sys: xtimer concurrency/robustness improvement

boards/common/esp8266/include/board_common.h

@@ -73,8 +73,6 @@ extern "C" {
  * @name    XTimer configuration
  * @{
  */
-#define XTIMER_OVERHEAD             (0U)
-
 #if defined(MODULE_ESP_SW_TIMER)
 #define XTIMER_BACKOFF              (100U)
 #define XTIMER_ISR_BACKOFF          (100U)

boards/common/iotlab/include/board_common.h

@@ -50,7 +50,6 @@ extern "C" {
  * @{
  */
 #define XTIMER_WIDTH        (16U)
-#define XTIMER_OVERHEAD     (6U)
 /** @} */
 
 /**

boards/common/nucleo/include/board_nucleo.h

@@ -37,23 +37,17 @@ extern "C" {
 #define XTIMER_WIDTH                (16)
 #endif
 
-#if defined(CPU_MODEL_STM32F334R8)
-#define XTIMER_OVERHEAD             (5)
-#endif
-
 #if defined(CPU_FAM_STM32F1)
 #define XTIMER_WIDTH                (16)
 #define XTIMER_BACKOFF              (19)
 #endif
 
 #if defined(CPU_FAM_STM32L1)
 #define XTIMER_BACKOFF              (11)
-#define XTIMER_OVERHEAD             (6)
 #endif
 
 #if defined(CPU_FAM_STM32F4) || defined(CPU_MODEL_STM32F303ZE)
 #define XTIMER_BACKOFF              (8)
-#define XTIMER_OVERHEAD             (6)
 #endif
 /** @} */
 

boards/frdm-kw41z/include/board.h

@@ -85,7 +85,6 @@ extern "C"
 #define XTIMER_WIDTH                (16)
 #define XTIMER_BACKOFF              (5)
 #define XTIMER_ISR_BACKOFF          (5)
-#define XTIMER_OVERHEAD             (4)
 #define XTIMER_HZ                   (32768ul)
 #endif
 /** @} */

boards/hamilton/include/board.h

@@ -36,7 +36,6 @@ extern "C" {
  */
 #define XTIMER_DEV          TIMER_DEV(1)
 #define XTIMER_CHAN         (0)
-#define XTIMER_OVERHEAD     (0)
 /** @} */
 
 /**

boards/msba2/include/board.h

@@ -45,13 +45,6 @@ extern "C" {
 #define LED1_TOGGLE         (FIO3PIN ^= LED1_MASK)
 /** @} */
 
-/**
- * @name    xtimer tuning values
- * @{
- */
-#define XTIMER_OVERHEAD     7
-/** @} */
-
 #ifdef __cplusplus
 }
 #endif

boards/mulle/include/board.h

@@ -49,15 +49,13 @@
 #define XTIMER_WIDTH                (16)
 #define XTIMER_BACKOFF              (4)
 #define XTIMER_ISR_BACKOFF          (4)
-#define XTIMER_OVERHEAD             (3)
 #define XTIMER_HZ                   (32768ul)
 #else
 /* PIT xtimer configuration */
 #define XTIMER_DEV                  (TIMER_PIT_DEV(0))
 #define XTIMER_CHAN                 (0)
 #define XTIMER_BACKOFF              (40)
 #define XTIMER_ISR_BACKOFF          (40)
-#define XTIMER_OVERHEAD             (30)
 #endif
 /** @} */
 

boards/phynode-kw41z/include/board.h

@@ -100,7 +100,6 @@ extern "C"
 #define XTIMER_WIDTH                (16)
 #define XTIMER_BACKOFF              (5)
 #define XTIMER_ISR_BACKOFF          (5)
-#define XTIMER_OVERHEAD             (4)
 #define XTIMER_HZ                   (32768ul)
 #endif
 /** @} */

boards/stm32f4discovery/include/board.h

@@ -31,7 +31,6 @@ extern "C" {
  * @name xtimer configuration
  * @{
  */
-#define XTIMER_OVERHEAD     (6)
 #define XTIMER_BACKOFF      (10)
 /** @} */
 

boards/teensy31/include/board.h

@@ -43,7 +43,6 @@ extern "C" {
 #define XTIMER_CHAN                 (0)
 #define XTIMER_BACKOFF              (40)
 #define XTIMER_ISR_BACKOFF          (40)
-#define XTIMER_OVERHEAD             (30)
 /** @} */
 
 /**

boards/usb-kw41z/include/board.h

@@ -96,7 +96,6 @@ extern "C"
 #define XTIMER_WIDTH                (16)
 #define XTIMER_BACKOFF              (5)
 #define XTIMER_ISR_BACKOFF          (5)
-#define XTIMER_OVERHEAD             (4)
 #define XTIMER_HZ                   (32768ul)
 #endif
 /** @} */

cpu/esp32/esp_xtimer.c

@@ -148,7 +148,7 @@ void ets_timer_arm_us(ETSTimer *timer, uint32_t tmout, bool repeat)
 
     xtimer_set(&e2xt->xtimer, tmout);
 
-    e2xt->ets_timer->timer_expire = e2xt->xtimer.target;
+    e2xt->ets_timer->timer_expire = e2xt->xtimer.start_time + e2xt->xtimer.offset;
     e2xt->ets_timer->timer_period = repeat ? tmout : 0;
 }
 

cpu/native/include/periph_conf.h

@@ -44,8 +44,6 @@ extern "C" {
 /**
  * @brief xtimer configuration
  */
-#define XTIMER_OVERHEAD 14
-
 /* timer_set_absolute() has a high margin for possible underflow if set with
  * value not far in the future. To prevent this, we set high backoff values
  * here.

drivers/dose/dose.c

@@ -534,7 +534,7 @@ static const netdev_driver_t netdev_driver_dose = {
 
 void dose_setup(dose_t *ctx, const dose_params_t *params)
 {
-    static const xtimer_ticks32_t min_timeout = {.ticks32 = XTIMER_BACKOFF + XTIMER_OVERHEAD};
+    static const xtimer_ticks32_t min_timeout = {.ticks32 = XTIMER_BACKOFF};
 
     ctx->netdev.driver = &netdev_driver_dose;
 

pkg/ndn-riot/patches/0001-update-xtimer_member_names.patch

@@ -0,0 +1,52 @@
+From 22f5984e32bec116e3449ebad1b29b2a18f4d93e Mon Sep 17 00:00:00 2001
+From: Michel Rottleuthner <michel.rottleuthner@haw-hamburg.de>
+Date: Thu, 9 Jan 2020 11:16:38 +0100
+Subject: [PATCH] update xtimer_t member names
+
+---
+ app.c | 2 +-
+ l2.c  | 2 +-
+ pit.c | 2 +-
+ 3 files changed, 3 insertions(+), 3 deletions(-)
+
+diff --git a/app.c b/app.c
+index 8d37bd9..da9fc3c 100644
+--- a/app.c
++++ b/app.c
+@@ -380,7 +380,7 @@ int ndn_app_schedule(ndn_app_t* handle, ndn_app_sched_cb_t cb, void* context,
+     if (entry == NULL) return -1;
+
+     // initialize the timer
+-    entry->timer.target = entry->timer.long_target = 0;
++    entry->timer.offset = entry->timer.long_offset = 0;
+
+     // initialize the msg struct
+     entry->timer_msg.type = MSG_XTIMER;
+diff --git a/l2.c b/l2.c
+index 77d6be4..b64b9df 100644
+--- a/l2.c
++++ b/l2.c
+@@ -155,7 +155,7 @@ ndn_shared_block_t* ndn_l2_frag_receive(kernel_pid_t iface,
+         entry->id = id;
+
+         // initialize timer
+-        entry->timer.target = entry->timer.long_target = 0;
++        entry->timer.offset = entry->timer.long_offset = 0;
+         entry->timer_msg.type = NDN_L2_FRAG_MSG_TYPE_TIMEOUT;
+         entry->timer_msg.content.ptr = (char*)(&entry->timer_msg);
+
+diff --git a/pit.c b/pit.c
+index 644cf08..944a07c 100644
+--- a/pit.c
++++ b/pit.c
+@@ -155,7 +155,7 @@ int ndn_pit_add(kernel_pid_t face_id, int face_type, ndn_shared_block_t* si,
+ 	*pit_entry = entry;
+
+     /* initialize the timer */
+-    entry->timer.target = entry->timer.long_target = 0;
++    entry->timer.offset = entry->timer.long_offset = 0;
+
+     /* initialize the msg struct */
+     entry->timer_msg.type = NDN_PIT_MSG_TYPE_TIMEOUT;
+-- 
+2.24.1

pkg/nimble/patches/0001-xtimer_member_names.patch

@@ -0,0 +1,24 @@
+From 6b1223df6884bcfd00f4ecc8918b790baf041021 Mon Sep 17 00:00:00 2001
+From: Michel Rottleuthner <michel.rottleuthner@haw-hamburg.de>
+Date: Wed, 8 Jan 2020 19:50:48 +0100
+Subject: [PATCH] update xtimer_t member names
+
+---
+ porting/npl/riot/include/nimble/nimble_npl_os.h | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/porting/npl/riot/include/nimble/nimble_npl_os.h b/porting/npl/riot/include/nimble/nimble_npl_os.h
+index 67eb74e1..61c1ea8a 100644
+--- a/porting/npl/riot/include/nimble/nimble_npl_os.h
++++ b/porting/npl/riot/include/nimble/nimble_npl_os.h
+@@ -209,7 +209,7 @@ ble_npl_callout_stop(struct ble_npl_callout *co)
+ static inline bool
+ ble_npl_callout_is_active(struct ble_npl_callout *c)
+ {
+-    return (c->timer.target || c->timer.long_target);
++    return (c->timer.offset || c->timer.long_offset);
+ }
+
+ static inline ble_npl_time_t
+--
+2.24.1

pkg/semtech-loramac/contrib/semtech_loramac_timer.c

@@ -27,7 +27,10 @@ extern kernel_pid_t semtech_loramac_pid;
 
 void TimerInit(TimerEvent_t *obj, void (*cb)(void))
 {
-    obj->dev.target = 0;
+    obj->dev.start_time = 0;
+    obj->dev.long_start_time = 0;
+    obj->dev.offset = 0;
+    obj->dev.long_offset = 0;
     obj->running = 0;
     obj->cb = cb;
 }

sys/evtimer/evtimer.c

@@ -115,8 +115,10 @@ static void _update_timer(evtimer_t *evtimer)
 static uint32_t _get_offset(xtimer_t *timer)
 {
     uint64_t now_us = xtimer_now_usec64();
-    uint64_t target_us = _xtimer_usec_from_ticks64(
-                        ((uint64_t)timer->long_target) << 32 | timer->target);
+    uint64_t start_us = _xtimer_usec_from_ticks64(
+                        ((uint64_t)timer->long_start_time << 32) | timer->start_time);
+    uint64_t target_us = start_us + _xtimer_usec_from_ticks64(
+                        ((uint64_t)timer->long_offset) << 32 | timer->offset);
 
     if (target_us <= now_us) {
         return 0;

sys/include/xtimer.h

@@ -73,8 +73,10 @@ typedef void (*xtimer_callback_t)(void*);
  */
 typedef struct xtimer {
     struct xtimer *next;         /**< reference to next timer in timer lists */
-    uint32_t target;             /**< lower 32bit absolute target time */
-    uint32_t long_target;        /**< upper 32bit absolute target time */
+    uint32_t offset;             /**< lower 32bit offset time */
+    uint32_t long_offset;        /**< upper 32bit offset time */
+    uint32_t start_time;         /**< lower 32bit absolute start time */
+    uint32_t long_start_time;    /**< upper 32bit absolute start time */
     xtimer_callback_t callback;  /**< callback function to call when timer
                                      expires */
     void *arg;                   /**< argument to pass to callback function */
@@ -218,8 +220,6 @@ static inline void xtimer_periodic_wakeup(xtimer_ticks32_t *last_wakeup, uint32_
  * expired.
  *
  * @param[in] timer         timer struct to work with.
- *                          Its xtimer_t::target and xtimer_t::long_target
- *                          fields need to be initialized with 0 on first use
  * @param[in] offset        microseconds from now
  * @param[in] pid           pid of the thread that will be woken up
  */
@@ -232,8 +232,6 @@ static inline void xtimer_set_wakeup(xtimer_t *timer, uint32_t offset, kernel_pi
  * expired.
  *
  * @param[in] timer         timer struct to work with.
- *                          Its xtimer_t::target and xtimer_t::long_target
- *                          fields need to be initialized with 0 on first use
  * @param[in] offset        microseconds from now
  * @param[in] pid           pid of the thread that will be woken up
  */
@@ -252,8 +250,6 @@ static inline void xtimer_set_wakeup64(xtimer_t *timer, uint64_t offset, kernel_
  * know *exactly* what that means.
  *
  * @param[in] timer     the timer structure to use.
- *                      Its xtimer_t::target and xtimer_t::long_target
- *                      fields need to be initialized with 0 on first use
  * @param[in] offset    time in microseconds from now specifying that timer's
  *                      callback's execution time
  */
@@ -273,8 +269,6 @@ static inline void xtimer_set(xtimer_t *timer, uint32_t offset);
  * know *exactly* what that means.
  *
  * @param[in] timer       the timer structure to use.
- *                        Its xtimer_t::target and xtimer_t::long_target
- *                        fields need to be initialized with 0 on first use
  * @param[in] offset_us   time in microseconds from now specifying that timer's
  *                        callback's execution time
  */
@@ -426,8 +420,6 @@ void xtimer_set_timeout_flag(xtimer_t *t, uint32_t timeout);
  * needs to point to valid memory until the message has been delivered.
  *
  * @param[in] timer         timer struct to work with.
- *                          Its xtimer_t::target and xtimer_t::long_target
- *                          fields need to be initialized with 0 on first use.
  * @param[in] offset        microseconds from now
  * @param[in] msg           ptr to msg that will be sent
  * @param[in] target_pid    pid the message will be sent to
@@ -444,8 +436,6 @@ static inline void xtimer_set_msg(xtimer_t *timer, uint32_t offset, msg_t *msg,
  * needs to point to valid memory until the message has been delivered.
  *
  * @param[in] timer         timer struct to work with.
- *                          Its xtimer_t::target and xtimer_t::long_target
- *                          fields need to be initialized with 0 on first use.
  * @param[in] offset        microseconds from now
  * @param[in] msg           ptr to msg that will be sent
  * @param[in] target_pid    pid the message will be sent to
@@ -487,29 +477,6 @@ static inline int xtimer_msg_receive_timeout64(msg_t *msg, uint64_t timeout);
 #define XTIMER_BACKOFF 30
 #endif
 
-/**
- * @brief xtimer overhead value, in hardware ticks
- *
- * This value specifies the time a timer will be late if uncorrected, e.g.,
- * the system-specific xtimer execution time from timer ISR to executing
- * a timer's callback's first instruction.
- *
- * E.g., with XTIMER_OVERHEAD == 0
- * start=xtimer_now();
- * xtimer_set(&timer, X);
- * (in callback:)
- * overhead=xtimer_now()-start-X;
- *
- * xtimer automatically subtracts XTIMER_OVERHEAD from a timer's target time,
- * but when the timer triggers, xtimer will spin-lock until a timer's target
- * time is reached, so timers will never trigger early.
- *
- * This is supposed to be defined per-device in e.g., periph_conf.h.
- */
-#ifndef XTIMER_OVERHEAD
-#define XTIMER_OVERHEAD 20
-#endif
-
 #ifndef XTIMER_ISR_BACKOFF
 /**
  * @brief   xtimer IRQ backoff time, in hardware ticks
@@ -522,29 +489,6 @@ static inline int xtimer_msg_receive_timeout64(msg_t *msg, uint64_t timeout);
 #define XTIMER_ISR_BACKOFF 20
 #endif
 
-#ifndef XTIMER_PERIODIC_SPIN
-/**
- * @brief   xtimer_periodic_wakeup spin cutoff
- *
- * If the difference between target time and now is less than this value, then
- * xtimer_periodic_wakeup will use xtimer_spin instead of setting a timer.
- */
-#define XTIMER_PERIODIC_SPIN (XTIMER_BACKOFF * 2)
-#endif
-
-#ifndef XTIMER_PERIODIC_RELATIVE
-/**
- * @brief   xtimer_periodic_wakeup relative target cutoff
- *
- * If the difference between target time and now is less than this value, then
- * xtimer_periodic_wakeup will set a relative target time in the future instead
- * of the true target.
- *
- * This is done to prevent target time underflows.
- */
-#define XTIMER_PERIODIC_RELATIVE (512)
-#endif
-
 /*
  * Default xtimer configuration
  */