From 882ec01e42227445a63f6d5b38cac14d8635f2ad Mon Sep 17 00:00:00 2001 From: Damien George Date: Tue, 31 Jan 2017 13:59:53 +1100 Subject: stmhal: Initial implementation of multithreading, currently disabled. This patch brings the _thread module to stmhal/pyboard. There is a very simple round-robin thread scheduler, which is disabled if there is only one thread (for efficiency when threading is not used). The scheduler currently switches threads at a rate of 250Hz using the systick timer and the pend-SV interrupt. The GIL is disabled so one must be careful to use lock objects to prevent concurrent access of objects. The threading is disabled by default, one can enabled it with the config option MICROPY_PY_THREAD to test it out. --- stmhal/pybthread.h | 62 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 62 insertions(+) create mode 100644 stmhal/pybthread.h (limited to 'stmhal/pybthread.h') diff --git a/stmhal/pybthread.h b/stmhal/pybthread.h new file mode 100644 index 000000000..d4310c66a --- /dev/null +++ b/stmhal/pybthread.h @@ -0,0 +1,62 @@ +/* + * This file is part of the MicroPython project, http://micropython.org/ + * + * The MIT License (MIT) + * + * Copyright (c) 2017 Damien P. George + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to deal + * in the Software without restriction, including without limitation the rights + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell + * copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN + * THE SOFTWARE. + */ + +#ifndef MICROPY_INCLUDED_STMHAL_PYBTHREAD_H +#define MICROPY_INCLUDED_STMHAL_PYBTHREAD_H + +typedef struct _pyb_thread_t { + void *sp; + uint32_t local_state; + void *arg; // thread Python args, a GC root pointer + void *stack; // pointer to the stack + size_t stack_len; // number of words in the stack + struct _pyb_thread_t *prev; + struct _pyb_thread_t *next; +} pyb_thread_t; + +extern int pyb_thread_enabled; +extern pyb_thread_t *pyb_thread_cur; + +void pyb_thread_init(pyb_thread_t *th); +uint32_t pyb_thread_new(pyb_thread_t *th, void *stack, size_t stack_len, void *entry, void *arg); + +static inline uint32_t pyb_thread_get_id(void) { + return (uint32_t)pyb_thread_cur; +} + +static inline void pyb_thread_set_local(void *value) { + pyb_thread_cur->local_state = (uint32_t)value; +} + +static inline void *pyb_thread_get_local(void) { + return (void*)pyb_thread_cur->local_state; +} + +static inline void pyb_thread_yield(void) { + SCB->ICSR = SCB_ICSR_PENDSVSET_Msk; +} + +#endif // MICROPY_INCLUDED_STMHAL_PYBTHREAD_H -- cgit v1.2.3 From 05a4859585c4e0a55fca2e7467ba70da6453fdcb Mon Sep 17 00:00:00 2001 From: Damien George Date: Mon, 6 Feb 2017 15:13:30 +1100 Subject: stmhal: Implement a proper thread scheduler. This patch changes the threading implementation from simple round-robin with busy waits on mutexs, to proper scheduling whereby threads that are waiting on a mutex are only scheduled when the mutex becomes available. --- stmhal/main.c | 4 ++ stmhal/modmachine.c | 5 ++ stmhal/mpconfigport.h | 14 ++++ stmhal/mpthreadport.c | 35 +--------- stmhal/mpthreadport.h | 14 +++- stmhal/pybthread.c | 179 +++++++++++++++++++++++++++++++++++++++++++------- stmhal/pybthread.h | 26 ++++++-- stmhal/stm32_it.c | 12 +++- stmhal/systick.c | 10 +++ 9 files changed, 236 insertions(+), 63 deletions(-) (limited to 'stmhal/pybthread.h') diff --git a/stmhal/main.c b/stmhal/main.c index 7bfdc52c3..bcc429df2 100644 --- a/stmhal/main.c +++ b/stmhal/main.c @@ -695,6 +695,10 @@ soft_reset_exit: can_deinit(); #endif + #if MICROPY_PY_THREAD + pyb_thread_deinit(); + #endif + first_soft_reset = false; goto soft_reset; } diff --git a/stmhal/modmachine.c b/stmhal/modmachine.c index 4a3fe1ec9..16c50079d 100644 --- a/stmhal/modmachine.c +++ b/stmhal/modmachine.c @@ -41,6 +41,7 @@ #include "extmod/vfs_fat.h" #include "gccollect.h" #include "irq.h" +#include "pybthread.h" #include "rng.h" #include "storage.h" #include "pin.h" @@ -159,6 +160,10 @@ STATIC mp_obj_t machine_info(mp_uint_t n_args, const mp_obj_t *args) { } } + #if MICROPY_PY_THREAD + pyb_thread_dump(); + #endif + if (n_args == 1) { // arg given means dump gc allocation table gc_dump_alloc_table(); diff --git a/stmhal/mpconfigport.h b/stmhal/mpconfigport.h index 5828f07c7..38a5ac5da 100644 --- a/stmhal/mpconfigport.h +++ b/stmhal/mpconfigport.h @@ -299,7 +299,21 @@ static inline mp_uint_t disable_irq(void) { #define MICROPY_BEGIN_ATOMIC_SECTION() disable_irq() #define MICROPY_END_ATOMIC_SECTION(state) enable_irq(state) + +#if MICROPY_PY_THREAD +#define MICROPY_EVENT_POLL_HOOK \ + do { \ + if (pyb_thread_enabled) { \ + MP_THREAD_GIL_EXIT(); \ + pyb_thread_yield(); \ + MP_THREAD_GIL_ENTER(); \ + } else { \ + __WFI(); \ + } \ + } while (0); +#else #define MICROPY_EVENT_POLL_HOOK __WFI(); +#endif // There is no classical C heap in bare-metal ports, only Python // garbage-collected heap. For completeness, emulate C heap via diff --git a/stmhal/mpthreadport.c b/stmhal/mpthreadport.c index 97c19647c..d7c5b569b 100644 --- a/stmhal/mpthreadport.c +++ b/stmhal/mpthreadport.c @@ -44,15 +44,13 @@ void mp_thread_init(void) { void mp_thread_gc_others(void) { mp_thread_mutex_lock(&thread_mutex, 1); - gc_collect_root((void**)&pyb_thread_cur, 1); - for (pyb_thread_t *th = pyb_thread_cur;; th = th->next) { + for (pyb_thread_t *th = pyb_thread_all; th != NULL; th = th->all_next) { + gc_collect_root((void**)&th, 1); gc_collect_root(&th->arg, 1); + gc_collect_root(&th->stack, 1); if (th != pyb_thread_cur) { gc_collect_root(th->stack, th->stack_len); } - if (th->next == pyb_thread_cur) { - break; - } } mp_thread_mutex_unlock(&thread_mutex); } @@ -93,31 +91,4 @@ void mp_thread_start(void) { void mp_thread_finish(void) { } -void mp_thread_mutex_init(mp_thread_mutex_t *mutex) { - *mutex = 0; -} - -int mp_thread_mutex_lock(mp_thread_mutex_t *mutex, int wait) { - uint32_t irq_state = disable_irq(); - if (*mutex) { - // mutex is locked - if (!wait) { - enable_irq(irq_state); - return 0; // failed to lock mutex - } - while (*mutex) { - enable_irq(irq_state); - pyb_thread_yield(); - irq_state = disable_irq(); - } - } - *mutex = 1; - enable_irq(irq_state); - return 1; // have mutex -} - -void mp_thread_mutex_unlock(mp_thread_mutex_t *mutex) { - *mutex = 0; -} - #endif // MICROPY_PY_THREAD diff --git a/stmhal/mpthreadport.h b/stmhal/mpthreadport.h index 4fef323eb..3d8b4ef01 100644 --- a/stmhal/mpthreadport.h +++ b/stmhal/mpthreadport.h @@ -29,7 +29,7 @@ #include "py/mpthread.h" #include "pybthread.h" -typedef uint32_t mp_thread_mutex_t; +typedef pyb_mutex_t mp_thread_mutex_t; void mp_thread_init(void); void mp_thread_gc_others(void); @@ -42,4 +42,16 @@ static inline struct _mp_state_thread_t *mp_thread_get_state(void) { return pyb_thread_get_local(); } +static inline void mp_thread_mutex_init(mp_thread_mutex_t *m) { + pyb_mutex_init(m); +} + +static inline int mp_thread_mutex_lock(mp_thread_mutex_t *m, int wait) { + return pyb_mutex_lock(m, wait); +} + +static inline void mp_thread_mutex_unlock(mp_thread_mutex_t *m) { + pyb_mutex_unlock(m); +} + #endif // __MICROPY_INCLUDED_STMHAL_MPTHREADPORT_H__ diff --git a/stmhal/pybthread.c b/stmhal/pybthread.c index 9f9f82a45..51e9a738d 100644 --- a/stmhal/pybthread.c +++ b/stmhal/pybthread.c @@ -34,29 +34,80 @@ #if MICROPY_PY_THREAD -int pyb_thread_enabled; -pyb_thread_t *pyb_thread_cur; +#define PYB_MUTEX_UNLOCKED ((void*)0) +#define PYB_MUTEX_LOCKED ((void*)1) + +extern void __fatal_error(const char*); + +volatile int pyb_thread_enabled; +pyb_thread_t *volatile pyb_thread_all; +pyb_thread_t *volatile pyb_thread_cur; + +static inline void pyb_thread_add_to_runable(pyb_thread_t *thread) { + thread->run_prev = pyb_thread_cur->run_prev; + thread->run_next = pyb_thread_cur; + pyb_thread_cur->run_prev->run_next = thread; + pyb_thread_cur->run_prev = thread; +} + +static inline void pyb_thread_remove_from_runable(pyb_thread_t *thread) { + if (thread->run_next == thread) { + __fatal_error("deadlock"); + } + thread->run_prev->run_next = thread->run_next; + thread->run_next->run_prev = thread->run_prev; +} void pyb_thread_init(pyb_thread_t *thread) { + pyb_thread_enabled = 0; + pyb_thread_all = thread; pyb_thread_cur = thread; - pyb_thread_cur->sp = NULL; // will be set when this thread switches out - pyb_thread_cur->local_state = 0; // will be set by mp_thread_init - pyb_thread_cur->arg = NULL; - pyb_thread_cur->stack = &_heap_end; - pyb_thread_cur->stack_len = ((uint32_t)&_estack - (uint32_t)&_heap_end) / sizeof(uint32_t); - pyb_thread_cur->prev = thread; - pyb_thread_cur->next = thread; + thread->sp = NULL; // will be set when this thread switches out + thread->local_state = 0; // will be set by mp_thread_init + thread->arg = NULL; + thread->stack = &_heap_end; + thread->stack_len = ((uint32_t)&_estack - (uint32_t)&_heap_end) / sizeof(uint32_t); + thread->all_next = NULL; + thread->run_prev = thread; + thread->run_next = thread; + thread->queue_next = NULL; +} + +void pyb_thread_deinit() { + uint32_t irq_state = disable_irq(); + pyb_thread_enabled = 0; + pyb_thread_all = pyb_thread_cur; + pyb_thread_cur->all_next = NULL; + pyb_thread_cur->run_prev = pyb_thread_cur; + pyb_thread_cur->run_next = pyb_thread_cur; + enable_irq(irq_state); } STATIC void pyb_thread_terminate(void) { - uint32_t irq_state = raise_irq_pri(IRQ_PRI_PENDSV); - pyb_thread_cur->prev->next = pyb_thread_cur->next; - pyb_thread_cur->next->prev = pyb_thread_cur->prev; - if (pyb_thread_cur->next == pyb_thread_cur->prev) { + uint32_t irq_state = disable_irq(); + pyb_thread_t *thread = pyb_thread_cur; + // take current thread off the run list + pyb_thread_remove_from_runable(thread); + // take current thread off the list of all threads + for (pyb_thread_t **n = (pyb_thread_t**)&pyb_thread_all;; n = &(*n)->all_next) { + if (*n == thread) { + *n = thread->all_next; + break; + } + } + // clean pointers as much as possible to help GC + thread->all_next = NULL; + thread->queue_next = NULL; + thread->stack = NULL; + if (pyb_thread_all->all_next == NULL) { + // only 1 thread left pyb_thread_enabled = 0; } - restore_irq_pri(irq_state); - pyb_thread_yield(); // should not return + // thread switch will occur after we enable irqs + SCB->ICSR = SCB_ICSR_PENDSVSET_Msk; + enable_irq(irq_state); + // should not return + __fatal_error("could not terminate"); } uint32_t pyb_thread_new(pyb_thread_t *thread, void *stack, size_t stack_len, void *entry, void *arg) { @@ -77,21 +128,105 @@ uint32_t pyb_thread_new(pyb_thread_t *thread, void *stack, size_t stack_len, voi thread->arg = arg; thread->stack = stack; thread->stack_len = stack_len; - uint32_t irq_state = raise_irq_pri(IRQ_PRI_PENDSV); + thread->queue_next = NULL; + uint32_t irq_state = disable_irq(); pyb_thread_enabled = 1; - thread->next = pyb_thread_cur->next; - thread->prev = pyb_thread_cur; - pyb_thread_cur->next->prev = thread; - pyb_thread_cur->next = thread; - restore_irq_pri(irq_state); + thread->all_next = pyb_thread_all; + pyb_thread_all = thread; + pyb_thread_add_to_runable(thread); + enable_irq(irq_state); return (uint32_t)thread; // success } +void pyb_thread_dump(void) { + if (!pyb_thread_enabled) { + printf("THREAD: only main thread\n"); + } else { + printf("THREAD:\n"); + for (pyb_thread_t *th = pyb_thread_all; th != NULL; th = th->all_next) { + bool runable = false; + for (pyb_thread_t *th2 = pyb_thread_cur;; th2 = th2->run_next) { + if (th == th2) { + runable = true; + break; + } + if (th2->run_next == pyb_thread_cur) { + break; + } + } + printf(" id=%p sp=%p sz=%u", th, th->stack, th->stack_len); + if (runable) { + printf(" (runable)"); + } + printf("\n"); + } + } +} + // should only be called from pendsv_isr_handler void *pyb_thread_next(void *sp) { pyb_thread_cur->sp = sp; - pyb_thread_cur = pyb_thread_cur->next; + pyb_thread_cur = pyb_thread_cur->run_next; + pyb_thread_cur->timeslice = 4; // in milliseconds return pyb_thread_cur->sp; } +void pyb_mutex_init(pyb_mutex_t *m) { + *m = PYB_MUTEX_UNLOCKED; +} + +int pyb_mutex_lock(pyb_mutex_t *m, int wait) { + uint32_t irq_state = disable_irq(); + if (*m == PYB_MUTEX_UNLOCKED) { + // mutex is available + *m = PYB_MUTEX_LOCKED; + enable_irq(irq_state); + } else { + // mutex is locked + if (!wait) { + enable_irq(irq_state); + return 0; // failed to lock mutex + } + if (*m == PYB_MUTEX_LOCKED) { + *m = pyb_thread_cur; + } else { + for (pyb_thread_t *n = *m;; n = n->queue_next) { + if (n->queue_next == NULL) { + n->queue_next = pyb_thread_cur; + break; + } + } + } + pyb_thread_cur->queue_next = NULL; + // take current thread off the run list + pyb_thread_remove_from_runable(pyb_thread_cur); + // thread switch will occur after we enable irqs + SCB->ICSR = SCB_ICSR_PENDSVSET_Msk; + enable_irq(irq_state); + // when we come back we have the mutex + } + return 1; // have mutex +} + +void pyb_mutex_unlock(pyb_mutex_t *m) { + uint32_t irq_state = disable_irq(); + if (*m == PYB_MUTEX_LOCKED) { + // no threads are blocked on the mutex + *m = PYB_MUTEX_UNLOCKED; + } else { + // at least one thread is blocked on this mutex + pyb_thread_t *th = *m; + if (th->queue_next == NULL) { + // no other threads are blocked + *m = PYB_MUTEX_LOCKED; + } else { + // at least one other thread is still blocked + *m = th->queue_next; + } + // put unblocked thread on runable list + pyb_thread_add_to_runable(th); + } + enable_irq(irq_state); +} + #endif // MICROPY_PY_THREAD diff --git a/stmhal/pybthread.h b/stmhal/pybthread.h index d4310c66a..6edb2400e 100644 --- a/stmhal/pybthread.h +++ b/stmhal/pybthread.h @@ -33,15 +33,23 @@ typedef struct _pyb_thread_t { void *arg; // thread Python args, a GC root pointer void *stack; // pointer to the stack size_t stack_len; // number of words in the stack - struct _pyb_thread_t *prev; - struct _pyb_thread_t *next; + uint32_t timeslice; + struct _pyb_thread_t *all_next; + struct _pyb_thread_t *run_prev; + struct _pyb_thread_t *run_next; + struct _pyb_thread_t *queue_next; } pyb_thread_t; -extern int pyb_thread_enabled; -extern pyb_thread_t *pyb_thread_cur; +typedef pyb_thread_t *pyb_mutex_t; + +extern volatile int pyb_thread_enabled; +extern pyb_thread_t *volatile pyb_thread_all; +extern pyb_thread_t *volatile pyb_thread_cur; void pyb_thread_init(pyb_thread_t *th); +void pyb_thread_deinit(); uint32_t pyb_thread_new(pyb_thread_t *th, void *stack, size_t stack_len, void *entry, void *arg); +void pyb_thread_dump(void); static inline uint32_t pyb_thread_get_id(void) { return (uint32_t)pyb_thread_cur; @@ -56,7 +64,15 @@ static inline void *pyb_thread_get_local(void) { } static inline void pyb_thread_yield(void) { - SCB->ICSR = SCB_ICSR_PENDSVSET_Msk; + if (pyb_thread_cur->run_next == pyb_thread_cur) { + __WFI(); + } else { + SCB->ICSR = SCB_ICSR_PENDSVSET_Msk; + } } +void pyb_mutex_init(pyb_mutex_t *m); +int pyb_mutex_lock(pyb_mutex_t *m, int wait); +void pyb_mutex_unlock(pyb_mutex_t *m); + #endif // MICROPY_INCLUDED_STMHAL_PYBTHREAD_H diff --git a/stmhal/stm32_it.c b/stmhal/stm32_it.c index 4152050a9..d8fcc59ce 100644 --- a/stmhal/stm32_it.c +++ b/stmhal/stm32_it.c @@ -70,6 +70,7 @@ #include "stm32_it.h" #include STM32_HAL_H +#include "py/mpstate.h" #include "py/obj.h" #include "py/mphal.h" #include "pendsv.h" @@ -315,9 +316,14 @@ void SysTick_Handler(void) { } #if MICROPY_PY_THREAD - // signal a thread switch at 4ms=250Hz - if (pyb_thread_enabled && (uwTick & 0x03) == 0x03) { - SCB->ICSR = SCB_ICSR_PENDSVSET_Msk; + if (pyb_thread_enabled) { + if (pyb_thread_cur->timeslice == 0) { + if (pyb_thread_cur->run_next != pyb_thread_cur) { + SCB->ICSR = SCB_ICSR_PENDSVSET_Msk; + } + } else { + --pyb_thread_cur->timeslice; + } } #endif } diff --git a/stmhal/systick.c b/stmhal/systick.c index aed5b9690..ade05d74d 100644 --- a/stmhal/systick.c +++ b/stmhal/systick.c @@ -29,9 +29,11 @@ #include "py/obj.h" #include "irq.h" #include "systick.h" +#include "pybthread.h" // We provide our own version of HAL_Delay that calls __WFI while waiting, in // order to reduce power consumption. +// Note: Upon entering this function we may or may not have the GIL. void HAL_Delay(uint32_t Delay) { if (query_irq() == IRQ_STATE_ENABLED) { // IRQs enabled, so can use systick counter to do the delay @@ -40,7 +42,15 @@ void HAL_Delay(uint32_t Delay) { // Wraparound of tick is taken care of by 2's complement arithmetic. while (uwTick - start < Delay) { // Enter sleep mode, waiting for (at least) the SysTick interrupt. + #if MICROPY_PY_THREAD + if (pyb_thread_enabled) { + pyb_thread_yield(); + } else { + __WFI(); + } + #else __WFI(); + #endif } } else { // IRQs disabled, so need to use a busy loop for the delay. -- cgit v1.2.3