ID */
-  tmr_list_t *    tmrList;
-  mpool_h         poolHandle;
-  char            label[12];
-  int             maxNumOfTmrs;
-  int             numOfTmrs;
-  int             ticks;
-  int             maxTicks;
-  int             tmrCtrlId;
-} tmr_ctrl_t;
 
-uint32_t  tmrDebugFlag = DEBUG_ERROR | DEBUG_WARN | DEBUG_FILE;
-void taosTmrProcessList(tmr_ctrl_t *);
-
-tmr_ctrl_t tmrCtrl[MAX_NUM_OF_TMRCTL];
-int        numOfTmrCtrl = 0;
-void *     tmrIdPool = NULL;
-void *     tmrQhandle;
-int        taosTmrThreads = 1;
-
-void taosTimerLoopFunc(int signo) {
-  tmr_ctrl_t *pCtrl;
-  int         count = 0;
-
-  for (int i = 1; i < MAX_NUM_OF_TMRCTL; ++i) {
-    pCtrl = tmrCtrl + i;
-    if (pCtrl->signature) {
-      count++;
-      pCtrl->ticks++;
-      if (pCtrl->ticks >= pCtrl->maxTicks) {
-        taosTmrProcessList(pCtrl);
-        pCtrl->ticks = 0;
-      }
-      if (count >= numOfTmrCtrl) break;
-    }
-  }
-}
+#define TIMER_STATE_WAITING 0
+#define TIMER_STATE_EXPIRED 1
+#define TIMER_STATE_STOPPED 2
+#define TIMER_STATE_CANCELED 3
 
-void taosTmrModuleInit(void) {
-  tmrIdPool = taosInitIdPool(MAX_NUM_OF_TMRCTL);
-  memset(tmrCtrl, 0, sizeof(tmrCtrl));
+typedef union _tmr_ctrl_t {
+  char label[16];
+  struct {
+    // pad to ensure 'next' is the end of this union
+    char               padding[16 - sizeof(union _tmr_ctrl_t*)];
+    union _tmr_ctrl_t* next;
+  };
+} tmr_ctrl_t;
 
-  taosInitTimer(taosTimerLoopFunc, MSECONDS_PER_TICK);
+typedef struct tmr_obj_t {
+  uintptr_t         id;
+  tmr_ctrl_t*       ctrl;
+  struct tmr_obj_t* mnext;
+  struct tmr_obj_t* prev;
+  struct tmr_obj_t* next;
+  uint16_t          slot;
+  uint8_t           wheel;
+  uint8_t           state;
+  uint8_t           refCount;
+  uint8_t           reserved1;
+  uint16_t          reserved2;
+  union {
+    int64_t expireAt;
+    int64_t executedBy;
+  };
+  TAOS_TMR_CALLBACK fp;
+  void*             param;
+} tmr_obj_t;
 
-  tmrQhandle = taosInitScheduler(10000, taosTmrThreads, "tmr");
-  tmrTrace("timer module is initialized, thread:%d", taosTmrThreads);
+typedef struct timer_list_t {
+  int64_t    lockedBy;
+  tmr_obj_t* timers;
+} timer_list_t;
+
+typedef struct timer_map_t {
+  uint32_t      size;
+  uint32_t      count;
+  timer_list_t* slots;
+} timer_map_t;
+
+typedef struct time_wheel_t {
+  pthread_mutex_t mutex;
+  int64_t         nextScanAt;
+  uint32_t        resolution;
+  uint16_t        size;
+  uint16_t        index;
+  tmr_obj_t**     slots;
+} time_wheel_t;
+
+uint32_t tmrDebugFlag = DEBUG_ERROR | DEBUG_WARN | DEBUG_FILE;
+
+static pthread_once_t  tmrModuleInit = PTHREAD_ONCE_INIT;
+static pthread_mutex_t tmrCtrlMutex;
+static tmr_ctrl_t      tmrCtrls[MAX_NUM_OF_TMRCTL];
+static tmr_ctrl_t*     unusedTmrCtrl = NULL;
+void*                  tmrQhandle;
+int                    taosTmrThreads = 1;
+
+static uintptr_t nextTimerId = 0;
+
+static time_wheel_t wheels[] = {
+    {.resolution = MSECONDS_PER_TICK, .size = 4096},
+    {.resolution = 1000, .size = 1024},
+    {.resolution = 60000, .size = 1024},
+};
+static timer_map_t timerMap;
+
+static uintptr_t getNextTimerId() {
+  uintptr_t id;
+  do {
+    id = __sync_add_and_fetch_ptr(&nextTimerId, 1);
+  } while (id == 0);
+  return id;
 }
 
-void *taosTmrInit(int maxNumOfTmrs, int resolution, int longest, char *label) {
-  static pthread_once_t tmrInit = PTHREAD_ONCE_INIT;
-  tmr_ctrl_t *          pCtrl;
+static void timerAddRef(tmr_obj_t* timer) { __sync_add_and_fetch_8(&timer->refCount, 1); }
 
-  pthread_once(&tmrInit, taosTmrModuleInit);
-
-  int tmrCtrlId = taosAllocateId(tmrIdPool);
-
-  if (tmrCtrlId < 0) {
-    tmrError("%s bug!!! too many timers!!!", label);
-    return NULL;
-  }
-
-  pCtrl = tmrCtrl + tmrCtrlId;
-  tfree(pCtrl->tmrList);
-  tmrMemPoolCleanUp(pCtrl->poolHandle);
-
-  memset(pCtrl, 0, sizeof(tmr_ctrl_t));
-
-  pCtrl->tmrCtrlId = tmrCtrlId;
-  strcpy(pCtrl->label, label);
-  pCtrl->maxNumOfTmrs = maxNumOfTmrs;
-
-  if ((pCtrl->poolHandle = tmrMemPoolInit(maxNumOfTmrs + 10, sizeof(tmr_obj_t))) == NULL) {
-    tmrError("%s failed to allocate mem pool", label);
-    tmrMemPoolCleanUp(pCtrl->poolHandle);
-    return NULL;
+static void timerDecRef(tmr_obj_t* timer) {
+  if (__sync_sub_and_fetch_8(&timer->refCount, 1) == 0) {
+    free(timer);
   }
+}
 
-  if (resolution < MSECONDS_PER_TICK) resolution = MSECONDS_PER_TICK;
-  pCtrl->resolution = resolution;
-  pCtrl->maxTicks = resolution / MSECONDS_PER_TICK;
-  pCtrl->ticks = rand() / pCtrl->maxTicks;
-  pCtrl->numOfPeriods = longest / resolution;
-  if (pCtrl->numOfPeriods < 10) pCtrl->numOfPeriods = 10;
-
-  pCtrl->tmrList = (tmr_list_t *)malloc(sizeof(tmr_list_t) * pCtrl->numOfPeriods);
-  if (pCtrl->tmrList == NULL) {
-    tmrError("%s failed to allocate(size:%d) mem for tmrList", label, sizeof(tmr_list_t) * pCtrl->numOfPeriods);
-    tmrMemPoolCleanUp(pCtrl->poolHandle);
-    taosTmrCleanUp(pCtrl);
-    return NULL;
-  }
-  
-  for (int i = 0; i < pCtrl->numOfPeriods; i++) {
-    pCtrl->tmrList[i].head = NULL;
-    pCtrl->tmrList[i].count = 0;
+static void lockTimerList(timer_list_t* list) {
+  int64_t tid = taosGetPthreadId();
+  int       i = 0;
+  while (__sync_val_compare_and_swap_64(&(list->lockedBy), 0, tid) != 0) {
+    if (++i % 1000 == 0) {
+      sched_yield();
+    }
   }
+}
 
-  if (pthread_mutex_init(&pCtrl->mutex, NULL) < 0) {
-    tmrError("%s failed to create the mutex, reason:%s", label, strerror(errno));
-    taosTmrCleanUp(pCtrl);
-    return NULL;
+static void unlockTimerList(timer_list_t* list) {
+  int64_t tid = taosGetPthreadId();
+  if (__sync_val_compare_and_swap_64(&(list->lockedBy), tid, 0) != tid) {
+    assert(false);
+    tmrError("trying to unlock a timer list not locked by current thread.");
   }
-
-  pCtrl->signature = pCtrl;
-  numOfTmrCtrl++;
-  tmrTrace("%s timer ctrl is initialized, index:%d", label, tmrCtrlId);
-  return pCtrl;
 }
 
-void taosTmrProcessList(tmr_ctrl_t *pCtrl) {
-  unsigned int index;
-  tmr_list_t * pList;
-  tmr_obj_t *  pObj, *header;
+static void addTimer(tmr_obj_t* timer) {
+  timerAddRef(timer);
+  timer->wheel = tListLen(wheels);
 
-  pthread_mutex_lock(&pCtrl->mutex);
-  index = pCtrl->periodsFromStart % pCtrl->numOfPeriods;
-  pList = &pCtrl->tmrList[index];
+  uint32_t      idx = (uint32_t)(timer->id % timerMap.size);
+  timer_list_t* list = timerMap.slots + idx;
 
-  while (1) {
-    header = pList->head;
-    if (header == NULL) break;
+  lockTimerList(list);
+  timer->mnext = list->timers;
+  list->timers = timer;
+  unlockTimerList(list);
+}
 
-    if (header->cycle > 0) {
-      pObj = header;
-      while (pObj) {
-        pObj->cycle--;
-        pObj = pObj->next;
+static tmr_obj_t* findTimer(uintptr_t id) {
+  tmr_obj_t* timer = NULL;
+  if (id > 0) {
+    uint32_t      idx = (uint32_t)(id % timerMap.size);
+    timer_list_t* list = timerMap.slots + idx;
+    lockTimerList(list);
+    for (timer = list->timers; timer != NULL; timer = timer->mnext) {
+      if (timer->id == id) {
+        timerAddRef(timer);
+        break;
       }
-      break;
     }
-
-    pCtrl->numOfTmrs--;
-    tmrTrace("%s %p, timer expired, fp:%p, tmr_h:%p, index:%d, total:%d", pCtrl->label, header->param1, header->fp,
-             header, index, pCtrl->numOfTmrs);
-
-    pList->head = header->next;
-    if (header->next) header->next->prev = NULL;
-    pList->count--;
-    header->timerId = NULL;
-
-    SSchedMsg schedMsg;
-    schedMsg.fp = NULL;
-    schedMsg.tfp = header->fp;
-    schedMsg.ahandle = header->param1;
-    schedMsg.thandle = header;
-    taosScheduleTask(tmrQhandle, &schedMsg);
-
-    tmrMemPoolFree(pCtrl->poolHandle, (char *)header);
+    unlockTimerList(list);
   }
-
-  pCtrl->periodsFromStart++;
-  pthread_mutex_unlock(&pCtrl->mutex);
-}
-
-void taosTmrCleanUp(void *handle) {
-  tmr_ctrl_t *pCtrl = (tmr_ctrl_t *)handle;
-  if (pCtrl == NULL || pCtrl->signature != pCtrl) return;
-
-  pCtrl->signature = NULL;
-  taosFreeId(tmrIdPool, pCtrl->tmrCtrlId);
-  numOfTmrCtrl--;
-  tmrTrace("%s is cleaned up, numOfTmrs:%d", pCtrl->label, numOfTmrCtrl);
+  return timer;
 }
 
-tmr_h taosTmrStart(void (*fp)(void *, void *), int mseconds, void *param1, void *handle) {
-  tmr_obj_t * pObj, *cNode, *pNode;
-  tmr_list_t *pList;
-  int         index, period;
-  tmr_ctrl_t *pCtrl = (tmr_ctrl_t *)handle;
-
-  if (handle == NULL) return NULL;
-
-  period = mseconds / pCtrl->resolution;
-  if (pthread_mutex_lock(&pCtrl->mutex) != 0)
-    tmrError("%s mutex lock failed, reason:%s", pCtrl->label, strerror(errno));
-
-  pObj = (tmr_obj_t *)tmrMemPoolMalloc(pCtrl->poolHandle);
-  if (pObj == NULL) {
-    tmrError("%s reach max number of timers:%d", pCtrl->label, pCtrl->maxNumOfTmrs);
-    pthread_mutex_unlock(&pCtrl->mutex);
-    return NULL;
+static void removeTimer(uintptr_t id) {
+  tmr_obj_t*    prev = NULL;
+  uint32_t      idx = (uint32_t)(id % timerMap.size);
+  timer_list_t* list = timerMap.slots + idx;
+  lockTimerList(list);
+  for (tmr_obj_t* p = list->timers; p != NULL; p = p->mnext) {
+    if (p->id == id) {
+      if (prev == NULL) {
+        list->timers = p->mnext;
+      } else {
+        prev->mnext = p->mnext;
+      }
+      timerDecRef(p);
+      break;
+    }
+    prev = p;
   }
+  unlockTimerList(list);
+}
 
-  pObj->cycle = period / pCtrl->numOfPeriods;
-  pObj->param1 = param1;
-  pObj->fp = fp;
-  pObj->timerId = pObj;
-  pObj->pCtrl = pCtrl;
-
-  index = (period + pCtrl->periodsFromStart) % pCtrl->numOfPeriods;
-  int cindex = (pCtrl->periodsFromStart) % pCtrl->numOfPeriods;
-  pList = &(pCtrl->tmrList[index]);
-
-  pObj->index = index;
-  cNode = pList->head;
-  pNode = NULL;
-
-  while (cNode != NULL) {
-    if (cNode->cycle < pObj->cycle) {
-      pNode = cNode;
-      cNode = cNode->next;
-    } else {
+static void addToWheel(tmr_obj_t* timer, uint32_t delay) {
+  timerAddRef(timer);
+  // select a wheel for the timer, we are not an accurate timer,
+  // but the inaccuracy should not be too large.
+  timer->wheel = tListLen(wheels) - 1;
+  for (uint8_t i = 0; i < tListLen(wheels); i++) {
+    time_wheel_t* wheel = wheels + i;
+    if (delay < wheel->resolution * wheel->size) {
+      timer->wheel = i;
       break;
     }
   }
 
-  pObj->next = cNode;
-  pObj->prev = pNode;
+  time_wheel_t* wheel = wheels + timer->wheel;
+  timer->prev = NULL;
+  timer->expireAt = taosGetTimestampMs() + delay;
 
-  if (cNode != NULL) {
-    cNode->prev = pObj;
-  }
+  pthread_mutex_lock(&wheel->mutex);
 
-  if (pNode != NULL) {
-    pNode->next = pObj;
-  } else {
-    pList->head = pObj;
+  uint32_t idx = 0;
+  if (timer->expireAt > wheel->nextScanAt) {
+    // adjust delay according to next scan time of this wheel
+    // so that the timer is not fired earlier than desired.
+    delay = (uint32_t)(timer->expireAt - wheel->nextScanAt);
+    idx = (delay + wheel->resolution - 1) / wheel->resolution;
   }
 
-  pList->count++;
-  pCtrl->numOfTmrs++;
-
-  if (pthread_mutex_unlock(&pCtrl->mutex) != 0)
-    tmrError("%s mutex unlock failed, reason:%s", pCtrl->label, strerror(errno));
-
-  tmrTrace("%s %p, timer started, fp:%p, tmr_h:%p, index:%d, total:%d cindex:%d", pCtrl->label, param1, fp, pObj, index,
-           pCtrl->numOfTmrs, cindex);
+  timer->slot = (uint16_t)((wheel->index + idx + 1) % wheel->size);
+  tmr_obj_t* p = wheel->slots[timer->slot];
+  wheel->slots[timer->slot] = timer;
+  timer->next = p;
+  if (p != NULL) {
+    p->prev = timer;
+  }
 
-  return (tmr_h)pObj;
+  pthread_mutex_unlock(&wheel->mutex);
 }
 
-void taosTmrStop(tmr_h timerId) {
-  tmr_obj_t * pObj;
-  tmr_list_t *pList;
-  tmr_ctrl_t *pCtrl;
-
-  pObj = (tmr_obj_t *)timerId;
-  if (pObj == NULL) return;
-
-  pCtrl = pObj->pCtrl;
-  if (pCtrl == NULL) return;
-
-  if (pthread_mutex_lock(&pCtrl->mutex) != 0)
-    tmrError("%s mutex lock failed, reason:%s", pCtrl->label, strerror(errno));
-
-  if (pObj->timerId == timerId) {
-    pList = &(pCtrl->tmrList[pObj->index]);
-    if (pObj->prev) {
-      pObj->prev->next = pObj->next;
-    } else {
-      pList->head = pObj->next;
+static bool removeFromWheel(tmr_obj_t* timer) {
+  if (timer->wheel >= tListLen(wheels)) {
+    return false;
+  }
+  time_wheel_t* wheel = wheels + timer->wheel;
+
+  bool removed = false;
+  pthread_mutex_lock(&wheel->mutex);
+  // other thread may modify timer->wheel, check again.
+  if (timer->wheel < tListLen(wheels)) {
+    if (timer->prev != NULL) {
+      timer->prev->next = timer->next;
     }
-
-    if (pObj->next) {
-      pObj->next->prev = pObj->prev;
+    if (timer->next != NULL) {
+      timer->next->prev = timer->prev;
     }
-
-    pList->count--;
-    pObj->timerId = NULL;
-    pCtrl->numOfTmrs--;
-
-    tmrTrace("%s %p, timer stopped, fp:%p, tmr_h:%p, total:%d", pCtrl->label, pObj->param1, pObj->fp, pObj,
-             pCtrl->numOfTmrs);
-    tmrMemPoolFree(pCtrl->poolHandle, (char *)(pObj));
+    if (timer == wheel->slots[timer->slot]) {
+      wheel->slots[timer->slot] = timer->next;
+    }
+    timer->wheel = tListLen(wheels);
+    timer->next = NULL;
+    timer->prev = NULL;
+    timerDecRef(timer);
+    removed = true;
   }
+  pthread_mutex_unlock(&wheel->mutex);
 
-  pthread_mutex_unlock(&pCtrl->mutex);
+  return removed;
 }
 
-void taosTmrStopA(tmr_h *timerId) {
-  tmr_obj_t * pObj;
-  tmr_list_t *pList;
-  tmr_ctrl_t *pCtrl;
+static void processExpiredTimer(void* handle, void* arg) {
+  tmr_obj_t* timer = (tmr_obj_t*)handle;
+  timer->executedBy = taosGetPthreadId();
+  uint8_t state = __sync_val_compare_and_swap_8(&timer->state, TIMER_STATE_WAITING, TIMER_STATE_EXPIRED);
+  if (state == TIMER_STATE_WAITING) {
+    const char* fmt = "timer[label=%s, id=%lld, fp=%p, param=%p] execution start.";
+    tmrTrace(fmt, timer->ctrl->label, timer->id, timer->fp, timer->param);
 
-  pObj = *(tmr_obj_t **)timerId;
-  if (pObj == NULL) return;
+    (*timer->fp)(timer->param, (tmr_h)timer->id);
+    atomic_store_8(&timer->state, TIMER_STATE_STOPPED);
 
-  pCtrl = pObj->pCtrl;
-  if (pCtrl == NULL) return;
-
-  if (pthread_mutex_lock(&pCtrl->mutex) != 0)
-    tmrError("%s mutex lock failed, reason:%s", pCtrl->label, strerror(errno));
-
-  if (pObj->timerId == pObj) {
-    pList = &(pCtrl->tmrList[pObj->index]);
-    if (pObj->prev) {
-      pObj->prev->next = pObj->next;
-    } else {
-      pList->head = pObj->next;
-    }
+    fmt = "timer[label=%s, id=%lld, fp=%p, param=%p] execution end.";
+    tmrTrace(fmt, timer->ctrl->label, timer->id, timer->fp, timer->param);
+  }
+  removeTimer(timer->id);
+  timerDecRef(timer);
+}
 
-    if (pObj->next) {
-      pObj->next->prev = pObj->prev;
-    }
+static void addToExpired(tmr_obj_t* head) {
+  const char* fmt = "timer[label=%s, id=%lld, fp=%p, param=%p] expired";
 
-    pList->count--;
-    pObj->timerId = NULL;
-    pCtrl->numOfTmrs--;
+  while (head != NULL) {
+    tmrTrace(fmt, head->ctrl->label, head->id, head->fp, head->param);
 
-    tmrTrace("%s %p, timer stopped atomiclly, fp:%p, tmr_h:%p, total:%d", pCtrl->label, pObj->param1, pObj->fp, pObj,
-             pCtrl->numOfTmrs);
-    tmrMemPoolFree(pCtrl->poolHandle, (char *)(pObj));
+    tmr_obj_t* next = head->next;
+    SSchedMsg  schedMsg;
+    schedMsg.fp = NULL;
+    schedMsg.tfp = processExpiredTimer;
+    schedMsg.ahandle = head;
+    schedMsg.thandle = NULL;
+    taosScheduleTask(tmrQhandle, &schedMsg);
+    head = next;
+  }
+}
 
-    *(tmr_obj_t **)timerId = NULL;
+static uintptr_t doStartTimer(tmr_obj_t* timer, TAOS_TMR_CALLBACK fp, int mseconds, void* param, tmr_ctrl_t* ctrl) {
+  uintptr_t id = getNextTimerId();
+  timer->id = id;
+  timer->state = TIMER_STATE_WAITING;
+  timer->fp = fp;
+  timer->param = param;
+  timer->ctrl = ctrl;
+  addTimer(timer);
+
+  const char* fmt = "timer[label=%s, id=%lld, fp=%p, param=%p] started";
+  tmrTrace(fmt, ctrl->label, timer->id, timer->fp, timer->param);
+
+  if (mseconds == 0) {
+    timer->wheel = tListLen(wheels);
+    timerAddRef(timer);
+    addToExpired(timer);
   } else {
-    tmrTrace("%s %p, timer stopped atomiclly, fp:%p, tmr_h:%p, total:%d", pCtrl->label, pObj->param1, pObj->fp, pObj,
-             pCtrl->numOfTmrs);
+    addToWheel(timer, mseconds);
   }
 
-  pthread_mutex_unlock(&pCtrl->mutex);
+  // note: use `timer->id` here is unsafe as `timer` may already be freed
+  return id;
 }
 
-void taosTmrReset(void (*fp)(void *, void *), int mseconds, void *param1, void *handle, tmr_h *pTmrId) {
-  tmr_obj_t * pObj, *cNode, *pNode;
-  tmr_list_t *pList;
-  int         index, period;
-  tmr_ctrl_t *pCtrl = (tmr_ctrl_t *)handle;
-
-  if (handle == NULL) return;
-  if (pTmrId == NULL) return;
-
-  period = mseconds / pCtrl->resolution;
-  if (pthread_mutex_lock(&pCtrl->mutex) != 0)
-    tmrError("%s mutex lock failed, reason:%s", pCtrl->label, strerror(errno));
+tmr_h taosTmrStart(TAOS_TMR_CALLBACK fp, int mseconds, void* param, void* handle) {
+  tmr_ctrl_t* ctrl = (tmr_ctrl_t*)handle;
+  if (ctrl == NULL || ctrl->label[0] == 0) {
+    return NULL;
+  }
 
-  pObj = (tmr_obj_t *)(*pTmrId);
+  tmr_obj_t* timer = (tmr_obj_t*)calloc(1, sizeof(tmr_obj_t));
+  if (timer == NULL) {
+    tmrError("failed to allocated memory for new timer object.");
+    return NULL;
+  }
 
-  if (pObj && pObj->timerId == *pTmrId) {
-    // exist, stop it first
-    pList = &(pCtrl->tmrList[pObj->index]);
-    if (pObj->prev) {
-      pObj->prev->next = pObj->next;
-    } else {
-      pList->head = pObj->next;
-    }
+  return (tmr_h)doStartTimer(timer, fp, mseconds, param, ctrl);
+}
 
-    if (pObj->next) {
-      pObj->next->prev = pObj->prev;
+static void taosTimerLoopFunc(int signo) {
+  int64_t now = taosGetTimestampMs();
+
+  for (int i = 0; i < tListLen(wheels); i++) {
+    // `expried` is a temporary expire list.
+    // expired timers are first add to this list, then move
+    // to expired queue as a batch to improve performance.
+    // note this list is used as a stack in this function.
+    tmr_obj_t* expired = NULL;
+
+    time_wheel_t* wheel = wheels + i;
+    while (now >= wheel->nextScanAt) {
+      pthread_mutex_lock(&wheel->mutex);
+      wheel->index = (wheel->index + 1) % wheel->size;
+      tmr_obj_t* timer = wheel->slots[wheel->index];
+      while (timer != NULL) {
+        tmr_obj_t* next = timer->next;
+        if (now < timer->expireAt) {
+          timer = next;
+          continue;
+        }
+
+        // remove from the wheel
+        if (timer->prev == NULL) {
+          wheel->slots[wheel->index] = next;
+          if (next != NULL) {
+            next->prev = NULL;
+          }
+        } else {
+          timer->prev->next = next;
+          if (next != NULL) {
+            next->prev = timer->prev;
+          }
+        }
+        timer->wheel = tListLen(wheels);
+
+        // add to temporary expire list
+        timer->next = expired;
+        timer->prev = NULL;
+        if (expired != NULL) {
+          expired->prev = timer;
+        }
+        expired = timer;
+
+        timer = next;
+      }
+      pthread_mutex_unlock(&wheel->mutex);
+      wheel->nextScanAt += wheel->resolution;
     }
 
-    pList->count--;
-    pObj->timerId = NULL;
-    pCtrl->numOfTmrs--;
-  } else {
-    // timer not there, or already expired
-    pObj = (tmr_obj_t *)tmrMemPoolMalloc(pCtrl->poolHandle);
-    *pTmrId = pObj;
-
-    if (pObj == NULL) {
-      tmrError("%s failed to allocate timer, max:%d allocated:%d", pCtrl->label, pCtrl->maxNumOfTmrs, pCtrl->numOfTmrs);
-      pthread_mutex_unlock(&pCtrl->mutex);
-      return;
-    }
+    addToExpired(expired);
   }
+}
 
-  pObj->cycle = period / pCtrl->numOfPeriods;
-  pObj->param1 = param1;
-  pObj->fp = fp;
-  pObj->timerId = pObj;
-  pObj->pCtrl = pCtrl;
+static bool doStopTimer(tmr_obj_t* timer, uint8_t state) {
+  bool reusable = false;
 
-  index = (period + pCtrl->periodsFromStart) % pCtrl->numOfPeriods;
-  pList = &(pCtrl->tmrList[index]);
+  if (state == TIMER_STATE_WAITING) {
+    if (removeFromWheel(timer)) {
+      removeTimer(timer->id);
+      // only safe to reuse the timer when timer is removed from the wheel.
+      // we cannot guarantee the thread safety of the timr in all other cases.
+      reusable = true;
+    }
+    const char* fmt = "timer[label=%s, id=%lld, fp=%p, param=%p] is cancelled.";
+    tmrTrace(fmt, timer->ctrl->label, timer->id, timer->fp, timer->param);
+  } else if (state != TIMER_STATE_EXPIRED) {
+    // timer already stopped or cancelled, has nothing to do in this case
+  } else if (timer->executedBy == taosGetPthreadId()) {
+    // taosTmrReset is called in the timer callback, should do nothing in this
+    // case to avoid dead lock. note taosTmrReset must be the last statement
+    // of the callback funtion, will be a bug otherwise.
+  } else {
+    assert(timer->executedBy != taosGetPthreadId());
 
-  pObj->index = index;
-  cNode = pList->head;
-  pNode = NULL;
+    const char* fmt = "timer[label=%s, id=%lld, fp=%p, param=%p] fired, waiting...";
+    tmrTrace(fmt, timer->ctrl->label, timer->id, timer->fp, timer->param);
 
-  while (cNode != NULL) {
-    if (cNode->cycle < pObj->cycle) {
-      pNode = cNode;
-      cNode = cNode->next;
-    } else {
-      break;
+    for (int i = 1; atomic_load_8(&timer->state) != TIMER_STATE_STOPPED; i++) {
+      if (i % 1000 == 0) {
+        sched_yield();
+      }
     }
-  }
-
-  pObj->next = cNode;
-  pObj->prev = pNode;
 
-  if (cNode != NULL) {
-    cNode->prev = pObj;
+    fmt = "timer[label=%s, id=%lld, fp=%p, param=%p] stopped.";
+    tmrTrace(fmt, timer->ctrl->label, timer->id, timer->fp, timer->param);
   }
 
-  if (pNode != NULL) {
-    pNode->next = pObj;
-  } else {
-    pList->head = pObj;
-  }
+  return reusable;
+}
 
-  pList->count++;
-  pCtrl->numOfTmrs++;
+bool taosTmrStop(tmr_h timerId) {
+  uintptr_t id = (uintptr_t)timerId;
 
-  if (pthread_mutex_unlock(&pCtrl->mutex) != 0)
-    tmrError("%s mutex unlock failed, reason:%s", pCtrl->label, strerror(errno));
+  tmr_obj_t* timer = findTimer(id);
+  if (timer == NULL) {
+    tmrTrace("timer[id=%lld] does not exist", id);
+    return false;
+  }
 
-  tmrTrace("%s %p, timer is reset, fp:%p, tmr_h:%p, index:%d, total:%d numOfFree:%d", pCtrl->label, param1, fp, pObj,
-           index, pCtrl->numOfTmrs, ((pool_t *)pCtrl->poolHandle)->numOfFree);
+  uint8_t state = __sync_val_compare_and_swap_8(&timer->state, TIMER_STATE_WAITING, TIMER_STATE_CANCELED);
+  doStopTimer(timer, state);
+  timerDecRef(timer);
 
-  return;
+  return state == TIMER_STATE_WAITING;
 }
 
-void taosTmrList(void *handle) {
-  int         i;
-  tmr_list_t *pList;
-  tmr_obj_t * pObj;
-  tmr_ctrl_t *pCtrl = (tmr_ctrl_t *)handle;
-
-  for (i = 0; i < pCtrl->numOfPeriods; ++i) {
-    pList = &(pCtrl->tmrList[i]);
-    pObj = pList->head;
-    if (!pObj) continue;
-    printf("\nindex=%d count:%d\n", i, pList->count);
-    while (pObj) {
-      pObj = pObj->next;
-    }
-  }
+bool taosTmrStopA(tmr_h* timerId) {
+  bool ret = taosTmrStop(*timerId);
+  *timerId = NULL;
+  return ret;
 }
 
-mpool_h tmrMemPoolInit(int numOfBlock, int blockSize) {
-  int     i;
-  pool_t *pool_p;
-
-  if (numOfBlock <= 1 || blockSize <= 1) {
-    tmrError("invalid parameter in memPoolInit\n");
+bool taosTmrReset(TAOS_TMR_CALLBACK fp, int mseconds, void* param, void* handle, tmr_h* pTmrId) {
+  tmr_ctrl_t* ctrl = (tmr_ctrl_t*)handle;
+  if (ctrl == NULL || ctrl->label[0] == 0) {
     return NULL;
   }
 
-  pool_p = (pool_t *)malloc(sizeof(pool_t));
-  if (pool_p == NULL) {
-    tmrError("mempool malloc failed\n");
-    return NULL;
+  uintptr_t  id = (uintptr_t)*pTmrId;
+  bool       stopped = false;
+  tmr_obj_t* timer = findTimer(id);
+  if (timer == NULL) {
+    tmrTrace("timer[id=%lld] does not exist", id);
   } else {
-    memset(pool_p, 0, sizeof(pool_t));
+    uint8_t state = __sync_val_compare_and_swap_8(&timer->state, TIMER_STATE_WAITING, TIMER_STATE_CANCELED);
+    if (!doStopTimer(timer, state)) {
+      timerDecRef(timer);
+      timer = NULL;
+    }
+    stopped = state == TIMER_STATE_WAITING;
   }
 
-  pool_p->blockSize = blockSize;
-  pool_p->numOfBlock = numOfBlock;
-  pool_p->pool = (char *)malloc(blockSize * numOfBlock);
-  pool_p->freeList = (int *)malloc(sizeof(int) * numOfBlock);
-
-  if (pool_p->pool == NULL || pool_p->freeList == NULL) {
-    tmrError("failed to allocate memory\n");
-    tfree(pool_p->freeList);
-    tfree(pool_p->pool);
-    free(pool_p);
-    return NULL;
+  if (timer == NULL) {
+    *pTmrId = taosTmrStart(fp, mseconds, param, handle);
+    return stopped;
   }
-  memset(pool_p->pool, 0, blockSize * numOfBlock);
 
-  for (i = 0; i < pool_p->numOfBlock; ++i) pool_p->freeList[i] = i;
+  tmrTrace("timer[id=%lld] is reused", timer->id);
+
+  // wait until there's no other reference to this timer,
+  // so that we can reuse this timer safely.
+  for (int i = 1; atomic_load_8(&timer->refCount) > 1; ++i) {
+    if (i % 1000 == 0) {
+      sched_yield();
+    }
+  }
 
-  pool_p->first = 0;
-  pool_p->numOfFree = pool_p->numOfBlock;
+  assert(timer->refCount == 1);
+  memset(timer, 0, sizeof(*timer));
+  *pTmrId = (tmr_h)doStartTimer(timer, fp, mseconds, param, ctrl);
 
-  return (mpool_h)pool_p;
+  return stopped;
 }
 
-char *tmrMemPoolMalloc(mpool_h handle) {
-  char *  pos = NULL;
-  pool_t *pool_p = (pool_t *)handle;
+static void taosTmrModuleInit(void) {
+  for (int i = 0; i < tListLen(tmrCtrls) - 1; ++i) {
+    tmr_ctrl_t* ctrl = tmrCtrls + i;
+    ctrl->next = ctrl + 1;
+  }
+  unusedTmrCtrl = tmrCtrls;
+
+  pthread_mutex_init(&tmrCtrlMutex, NULL);
 
-  if (pool_p->numOfFree <= 0 || pool_p->numOfFree > pool_p->numOfBlock) {
-    tmrError("mempool: out of memory, numOfFree:%d, numOfBlock:%d", pool_p->numOfFree, pool_p->numOfBlock);
-  } else {
-    pos = pool_p->pool + pool_p->blockSize * (pool_p->freeList[pool_p->first]);
-    pool_p->first++;
-    pool_p->first = pool_p->first % pool_p->numOfBlock;
-    pool_p->numOfFree--;
+  int64_t now = taosGetTimestampMs();
+  for (int i = 0; i < tListLen(wheels); i++) {
+    time_wheel_t* wheel = wheels + i;
+    if (pthread_mutex_init(&wheel->mutex, NULL) != 0) {
+      tmrError("failed to create the mutex for wheel, reason:%s", strerror(errno));
+      return;
+    }
+    wheel->nextScanAt = now + wheel->resolution;
+    wheel->index = 0;
+    wheel->slots = (tmr_obj_t**)calloc(wheel->size, sizeof(tmr_obj_t*));
+    if (wheel->slots == NULL) {
+      tmrError("failed to allocate wheel slots");
+      return;
+    }
+    timerMap.size += wheel->size;
   }
 
-  return pos;
-}
+  timerMap.count = 0;
+  timerMap.slots = (timer_list_t*)calloc(timerMap.size, sizeof(timer_list_t));
+  if (timerMap.slots == NULL) {
+    tmrError("failed to allocate hash map");
+    return;
+  }
 
-void tmrMemPoolFree(mpool_h handle, char *pMem) {
-  int     index;
-  pool_t *pool_p = (pool_t *)handle;
+  tmrQhandle = taosInitScheduler(10000, taosTmrThreads, "tmr");
+  taosInitTimer(taosTimerLoopFunc, MSECONDS_PER_TICK);
 
-  if (pMem == NULL) return;
+  tmrTrace("timer module is initialized, number of threads: %d", taosTmrThreads);
+}
 
-  index = (int)(pMem - pool_p->pool) / pool_p->blockSize;
+void* taosTmrInit(int maxNumOfTmrs, int resolution, int longest, const char* label) {
+  pthread_once(&tmrModuleInit, taosTmrModuleInit);
 
-  if (index < 0 || index >= pool_p->numOfBlock) {
-    tmrError("tmr mempool: error, invalid address:%p\n", pMem);
-  } else {
-    memset(pMem, 0, pool_p->blockSize);
-    pool_p->freeList[(pool_p->first + pool_p->numOfFree) % pool_p->numOfBlock] = index;
-    pool_p->numOfFree++;
+  pthread_mutex_lock(&tmrCtrlMutex);
+  tmr_ctrl_t* ctrl = unusedTmrCtrl;
+  if (ctrl != NULL) {
+    unusedTmrCtrl = ctrl->next;
   }
+  pthread_mutex_unlock(&tmrCtrlMutex);
+
+  if (ctrl == NULL) {
+    tmrError("too many timer controllers, failed to create timer controller[label=%s].", label);
+    return NULL;
+  }
+
+  strncpy(ctrl->label, label, sizeof(ctrl->label));
+  ctrl->label[sizeof(ctrl->label) - 1] = 0;
+  tmrTrace("timer controller[label=%s] is initialized.", label);
+  return ctrl;
 }
 
-void tmrMemPoolCleanUp(mpool_h handle) {
-  pool_t *pool_p = (pool_t *)handle;
-  if (pool_p == NULL) return;
+void taosTmrCleanUp(void* handle) {
+  tmr_ctrl_t* ctrl = (tmr_ctrl_t*)handle;
+  assert(ctrl != NULL && ctrl->label[0] != 0);
+
+  tmrTrace("timer controller[label=%s] is cleaned up.", ctrl->label);
+  ctrl->label[0] = 0;
 
-  if (pool_p->pool) free(pool_p->pool);
-  if (pool_p->freeList) free(pool_p->freeList);
-  memset(&pool_p, 0, sizeof(pool_p));
-  free(pool_p);
+  pthread_mutex_lock(&tmrCtrlMutex);
+  ctrl->next = unusedTmrCtrl;
+  unusedTmrCtrl = ctrl;
+  pthread_mutex_unlock(&tmrCtrlMutex);
 }