diff --git a/docs/reports/STM32F407-168-GCC.txt b/docs/reports/STM32F407-168-GCC.txt
index e7b27daa6..1ac46ae2d 100644
--- a/docs/reports/STM32F407-168-GCC.txt
+++ b/docs/reports/STM32F407-168-GCC.txt
@@ -5,8 +5,8 @@ Settings: SYSCLK=168, ACR=0x705 (5 wait states)
 
 *** ChibiOS/RT test suite
 ***
-*** Kernel:       2.4.0
-*** Compiled:     Jan 15 2012 - 20:10:20
+*** Kernel:       2.5.0
+*** Compiled:     Feb  6 2012 - 20:30:43
 *** Compiler:     GCC 4.6.2
 *** Architecture: ARMv7-ME
 *** Core Variant: Cortex-M4
@@ -100,11 +100,11 @@ Settings: SYSCLK=168, ACR=0x705 (5 wait states)
 --- Result: SUCCESS
 ----------------------------------------------------------------------------
 --- Test Case 11.1 (Benchmark, messages #1)
---- Score : 749359 msgs/S, 1498718 ctxswc/S
+--- Score : 752723 msgs/S, 1505446 ctxswc/S
 --- Result: SUCCESS
 ----------------------------------------------------------------------------
 --- Test Case 11.2 (Benchmark, messages #2)
---- Score : 617119 msgs/S, 1234238 ctxswc/S
+--- Score : 617124 msgs/S, 1234248 ctxswc/S
 --- Result: SUCCESS
 ----------------------------------------------------------------------------
 --- Test Case 11.3 (Benchmark, messages #3)
@@ -112,23 +112,23 @@ Settings: SYSCLK=168, ACR=0x705 (5 wait states)
 --- Result: SUCCESS
 ----------------------------------------------------------------------------
 --- Test Case 11.4 (Benchmark, context switch)
---- Score : 2491424 ctxswc/S
+--- Score : 2528968 ctxswc/S
 --- Result: SUCCESS
 ----------------------------------------------------------------------------
 --- Test Case 11.5 (Benchmark, threads, full cycle)
---- Score : 451234 threads/S
+--- Score : 448823 threads/S
 --- Result: SUCCESS
 ----------------------------------------------------------------------------
 --- Test Case 11.6 (Benchmark, threads, create only)
---- Score : 635830 threads/S
+--- Score : 635833 threads/S
 --- Result: SUCCESS
 ----------------------------------------------------------------------------
 --- Test Case 11.7 (Benchmark, mass reschedule, 5 threads)
---- Score : 193114 reschedules/S, 1158684 ctxswc/S
+--- Score : 193383 reschedules/S, 1160298 ctxswc/S
 --- Result: SUCCESS
 ----------------------------------------------------------------------------
 --- Test Case 11.8 (Benchmark, round robin context switching)
---- Score : 1367460 ctxswc/S
+--- Score : 1356420 ctxswc/S
 --- Result: SUCCESS
 ----------------------------------------------------------------------------
 --- Test Case 11.9 (Benchmark, I/O Queues throughput)
@@ -148,7 +148,7 @@ Settings: SYSCLK=168, ACR=0x705 (5 wait states)
 --- Result: SUCCESS
 ----------------------------------------------------------------------------
 --- Test Case 11.13 (Benchmark, RAM footprint)
---- System: 376 bytes
+--- System: 372 bytes
 --- Thread: 72 bytes
 --- Timer : 20 bytes
 --- Semaph: 12 bytes
diff --git a/os/kernel/include/chschd.h b/os/kernel/include/chschd.h
index 54076ec56..215398659 100644
--- a/os/kernel/include/chschd.h
+++ b/os/kernel/include/chschd.h
@@ -95,9 +95,6 @@ typedef struct {
   Thread                *r_older;   /**< @brief Older registry element.     */
 #endif
   /* End of the fields shared with the Thread structure.*/
-#if (CH_TIME_QUANTUM > 0) || defined(__DOXYGEN__)
-  cnt_t                 r_preempt;  /**< @brief Round robin counter.        */
-#endif
   Thread                *r_current; /**< @brief The currently running
                                                 thread.                     */
 } ReadyList;
@@ -154,6 +151,12 @@ extern "C" {
 #if !defined(PORT_OPTIMIZED_ISPREEMPTIONREQUIRED)
   bool_t chSchIsPreemptionRequired(void);
 #endif
+#if !defined(PORT_OPTIMIZED_DORESCHEDULEBEHIND) || defined(__DOXYGEN__)
+  void chSchDoRescheduleBehind(void);
+#endif
+#if !defined(PORT_OPTIMIZED_DORESCHEDULEAHEAD) || defined(__DOXYGEN__)
+  void chSchDoRescheduleAhead(void);
+#endif
 #if !defined(PORT_OPTIMIZED_DORESCHEDULE)
   void chSchDoReschedule(void);
 #endif
@@ -197,7 +200,7 @@ extern "C" {
 #if !defined(PORT_OPTIMIZED_DOYIELDS) || defined(__DOXYGEN__)
 #define chSchDoYieldS() {                                                   \
   if (chSchCanYieldS())                                                     \
-    chSchDoReschedule();                                                    \
+    chSchDoRescheduleBehind();                                              \
 }
 #endif /* !defined(PORT_OPTIMIZED_DOYIELDS) */
 
@@ -212,19 +215,19 @@ extern "C" {
 #define chSchPreemption() {                                                 \
   tprio_t p1 = firstprio(&rlist.r_queue);                                   \
   tprio_t p2 = currp->p_prio;                                               \
-  if (rlist.r_preempt) {                                                    \
+  if (currp->p_preempt) {                                                   \
     if (p1 > p2)                                                            \
-      chSchDoReschedule();                                                  \
+      chSchDoRescheduleAhead();                                             \
   }                                                                         \
   else {                                                                    \
     if (p1 >= p2)                                                           \
-      chSchDoReschedule();                                                  \
+      chSchDoRescheduleBehind();                                            \
   }                                                                         \
 }
 #else /* CH_TIME_QUANTUM == 0 */
 #define chSchPreemption() {                                                 \
   if (p1 >= p2)                                                             \
-    chSchDoReschedule();                                                    \
+    chSchDoRescheduleAhead();                                               \
 }
 #endif /* CH_TIME_QUANTUM == 0 */
 /** @} */
diff --git a/os/kernel/include/chthreads.h b/os/kernel/include/chthreads.h
index 66b593818..421a3e23f 100644
--- a/os/kernel/include/chthreads.h
+++ b/os/kernel/include/chthreads.h
@@ -121,6 +121,12 @@ struct Thread {
    * @brief References to this thread.
    */
   trefs_t               p_refs;
+#endif
+  /**
+   * @brief Number of ticks remaining to this thread.
+   */
+#if (CH_TIME_QUANTUM > 0) || defined(__DOXYGEN__)
+  tslices_t             p_preempt;
 #endif
 #if CH_DBG_THREADS_PROFILING || defined(__DOXYGEN__)
   /**
diff --git a/os/kernel/src/chschd.c b/os/kernel/src/chschd.c
index 4acc500af..3dd226b1b 100644
--- a/os/kernel/src/chschd.c
+++ b/os/kernel/src/chschd.c
@@ -49,9 +49,6 @@ void _scheduler_init(void) {
 
   queue_init(&rlist.r_queue);
   rlist.r_prio = NOPRIO;
-#if CH_TIME_QUANTUM > 0
-  rlist.r_preempt = CH_TIME_QUANTUM;
-#endif
 #if CH_USE_REGISTRY
   rlist.r_newer = rlist.r_older = (Thread *)&rlist;
 #endif
@@ -59,6 +56,8 @@ void _scheduler_init(void) {
 
 /**
  * @brief   Inserts a thread in the Ready List.
+ * @details The thread is positioned behind all threads with higher or equal
+ *          priority.
  * @pre     The thread must not be already inserted in any list through its
  *          @p p_next and @p p_prev or list corruption would occur.
  * @post    This function does not reschedule so a call to a rescheduling
@@ -111,7 +110,9 @@ void chSchGoSleepS(tstate_t newstate) {
 
   (otp = currp)->p_state = newstate;
 #if CH_TIME_QUANTUM > 0
-  rlist.r_preempt = CH_TIME_QUANTUM;
+  /* The thread is renouncing its remaining time slices so it will have a new
+     time quantum when it will wakeup.*/
+  otp->p_preempt = CH_TIME_QUANTUM;
 #endif
   setcurrp(fifo_remove(&rlist.r_queue));
   currp->p_state = THD_STATE_CURRENT;
@@ -222,9 +223,6 @@ void chSchWakeupS(Thread *ntp, msg_t msg) {
     chSchReadyI(ntp);
   else {
     Thread *otp = chSchReadyI(currp);
-#if CH_TIME_QUANTUM > 0
-    rlist.r_preempt = CH_TIME_QUANTUM;
-#endif
     setcurrp(ntp);
     ntp->p_state = THD_STATE_CURRENT;
     chSysSwitch(ntp, otp);
@@ -237,7 +235,7 @@ void chSchWakeupS(Thread *ntp, msg_t msg) {
  * @details If a thread with a higher priority than the current thread is in
  *          the ready list then make the higher priority thread running.
  *
- * @iclass
+ * @sclass
  */
 #if !defined(PORT_OPTIMIZED_RESCHEDULES) || defined(__DOXYGEN__)
 void chSchRescheduleS(void) {
@@ -245,7 +243,7 @@ void chSchRescheduleS(void) {
   chDbgCheckClassS();
 
   if (chSchIsRescRequiredI())
-    chSchDoReschedule();
+    chSchDoRescheduleAhead();
 }
 #endif /* !defined(PORT_OPTIMIZED_RESCHEDULES) */
 
@@ -271,7 +269,7 @@ bool_t chSchIsPreemptionRequired(void) {
      if the first thread on the ready queue has a higher priority.
      Otherwise, if the running thread has used up its time quantum, reschedule
      if the first thread on the ready queue has equal or higher priority.*/
-  return rlist.r_preempt ? p1 > p2 : p1 >= p2;
+  return currp->r_preempt ? p1 > p2 : p1 >= p2;
 #else
   /* If the round robin preemption feature is not enabled then performs a
      simpler comparison.*/
@@ -282,6 +280,65 @@ bool_t chSchIsPreemptionRequired(void) {
 
 /**
  * @brief   Switches to the first thread on the runnable queue.
+ * @details The current thread is positioned in the ready list behind all
+ *          threads having the same priority. The thread regains its time
+ *          quantum.
+ * @note    Not a user function, it is meant to be invoked by the scheduler
+ *          itself or from within the port layer.
+ *
+ * @special
+ */
+#if !defined(PORT_OPTIMIZED_DORESCHEDULEBEHIND) || defined(__DOXYGEN__)
+void chSchDoRescheduleBehind(void) {
+  Thread *otp;
+
+  otp = currp;
+  /* Picks the first thread from the ready queue and makes it current.*/
+  setcurrp(fifo_remove(&rlist.r_queue));
+  currp->p_state = THD_STATE_CURRENT;
+  otp->p_preempt = CH_TIME_QUANTUM;
+  chSchReadyI(otp);
+  chSysSwitch(currp, otp);
+}
+#endif /* !defined(PORT_OPTIMIZED_DORESCHEDULEBEHIND) */
+
+/**
+ * @brief   Switches to the first thread on the runnable queue.
+ * @details The current thread is positioned in the ready list ahead of all
+ *          threads having the same priority.
+ * @note    Not a user function, it is meant to be invoked by the scheduler
+ *          itself or from within the port layer.
+ *
+ * @special
+ */
+#if !defined(PORT_OPTIMIZED_DORESCHEDULEAHEAD) || defined(__DOXYGEN__)
+void chSchDoRescheduleAhead(void) {
+  Thread *otp, *cp;
+
+  otp = currp;
+  /* Picks the first thread from the ready queue and makes it current.*/
+  setcurrp(fifo_remove(&rlist.r_queue));
+  currp->p_state = THD_STATE_CURRENT;
+
+  otp->p_state = THD_STATE_READY;
+  cp = (Thread *)&rlist.r_queue;
+  do {
+    cp = cp->p_next;
+  } while (cp->p_prio > otp->p_prio);
+  /* Insertion on p_prev.*/
+  otp->p_next = cp;
+  otp->p_prev = cp->p_prev;
+  otp->p_prev->p_next = cp->p_prev = otp;
+
+  chSysSwitch(currp, otp);
+}
+#endif /* !defined(PORT_OPTIMIZED_DORESCHEDULEAHEAD) */
+
+/**
+ * @brief   Switches to the first thread on the runnable queue.
+ * @details The current thread is positioned in the ready list behind or
+ *          ahead of all threads having the same priority depending on
+ *          if it used its whole time slice.
  * @note    Not a user function, it is meant to be invoked by the scheduler
  *          itself or from within the port layer.
  *
@@ -289,17 +346,25 @@ bool_t chSchIsPreemptionRequired(void) {
  */
 #if !defined(PORT_OPTIMIZED_DORESCHEDULE) || defined(__DOXYGEN__)
 void chSchDoReschedule(void) {
-  Thread *otp;
 
 #if CH_TIME_QUANTUM > 0
-  rlist.r_preempt = CH_TIME_QUANTUM;
-#endif
-  otp = currp;
-  /* Picks the first thread from the ready queue and makes it current.*/
-  setcurrp(fifo_remove(&rlist.r_queue));
-  currp->p_state = THD_STATE_CURRENT;
-  chSchReadyI(otp);
-  chSysSwitch(currp, otp);
+  /* If CH_TIME_QUANTUM is enabled then there are two different scenarios to
+     handle on preemption: time quantum elapsed or not.*/
+  if (currp->p_preempt == 0) {
+    /* The thread consumed its time quantum so it is enqueued behind threads
+       with same priority level, however, it acquires a new time quantum.*/
+    chSchDoRescheduleBehind();
+  }
+  else {
+    /* The thread didn't consume all its time quantum so it is put ahead of
+       threads with equal priority and does not acquire a new time quantum.*/
+    chSchDoRescheduleAhead();
+  }
+#else /* !(CH_TIME_QUANTUM > 0) */
+  /* If the round-robin mechanism is disabled then the thread goes always
+     ahead of its peers.*/
+  chSchDoRescheduleAhead();
+#endif /* !(CH_TIME_QUANTUM > 0) */
 }
 #endif /* !defined(PORT_OPTIMIZED_DORESCHEDULE) */
 
diff --git a/os/kernel/src/chsys.c b/os/kernel/src/chsys.c
index 41946cdaf..e433a8e42 100644
--- a/os/kernel/src/chsys.c
+++ b/os/kernel/src/chsys.c
@@ -129,9 +129,9 @@ void chSysTimerHandlerI(void) {
 
 #if CH_TIME_QUANTUM > 0
   /* Running thread has not used up quantum yet? */
-  if (rlist.r_preempt > 0)
+  if (currp->p_preempt > 0)
     /* Decrement remaining quantum.*/
-    rlist.r_preempt--;
+    currp->p_preempt--;
 #endif
 #if CH_DBG_THREADS_PROFILING
   currp->p_time++;
diff --git a/os/kernel/src/chthreads.c b/os/kernel/src/chthreads.c
index a73697eb4..eccf466d0 100644
--- a/os/kernel/src/chthreads.c
+++ b/os/kernel/src/chthreads.c
@@ -71,6 +71,9 @@ Thread *_thread_init(Thread *tp, tprio_t prio) {
   tp->p_prio = prio;
   tp->p_state = THD_STATE_SUSPENDED;
   tp->p_flags = THD_MEM_MODE_STATIC;
+#if CH_TIME_QUANTUM > 0
+  tp->p_preempt = CH_TIME_QUANTUM;
+#endif
 #if CH_USE_MUTEXES
   tp->p_realprio = prio;
   tp->p_mtxlist = NULL;
diff --git a/os/ports/GCC/ARM/chtypes.h b/os/ports/GCC/ARM/chtypes.h
index 41dffc938..eb0c04c77 100644
--- a/os/ports/GCC/ARM/chtypes.h
+++ b/os/ports/GCC/ARM/chtypes.h
@@ -42,6 +42,7 @@ typedef int32_t         bool_t;         /**< Fast boolean type.             */
 typedef uint8_t         tmode_t;        /**< Thread flags.                  */
 typedef uint8_t         tstate_t;       /**< Thread state.                  */
 typedef uint8_t         trefs_t;        /**< Thread references counter.     */
+typedef uint8_t         tslices_t;      /**< Thread time slices counter.    */
 typedef uint32_t        tprio_t;        /**< Thread priority.               */
 typedef int32_t         msg_t;          /**< Inter-thread message.          */
 typedef int32_t         eventid_t;      /**< Event Id.                      */
diff --git a/os/ports/GCC/ARMCMx/chcore.h b/os/ports/GCC/ARMCMx/chcore.h
index 7f97cde5d..b2cf4deaa 100644
--- a/os/ports/GCC/ARMCMx/chcore.h
+++ b/os/ports/GCC/ARMCMx/chcore.h
@@ -168,8 +168,8 @@ struct intctx {};
  * @brief   Inlineable version of this kernel function.
  */
 #define chSchIsPreemptionRequired()                                         \
-  (rlist.r_preempt ? firstprio(&rlist.r_queue) > currp->p_prio :            \
-                     firstprio(&rlist.r_queue) >= currp->p_prio)
+  (currp->p_preempt ? firstprio(&rlist.r_queue) > currp->p_prio :           \
+                      firstprio(&rlist.r_queue) >= currp->p_prio)
 #else /* CH_TIME_QUANTUM == 0 */
 #define chSchIsPreemptionRequired()                                         \
   (firstprio(&rlist.r_queue) > currp->p_prio)
diff --git a/os/ports/GCC/ARMCMx/chtypes.h b/os/ports/GCC/ARMCMx/chtypes.h
index 2105c7130..4d896fea0 100644
--- a/os/ports/GCC/ARMCMx/chtypes.h
+++ b/os/ports/GCC/ARMCMx/chtypes.h
@@ -40,6 +40,7 @@ typedef int32_t         bool_t;         /**< Fast boolean type.             */
 typedef uint8_t         tmode_t;        /**< Thread flags.                  */
 typedef uint8_t         tstate_t;       /**< Thread state.                  */
 typedef uint8_t         trefs_t;        /**< Thread references counter.     */
+typedef uint8_t         tslices_t;      /**< Thread time slices counter.    */
 typedef uint32_t        tprio_t;        /**< Thread priority.               */
 typedef int32_t         msg_t;          /**< Inter-thread message.          */
 typedef int32_t         eventid_t;      /**< Event Id.                      */
diff --git a/os/ports/GCC/AVR/chtypes.h b/os/ports/GCC/AVR/chtypes.h
index 3831f0f7c..0c8197823 100644
--- a/os/ports/GCC/AVR/chtypes.h
+++ b/os/ports/GCC/AVR/chtypes.h
@@ -42,6 +42,7 @@ typedef int8_t          bool_t;         /**< Fast boolean type.             */
 typedef uint8_t         tmode_t;        /**< Thread flags.                  */
 typedef uint8_t         tstate_t;       /**< Thread state.                  */
 typedef uint8_t         trefs_t;        /**< Thread references counter.     */
+typedef uint8_t         tslices_t;      /**< Thread time slices counter.    */
 typedef uint8_t         tprio_t;        /**< Thread priority.               */
 typedef int16_t         msg_t;          /**< Inter-thread message.          */
 typedef uint8_t         eventid_t;      /**< Event Id.                      */
diff --git a/os/ports/GCC/MSP430/chtypes.h b/os/ports/GCC/MSP430/chtypes.h
index cd35a341e..a56351016 100644
--- a/os/ports/GCC/MSP430/chtypes.h
+++ b/os/ports/GCC/MSP430/chtypes.h
@@ -42,6 +42,7 @@ typedef int16_t         bool_t;         /**< Fast boolean type.             */
 typedef uint8_t         tmode_t;        /**< Thread flags.                  */
 typedef uint8_t         tstate_t;       /**< Thread state.                  */
 typedef uint8_t         trefs_t;        /**< Thread references counter.     */
+typedef uint8_t         tslices_t;      /**< Thread time slices counter.    */
 typedef uint16_t        tprio_t;        /**< Thread priority.               */
 typedef int16_t         msg_t;          /**< Inter-thread message.          */
 typedef int16_t         eventid_t;      /**< Event Id.                      */
diff --git a/os/ports/GCC/PPC/chtypes.h b/os/ports/GCC/PPC/chtypes.h
index 88e9742b7..debc5f0f8 100644
--- a/os/ports/GCC/PPC/chtypes.h
+++ b/os/ports/GCC/PPC/chtypes.h
@@ -54,6 +54,7 @@ typedef int32_t             bool_t;         /**< Fast boolean type.         */
 typedef uint8_t             tmode_t;        /**< Thread flags.              */
 typedef uint8_t             tstate_t;       /**< Thread state.              */
 typedef uint8_t             trefs_t;        /**< Thread references counter. */
+typedef uint8_t             tslices_t;      /**< Thread time slices counter.    */
 typedef uint32_t            tprio_t;        /**< Thread priority.           */
 typedef int32_t             msg_t;          /**< Inter-thread message.      */
 typedef int32_t             eventid_t;      /**< Event Id.                  */
diff --git a/os/ports/GCC/SIMIA32/chtypes.h b/os/ports/GCC/SIMIA32/chtypes.h
index 693ade588..54d701044 100644
--- a/os/ports/GCC/SIMIA32/chtypes.h
+++ b/os/ports/GCC/SIMIA32/chtypes.h
@@ -34,6 +34,7 @@ typedef int32_t         bool_t;         /**< Fast boolean type.             */
 typedef uint8_t         tmode_t;        /**< Thread flags.                  */
 typedef uint8_t         tstate_t;       /**< Thread state.                  */
 typedef uint8_t         trefs_t;        /**< Thread references counter.     */
+typedef uint8_t         tslices_t;      /**< Thread time slices counter.    */
 typedef uint32_t        tprio_t;        /**< Thread priority.               */
 typedef int32_t         msg_t;          /**< Inter-thread message.          */
 typedef int32_t         eventid_t;      /**< Event Id.                      */
diff --git a/os/ports/IAR/ARMCMx/chtypes.h b/os/ports/IAR/ARMCMx/chtypes.h
index e8a6a7dc4..36e24e5c7 100644
--- a/os/ports/IAR/ARMCMx/chtypes.h
+++ b/os/ports/IAR/ARMCMx/chtypes.h
@@ -40,6 +40,7 @@ typedef int32_t         bool_t;         /**< Fast boolean type.             */
 typedef uint8_t         tmode_t;        /**< Thread flags.                  */
 typedef uint8_t         tstate_t;       /**< Thread state.                  */
 typedef uint8_t         trefs_t;        /**< Thread references counter.     */
+typedef uint8_t         tslices_t;      /**< Thread time slices counter.    */
 typedef uint32_t        tprio_t;        /**< Thread priority.               */
 typedef int32_t         msg_t;          /**< Inter-thread message.          */
 typedef int32_t         eventid_t;      /**< Event Id.                      */
diff --git a/os/ports/RC/STM8/chtypes.h b/os/ports/RC/STM8/chtypes.h
index 3a0efe78a..7d5ebdb31 100644
--- a/os/ports/RC/STM8/chtypes.h
+++ b/os/ports/RC/STM8/chtypes.h
@@ -47,55 +47,17 @@ typedef uint8_t         uint_fast8_t;   /**< C99-style 8 bits unsigned.     */
 typedef uint16_t        uint_fast16_t;  /**< C99-style 16 bits unsigned.    */
 typedef uint32_t        uint_fast32_t;  /**< C99-style 32 bits unsigned.    */
 
-/**
- * @brief   Boolean, recommended the fastest signed.
- */
-typedef int8_t          bool_t;
-
-/**
- * @brief   Thread mode flags, uint8_t is ok.
- */
-typedef uint8_t         tmode_t;
-
-/**
- * @brief   Thread state, uint8_t is ok.
- */
-typedef uint8_t         tstate_t;
-
-/**
- * @brief   Thread references counter, uint8_t is ok.
- */
-typedef uint8_t         trefs_t;
-
-/**
- * @brief   Priority, use the fastest unsigned type.
- */
-typedef uint8_t         tprio_t;
-
-/**
- * @brief   Message, use signed pointer equivalent.
- */
-typedef int16_t         msg_t;
-
-/**
- * @brief   Event Id, use fastest signed.
- */
-typedef int8_t          eventid_t;
-
-/**
- * @brief   Event Mask, recommended fastest unsigned.
- */
-typedef uint8_t         eventmask_t;
-
-/**
- * @brief   System Time, recommended fastest unsigned.
- */
-typedef uint16_t        systime_t;
-
-/**
- * @brief   Counter, recommended fastest signed.
- */
-typedef int8_t          cnt_t;
+typedef int8_t          bool_t;         /**< Fast boolean type.             */
+typedef uint8_t         tmode_t;        /**< Thread flags.                  */
+typedef uint8_t         tstate_t;       /**< Thread state.                  */
+typedef uint8_t         trefs_t;        /**< Thread references counter.     */
+typedef uint8_t         tslices_t;      /**< Thread time slices counter.    */
+typedef uint8_t         tprio_t;        /**< Thread priority.               */
+typedef int16_t         msg_t;          /**< Inter-thread message.          */
+typedef int8_t          eventid_t;      /**< Event Id.                      */
+typedef uint8_t         eventmask_t;    /**< Events mask.                   */
+typedef uint16_t        systime_t;      /**< System time.                   */
+typedef int8_t          cnt_t;          /**< Resources counter.             */
 
 /**
  * @brief   Inline function modifier.
diff --git a/os/ports/RVCT/ARMCMx/chtypes.h b/os/ports/RVCT/ARMCMx/chtypes.h
index 41f37c6f4..b9baf2502 100644
--- a/os/ports/RVCT/ARMCMx/chtypes.h
+++ b/os/ports/RVCT/ARMCMx/chtypes.h
@@ -40,6 +40,7 @@ typedef int32_t         bool_t;         /**< Fast boolean type.             */
 typedef uint8_t         tmode_t;        /**< Thread flags.                  */
 typedef uint8_t         tstate_t;       /**< Thread state.                  */
 typedef uint8_t         trefs_t;        /**< Thread references counter.     */
+typedef uint8_t         tslices_t;      /**< Thread time slices counter.    */
 typedef uint32_t        tprio_t;        /**< Thread priority.               */
 typedef int32_t         msg_t;          /**< Inter-thread message.          */
 typedef int32_t         eventid_t;      /**< Event Id.                      */
diff --git a/os/ports/cosmic/STM8/chtypes.h b/os/ports/cosmic/STM8/chtypes.h
index c957863d4..9c1749a96 100644
--- a/os/ports/cosmic/STM8/chtypes.h
+++ b/os/ports/cosmic/STM8/chtypes.h
@@ -47,55 +47,17 @@ typedef uint8_t         uint_fast8_t;   /**< C99-style 8 bits unsigned.     */
 typedef uint16_t        uint_fast16_t;  /**< C99-style 16 bits unsigned.    */
 typedef uint32_t        uint_fast32_t;  /**< C99-style 32 bits unsigned.    */
 
-/**
- * @brief   Boolean, recommended the fastest signed.
- */
-typedef int8_t          bool_t;
-
-/**
- * @brief   Thread mode flags, uint8_t is ok.
- */
-typedef uint8_t         tmode_t;
-
-/**
- * @brief   Thread state, uint8_t is ok.
- */
-typedef uint8_t         tstate_t;
-
-/**
- * @brief   Thread references counter, uint8_t is ok.
- */
-typedef uint8_t         trefs_t;
-
-/**
- * @brief   Priority, use the fastest unsigned type.
- */
-typedef uint8_t         tprio_t;
-
-/**
- * @brief   Message, use signed pointer equivalent.
- */
-typedef int16_t         msg_t;
-
-/**
- * @brief   Event Id, use fastest signed.
- */
-typedef int8_t          eventid_t;
-
-/**
- * @brief   Event Mask, recommended fastest unsigned.
- */
-typedef uint8_t         eventmask_t;
-
-/**
- * @brief   System Time, recommended fastest unsigned.
- */
-typedef uint16_t        systime_t;
-
-/**
- * @brief   Counter, recommended fastest signed.
- */
-typedef int8_t          cnt_t;
+typedef int8_t          bool_t;         /**< Fast boolean type.             */
+typedef uint8_t         tmode_t;        /**< Thread flags.                  */
+typedef uint8_t         tstate_t;       /**< Thread state.                  */
+typedef uint8_t         trefs_t;        /**< Thread references counter.     */
+typedef uint8_t         tslices_t;      /**< Thread time slices counter.    */
+typedef uint8_t         tprio_t;        /**< Thread priority.               */
+typedef int16_t         msg_t;          /**< Inter-thread message.          */
+typedef int8_t          eventid_t;      /**< Event Id.                      */
+typedef uint8_t         eventmask_t;    /**< Events mask.                   */
+typedef uint16_t        systime_t;      /**< System time.                   */
+typedef int8_t          cnt_t;          /**< Resources counter.             */
 
 /**
  * @brief   Inline function modifier.
diff --git a/readme.txt b/readme.txt
index eccfa8b92..e881c767e 100644
--- a/readme.txt
+++ b/readme.txt
@@ -82,6 +82,10 @@
 - NEW: Updated debug plugin 1.0.8 (backported to 2.4.0).
 - NEW: Added more accurate UBRR calculation in AVR serial driver (backported
   to 2.4.0).
+- NEW: Revision of the round-robin scheduling, now threads do not lose their
+  time slice when preempted. Each thread has its own time slices counter.
+  TODO: Half done, extend it to all ports.
+  TODO: Seek optimizations.
 
 *** 2.3.5 ***
 - FIX: Fixed RTC compile problem on STM32F103 (bug 3468445).