rockbox/firmware/export/thread.h
Frank Gevaerts 376d8d577f Add IO priority handling. Currently all IO has equal priority, except the dircache scanning thread which is lower. This fixes the slow boot problem for me, with the added benefit that actual audio playback also starts faster.
Lots of the changes are due to changing storage_(read|write)sectors() from macros to wrapper functions. This means that they have to be called with IF_MD2(drive,) again.

Flyspray: FS#11167
Author: Frank Gevaerts


git-svn-id: svn://svn.rockbox.org/rockbox/trunk@25459 a1c6a512-1295-4272-9138-f99709370657
2010-04-03 22:02:09 +00:00

568 lines
20 KiB
C

/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2002 by Ulf Ralberg
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#ifndef THREAD_H
#define THREAD_H
#include "config.h"
#include <inttypes.h>
#include <stddef.h>
#include <stdbool.h>
/* Priority scheduling (when enabled with HAVE_PRIORITY_SCHEDULING) works
* by giving high priority threads more CPU time than lower priority threads
* when they need it. Priority is differential such that the priority
* difference between a lower priority runnable thread and the highest priority
* runnable thread determines the amount of aging necessary for the lower
* priority thread to be scheduled in order to prevent starvation.
*
* If software playback codec pcm buffer is going down to critical, codec
* can gradually raise its own priority to override user interface and
* prevent playback skipping.
*/
#define PRIORITY_RESERVED_HIGH 0 /* Reserved */
#define PRIORITY_RESERVED_LOW 32 /* Reserved */
#define HIGHEST_PRIORITY 1 /* The highest possible thread priority */
#define LOWEST_PRIORITY 31 /* The lowest possible thread priority */
/* Realtime range reserved for threads that will not allow threads of lower
* priority to age and run (future expansion) */
#define PRIORITY_REALTIME_1 1
#define PRIORITY_REALTIME_2 2
#define PRIORITY_REALTIME_3 3
#define PRIORITY_REALTIME_4 4
#define PRIORITY_REALTIME 4 /* Lowest realtime range */
#define PRIORITY_BUFFERING 15 /* Codec buffering thread */
#define PRIORITY_USER_INTERFACE 16 /* The main thread */
#define PRIORITY_RECORDING 16 /* Recording thread */
#define PRIORITY_PLAYBACK 16 /* Variable between this and MAX */
#define PRIORITY_PLAYBACK_MAX 5 /* Maximum allowable playback priority */
#define PRIORITY_SYSTEM 18 /* All other firmware threads */
#define PRIORITY_BACKGROUND 20 /* Normal application threads */
#define NUM_PRIORITIES 32
#define PRIORITY_IDLE 32 /* Priority representative of no tasks */
#define IO_PRIORITY_IMMEDIATE 0
#define IO_PRIORITY_BACKGROUND 32
#if CONFIG_CODEC == SWCODEC
#ifdef HAVE_RECORDING
#define BASETHREADS 17
#else
#define BASETHREADS 16
#endif
#else
#define BASETHREADS 11
#endif /* CONFIG_CODE == * */
#ifndef TARGET_EXTRA_THREADS
#define TARGET_EXTRA_THREADS 0
#endif
#define MAXTHREADS (BASETHREADS+TARGET_EXTRA_THREADS)
#define DEFAULT_STACK_SIZE 0x400 /* Bytes */
#ifndef SIMULATOR
/* Need to keep structures inside the header file because debug_menu
* needs them. */
#ifdef CPU_COLDFIRE
struct regs
{
uint32_t macsr; /* 0 - EMAC status register */
uint32_t d[6]; /* 4-24 - d2-d7 */
uint32_t a[5]; /* 28-44 - a2-a6 */
uint32_t sp; /* 48 - Stack pointer (a7) */
uint32_t start; /* 52 - Thread start address, or NULL when started */
};
#elif CONFIG_CPU == SH7034
struct regs
{
uint32_t r[7]; /* 0-24 - Registers r8 thru r14 */
uint32_t sp; /* 28 - Stack pointer (r15) */
uint32_t pr; /* 32 - Procedure register */
uint32_t start; /* 36 - Thread start address, or NULL when started */
};
#elif defined(CPU_ARM)
struct regs
{
uint32_t r[8]; /* 0-28 - Registers r4-r11 */
uint32_t sp; /* 32 - Stack pointer (r13) */
uint32_t lr; /* 36 - r14 (lr) */
uint32_t start; /* 40 - Thread start address, or NULL when started */
};
#elif defined(CPU_MIPS)
struct regs
{
uint32_t r[9]; /* 0-32 - Registers s0-s7, fp */
uint32_t sp; /* 36 - Stack pointer */
uint32_t ra; /* 40 - Return address */
uint32_t start; /* 44 - Thread start address, or NULL when started */
};
#endif /* CONFIG_CPU */
#else
struct regs
{
void *t; /* Simulator OS thread */
void *s; /* Semaphore for blocking and wakeup */
void (*start)(void); /* Start function */
};
#endif /* !SIMULATOR */
/* NOTE: The use of the word "queue" may also refer to a linked list of
threads being maintained that are normally dealt with in FIFO order
and not necessarily kernel event_queue */
enum
{
/* States without a timeout must be first */
STATE_KILLED = 0, /* Thread is killed (default) */
STATE_RUNNING, /* Thread is currently running */
STATE_BLOCKED, /* Thread is indefinitely blocked on a queue */
/* These states involve adding the thread to the tmo list */
STATE_SLEEPING, /* Thread is sleeping with a timeout */
STATE_BLOCKED_W_TMO, /* Thread is blocked on a queue with a timeout */
/* Miscellaneous states */
STATE_FROZEN, /* Thread is suspended and will not run until
thread_thaw is called with its ID */
THREAD_NUM_STATES,
TIMEOUT_STATE_FIRST = STATE_SLEEPING,
};
#if NUM_CORES > 1
/* Pointer value for name field to indicate thread is being killed. Using
* an alternate STATE_* won't work since that would interfere with operation
* while the thread is still running. */
#define THREAD_DESTRUCT ((const char *)~(intptr_t)0)
#endif
/* Link information for lists thread is in */
struct thread_entry; /* forward */
struct thread_list
{
struct thread_entry *prev; /* Previous thread in a list */
struct thread_entry *next; /* Next thread in a list */
};
/* Small objects for core-wise mutual exclusion */
#if CONFIG_CORELOCK == SW_CORELOCK
/* No reliable atomic instruction available - use Peterson's algorithm */
struct corelock
{
volatile unsigned char myl[NUM_CORES];
volatile unsigned char turn;
} __attribute__((packed));
void corelock_init(struct corelock *cl);
void corelock_lock(struct corelock *cl);
int corelock_try_lock(struct corelock *cl);
void corelock_unlock(struct corelock *cl);
#elif CONFIG_CORELOCK == CORELOCK_SWAP
/* Use native atomic swap/exchange instruction */
struct corelock
{
volatile unsigned char locked;
} __attribute__((packed));
#define corelock_init(cl) \
({ (cl)->locked = 0; })
#define corelock_lock(cl) \
({ while (test_and_set(&(cl)->locked, 1)); })
#define corelock_try_lock(cl) \
({ test_and_set(&(cl)->locked, 1) ? 0 : 1; })
#define corelock_unlock(cl) \
({ (cl)->locked = 0; })
#else
/* No atomic corelock op needed or just none defined */
#define corelock_init(cl)
#define corelock_lock(cl)
#define corelock_try_lock(cl)
#define corelock_unlock(cl)
#endif /* core locking selection */
#ifdef HAVE_PRIORITY_SCHEDULING
struct blocker
{
struct thread_entry *thread; /* thread blocking other threads
(aka. object owner) */
int priority; /* highest priority waiter */
struct thread_entry * (*wakeup_protocol)(struct thread_entry *thread);
};
/* Choices of wakeup protocol */
/* For transfer of object ownership by one thread to another thread by
* the owning thread itself (mutexes) */
struct thread_entry *
wakeup_priority_protocol_transfer(struct thread_entry *thread);
/* For release by owner where ownership doesn't change - other threads,
* interrupts, timeouts, etc. (mutex timeout, queues) */
struct thread_entry *
wakeup_priority_protocol_release(struct thread_entry *thread);
struct priority_distribution
{
uint8_t hist[NUM_PRIORITIES]; /* Histogram: Frequency for each priority */
uint32_t mask; /* Bitmask of hist entries that are not zero */
};
#endif /* HAVE_PRIORITY_SCHEDULING */
/* Information kept in each thread slot
* members are arranged according to size - largest first - in order
* to ensure both alignment and packing at the same time.
*/
struct thread_entry
{
struct regs context; /* Register context at switch -
_must_ be first member */
uintptr_t *stack; /* Pointer to top of stack */
const char *name; /* Thread name */
long tmo_tick; /* Tick when thread should be woken from
timeout -
states: STATE_SLEEPING/STATE_BLOCKED_W_TMO */
struct thread_list l; /* Links for blocked/waking/running -
circular linkage in both directions */
struct thread_list tmo; /* Links for timeout list -
Circular in reverse direction, NULL-terminated in
forward direction -
states: STATE_SLEEPING/STATE_BLOCKED_W_TMO */
struct thread_entry **bqp; /* Pointer to list variable in kernel
object where thread is blocked - used
for implicit unblock and explicit wake
states: STATE_BLOCKED/STATE_BLOCKED_W_TMO */
#if NUM_CORES > 1
struct corelock *obj_cl; /* Object corelock where thead is blocked -
states: STATE_BLOCKED/STATE_BLOCKED_W_TMO */
#endif
struct thread_entry *queue; /* List of threads waiting for thread to be
removed */
#ifdef HAVE_EXTENDED_MESSAGING_AND_NAME
#define HAVE_WAKEUP_EXT_CB
void (*wakeup_ext_cb)(struct thread_entry *thread); /* Callback that
performs special steps needed when being
forced off of an object's wait queue that
go beyond the standard wait queue removal
and priority disinheritance */
/* Only enabled when using queue_send for now */
#endif
#if defined(HAVE_EXTENDED_MESSAGING_AND_NAME) || NUM_CORES > 1
intptr_t retval; /* Return value from a blocked operation/
misc. use */
#endif
#ifdef HAVE_PRIORITY_SCHEDULING
/* Priority summary of owned objects that support inheritance */
struct blocker *blocker; /* Pointer to blocker when this thread is blocked
on an object that supports PIP -
states: STATE_BLOCKED/STATE_BLOCKED_W_TMO */
struct priority_distribution pdist; /* Priority summary of owned objects
that have blocked threads and thread's own
base priority */
int skip_count; /* Number of times skipped if higher priority
thread was running */
#endif
uint16_t id; /* Current slot id */
unsigned short stack_size; /* Size of stack in bytes */
#ifdef HAVE_PRIORITY_SCHEDULING
unsigned char base_priority; /* Base priority (set explicitly during
creation or thread_set_priority) */
unsigned char priority; /* Scheduled priority (higher of base or
all threads blocked by this one) */
#endif
unsigned char state; /* Thread slot state (STATE_*) */
#ifdef HAVE_SCHEDULER_BOOSTCTRL
unsigned char cpu_boost; /* CPU frequency boost flag */
#endif
#if NUM_CORES > 1
unsigned char core; /* The core to which thread belongs */
struct corelock waiter_cl; /* Corelock for thread_wait */
struct corelock slot_cl; /* Corelock to lock thread slot */
#endif
#ifdef HAVE_IO_PRIORITY
unsigned char io_priority;
#endif
};
/*** Macros for internal use ***/
/* Thread ID, 16 bits = |VVVVVVVV|SSSSSSSS| */
#define THREAD_ID_VERSION_SHIFT 8
#define THREAD_ID_VERSION_MASK 0xff00
#define THREAD_ID_SLOT_MASK 0x00ff
#define THREAD_ID_INIT(n) ((1u << THREAD_ID_VERSION_SHIFT) | (n))
/* Specify current thread in a function taking an ID. */
#define THREAD_ID_CURRENT ((unsigned int)-1)
#if NUM_CORES > 1
/* Operations to be performed just before stopping a thread and starting
a new one if specified before calling switch_thread */
enum
{
TBOP_CLEAR = 0, /* No operation to do */
TBOP_UNLOCK_CORELOCK, /* Unlock a corelock variable */
TBOP_SWITCH_CORE, /* Call the core switch preparation routine */
};
struct thread_blk_ops
{
struct corelock *cl_p; /* pointer to corelock */
unsigned char flags; /* TBOP_* flags */
};
#endif /* NUM_CORES > 1 */
/* Information kept for each core
* Members are arranged for the same reason as in thread_entry
*/
struct core_entry
{
/* "Active" lists - core is constantly active on these and are never
locked and interrupts do not access them */
struct thread_entry *running; /* threads that are running (RTR) */
struct thread_entry *timeout; /* threads that are on a timeout before
running again */
struct thread_entry *block_task; /* Task going off running list */
#ifdef HAVE_PRIORITY_SCHEDULING
struct priority_distribution rtr; /* Summary of running and ready-to-run
threads */
#endif
long next_tmo_check; /* soonest time to check tmo threads */
#if NUM_CORES > 1
struct thread_blk_ops blk_ops; /* operations to perform when
blocking a thread */
struct corelock rtr_cl; /* Lock for rtr list */
#endif /* NUM_CORES */
};
#ifdef HAVE_PRIORITY_SCHEDULING
#define IF_PRIO(...) __VA_ARGS__
#define IFN_PRIO(...)
#else
#define IF_PRIO(...)
#define IFN_PRIO(...) __VA_ARGS__
#endif
/* Macros generate better code than an inline function is this case */
#if (defined (CPU_PP) || defined (CPU_ARM))
/* atomic */
#if CONFIG_CORELOCK == SW_CORELOCK
#define test_and_set(a, v, cl) \
xchg8((a), (v), (cl))
/* atomic */
#define xchg8(a, v, cl) \
({ uint32_t o; \
corelock_lock(cl); \
o = *(uint8_t *)(a); \
*(uint8_t *)(a) = (v); \
corelock_unlock(cl); \
o; })
#define xchg32(a, v, cl) \
({ uint32_t o; \
corelock_lock(cl); \
o = *(uint32_t *)(a); \
*(uint32_t *)(a) = (v); \
corelock_unlock(cl); \
o; })
#define xchgptr(a, v, cl) \
({ typeof (*(a)) o; \
corelock_lock(cl); \
o = *(a); \
*(a) = (v); \
corelock_unlock(cl); \
o; })
#elif CONFIG_CORELOCK == CORELOCK_SWAP
/* atomic */
#define test_and_set(a, v, ...) \
xchg8((a), (v))
#define xchg8(a, v, ...) \
({ uint32_t o; \
asm volatile( \
"swpb %0, %1, [%2]" \
: "=&r"(o) \
: "r"(v), \
"r"((uint8_t*)(a))); \
o; })
/* atomic */
#define xchg32(a, v, ...) \
({ uint32_t o; \
asm volatile( \
"swp %0, %1, [%2]" \
: "=&r"(o) \
: "r"((uint32_t)(v)), \
"r"((uint32_t*)(a))); \
o; })
/* atomic */
#define xchgptr(a, v, ...) \
({ typeof (*(a)) o; \
asm volatile( \
"swp %0, %1, [%2]" \
: "=&r"(o) \
: "r"(v), "r"(a)); \
o; })
#endif /* locking selection */
#elif defined (CPU_COLDFIRE)
/* atomic */
/* one branch will be optimized away if v is a constant expression */
#define test_and_set(a, v, ...) \
({ uint32_t o = 0; \
if (v) { \
asm volatile ( \
"bset.b #0, (%0)" \
: : "a"((uint8_t*)(a)) \
: "cc"); \
} else { \
asm volatile ( \
"bclr.b #0, (%0)" \
: : "a"((uint8_t*)(a)) \
: "cc"); \
} \
asm volatile ("sne.b %0" \
: "+d"(o)); \
o; })
#elif CONFIG_CPU == SH7034
/* atomic */
#define test_and_set(a, v, ...) \
({ uint32_t o; \
asm volatile ( \
"tas.b @%2 \n" \
"mov #-1, %0 \n" \
"negc %0, %0 \n" \
: "=r"(o) \
: "M"((uint32_t)(v)), /* Value of_v must be 1 */ \
"r"((uint8_t *)(a))); \
o; })
#endif /* CONFIG_CPU == */
/* defaults for no asm version */
#ifndef test_and_set
/* not atomic */
#define test_and_set(a, v, ...) \
({ uint32_t o = *(uint8_t *)(a); \
*(uint8_t *)(a) = (v); \
o; })
#endif /* test_and_set */
#ifndef xchg8
/* not atomic */
#define xchg8(a, v, ...) \
({ uint32_t o = *(uint8_t *)(a); \
*(uint8_t *)(a) = (v); \
o; })
#endif /* xchg8 */
#ifndef xchg32
/* not atomic */
#define xchg32(a, v, ...) \
({ uint32_t o = *(uint32_t *)(a); \
*(uint32_t *)(a) = (v); \
o; })
#endif /* xchg32 */
#ifndef xchgptr
/* not atomic */
#define xchgptr(a, v, ...) \
({ typeof (*(a)) o = *(a); \
*(a) = (v); \
o; })
#endif /* xchgptr */
void core_idle(void);
void core_wake(IF_COP_VOID(unsigned int core));
/* Initialize the scheduler */
void init_threads(void) INIT_ATTR;
/* Allocate a thread in the scheduler */
#define CREATE_THREAD_FROZEN 0x00000001 /* Thread is frozen at create time */
unsigned int create_thread(void (*function)(void),
void* stack, size_t stack_size,
unsigned flags, const char *name
IF_PRIO(, int priority)
IF_COP(, unsigned int core));
/* Set and clear the CPU frequency boost flag for the calling thread */
#ifdef HAVE_SCHEDULER_BOOSTCTRL
void trigger_cpu_boost(void);
void cancel_cpu_boost(void);
#else
#define trigger_cpu_boost()
#define cancel_cpu_boost()
#endif
/* Return thread entry from id */
struct thread_entry *thread_id_entry(unsigned int thread_id);
/* Make a frozed thread runnable (when started with CREATE_THREAD_FROZEN).
* Has no effect on a thread not frozen. */
void thread_thaw(unsigned int thread_id);
/* Wait for a thread to exit */
void thread_wait(unsigned int thread_id);
/* Exit the current thread */
void thread_exit(void);
#if defined(DEBUG) || defined(ROCKBOX_HAS_LOGF)
#define ALLOW_REMOVE_THREAD
/* Remove a thread from the scheduler */
void remove_thread(unsigned int thread_id);
#endif
/* Switch to next runnable thread */
void switch_thread(void);
/* Blocks a thread for at least the specified number of ticks (0 = wait until
* next tick) */
void sleep_thread(int ticks);
/* Indefinitely blocks the current thread on a thread queue */
void block_thread(struct thread_entry *current);
/* Blocks the current thread on a thread queue until explicitely woken or
* the timeout is reached */
void block_thread_w_tmo(struct thread_entry *current, int timeout);
/* Return bit flags for thread wakeup */
#define THREAD_NONE 0x0 /* No thread woken up (exclusive) */
#define THREAD_OK 0x1 /* A thread was woken up */
#define THREAD_SWITCH 0x2 /* Task switch recommended (one or more of
higher priority than current were woken) */
/* A convenience function for waking an entire queue of threads. */
unsigned int thread_queue_wake(struct thread_entry **list);
/* Wakeup a thread at the head of a list */
unsigned int wakeup_thread(struct thread_entry **list);
#ifdef HAVE_PRIORITY_SCHEDULING
int thread_set_priority(unsigned int thread_id, int priority);
int thread_get_priority(unsigned int thread_id);
#endif /* HAVE_PRIORITY_SCHEDULING */
#ifdef HAVE_IO_PRIORITY
void thread_set_io_priority(unsigned int thread_id, int io_priority);
int thread_get_io_priority(unsigned int thread_id);
#endif /* HAVE_IO_PRIORITY */
#if NUM_CORES > 1
unsigned int switch_core(unsigned int new_core);
#endif
unsigned int thread_get_current(void);
/* Debugging info - only! */
int thread_stack_usage(const struct thread_entry *thread);
#if NUM_CORES > 1
int idle_stack_usage(unsigned int core);
#endif
void thread_get_name(char *buffer, int size,
struct thread_entry *thread);
#ifdef RB_PROFILE
void profile_thread(void);
#endif
#endif /* THREAD_H */