source: libcfa/src/concurrency/kernel_private.hfa @ bfcf6b9

arm-ehjacob/cs343-translationnew-ast-unique-expr
Last change on this file since bfcf6b9 was bfcf6b9, checked in by Thierry Delisle <tdelisle@…>, 10 months ago

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1//
2// Cforall Version 1.0.0 Copyright (C) 2016 University of Waterloo
3//
4// The contents of this file are covered under the licence agreement in the
5// file "LICENCE" distributed with Cforall.
6//
7// kernel_private.hfa --
8//
9// Author           : Thierry Delisle
10// Created On       : Mon Feb 13 12:27:26 2017
11// Last Modified By : Peter A. Buhr
12// Last Modified On : Wed Aug 12 08:21:33 2020
13// Update Count     : 9
14//
15
16#pragma once
17
18#include "kernel.hfa"
19#include "thread.hfa"
20
21#include "alarm.hfa"
22#include "stats.hfa"
23
24//-----------------------------------------------------------------------------
25// Scheduler
26
27struct __attribute__((aligned(128))) __scheduler_lock_id_t;
28
29extern "C" {
30        void disable_interrupts() OPTIONAL_THREAD;
31        void enable_interrupts_noPoll();
32        void enable_interrupts( __cfaabi_dbg_ctx_param );
33}
34
35void __schedule_thread( $thread * )
36#if defined(NDEBUG) || (!defined(__CFA_DEBUG__) && !defined(__CFA_VERIFY__))
37        __attribute__((nonnull (1)))
38#endif
39;
40
41extern bool __preemption_enabled();
42
43//release/wake-up the following resources
44void __thread_finish( $thread * thrd );
45
46//-----------------------------------------------------------------------------
47// Processor
48void main(processorCtx_t *);
49
50void * __create_pthread( pthread_t *, void * (*)(void *), void * );
51void __destroy_pthread( pthread_t pthread, void * stack, void ** retval );
52
53
54
55extern cluster * mainCluster;
56
57//-----------------------------------------------------------------------------
58// Threads
59extern "C" {
60      void __cfactx_invoke_thread(void (*main)(void *), void * this);
61}
62
63__cfaabi_dbg_debug_do(
64        extern void __cfaabi_dbg_thread_register  ( $thread * thrd );
65        extern void __cfaabi_dbg_thread_unregister( $thread * thrd );
66)
67
68#define TICKET_BLOCKED (-1) // thread is blocked
69#define TICKET_RUNNING ( 0) // thread is running
70#define TICKET_UNBLOCK ( 1) // thread should ignore next block
71
72//-----------------------------------------------------------------------------
73// Utils
74void doregister( struct cluster * cltr, struct $thread & thrd );
75void unregister( struct cluster * cltr, struct $thread & thrd );
76
77//-----------------------------------------------------------------------------
78// I/O
79void ^?{}(io_context & this, bool );
80
81//=======================================================================
82// Cluster lock API
83//=======================================================================
84// Cells use by the reader writer lock
85// while not generic it only relies on a opaque pointer
86struct __attribute__((aligned(128))) __scheduler_lock_id_t {
87        // Spin lock used as the underlying lock
88        volatile bool lock;
89
90        // Handle pointing to the proc owning this cell
91        // Used for allocating cells and debugging
92        __processor_id_t * volatile handle;
93
94        #ifdef __CFA_WITH_VERIFY__
95                // Debug, check if this is owned for reading
96                bool owned;
97        #endif
98};
99
100static_assert( sizeof(struct __scheduler_lock_id_t) <= __alignof(struct __scheduler_lock_id_t));
101
102// Lock-Free registering/unregistering of threads
103// Register a processor to a given cluster and get its unique id in return
104unsigned doregister( struct __processor_id_t * proc );
105
106// Unregister a processor from a given cluster using its id, getting back the original pointer
107void     unregister( struct __processor_id_t * proc );
108
109//-----------------------------------------------------------------------
110// Cluster idle lock/unlock
111static inline void lock(__cluster_idles & this) {
112        for() {
113                uint64_t l = this.lock;
114                if(
115                        (0 == (l % 2))
116                        && __atomic_compare_exchange_n(&this.lock, &l, l + 1, false, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST)
117                ) return;
118                Pause();
119        }
120}
121
122static inline void unlock(__cluster_idles & this) {
123        /* paranoid */ verify( 1 == (this.lock % 2) );
124        __atomic_fetch_add( &this.lock, 1, __ATOMIC_SEQ_CST );
125}
126
127//=======================================================================
128// Reader-writer lock implementation
129// Concurrent with doregister/unregister,
130//    i.e., threads can be added at any point during or between the entry/exit
131
132//-----------------------------------------------------------------------
133// simple spinlock underlying the RWLock
134// Blocking acquire
135static inline void __atomic_acquire(volatile bool * ll) {
136        while( __builtin_expect(__atomic_exchange_n(ll, (bool)true, __ATOMIC_SEQ_CST), false) ) {
137                while(__atomic_load_n(ll, (int)__ATOMIC_RELAXED))
138                        Pause();
139        }
140        /* paranoid */ verify(*ll);
141}
142
143// Non-Blocking acquire
144static inline bool __atomic_try_acquire(volatile bool * ll) {
145        return !__atomic_exchange_n(ll, (bool)true, __ATOMIC_SEQ_CST);
146}
147
148// Release
149static inline void __atomic_unlock(volatile bool * ll) {
150        /* paranoid */ verify(*ll);
151        __atomic_store_n(ll, (bool)false, __ATOMIC_RELEASE);
152}
153
154//-----------------------------------------------------------------------
155// Reader-Writer lock protecting the ready-queues
156// while this lock is mostly generic some aspects
157// have been hard-coded to for the ready-queue for
158// simplicity and performance
159struct __scheduler_RWLock_t {
160        // total cachelines allocated
161        unsigned int max;
162
163        // cachelines currently in use
164        volatile unsigned int alloc;
165
166        // cachelines ready to itereate over
167        // (!= to alloc when thread is in second half of doregister)
168        volatile unsigned int ready;
169
170        // writer lock
171        volatile bool lock;
172
173        // data pointer
174        __scheduler_lock_id_t * data;
175};
176
177void  ?{}(__scheduler_RWLock_t & this);
178void ^?{}(__scheduler_RWLock_t & this);
179
180extern __scheduler_RWLock_t * __scheduler_lock;
181
182//-----------------------------------------------------------------------
183// Reader side : acquire when using the ready queue to schedule but not
184//  creating/destroying queues
185static inline void ready_schedule_lock(void) with(*__scheduler_lock) {
186        /* paranoid */ verify( ! __preemption_enabled() );
187        /* paranoid */ verify( kernelTLS().this_proc_id );
188
189        unsigned iproc = kernelTLS().this_proc_id->id;
190        /*paranoid*/ verify(data[iproc].handle == kernelTLS().this_proc_id);
191        /*paranoid*/ verify(iproc < ready);
192
193        // Step 1 : make sure no writer are in the middle of the critical section
194        while(__atomic_load_n(&lock, (int)__ATOMIC_RELAXED))
195                Pause();
196
197        // Fence needed because we don't want to start trying to acquire the lock
198        // before we read a false.
199        // Not needed on x86
200        // std::atomic_thread_fence(std::memory_order_seq_cst);
201
202        // Step 2 : acquire our local lock
203        __atomic_acquire( &data[iproc].lock );
204        /*paranoid*/ verify(data[iproc].lock);
205
206        #ifdef __CFA_WITH_VERIFY__
207                // Debug, check if this is owned for reading
208                data[iproc].owned = true;
209        #endif
210}
211
212static inline void ready_schedule_unlock(void) with(*__scheduler_lock) {
213        /* paranoid */ verify( ! __preemption_enabled() );
214        /* paranoid */ verify( kernelTLS().this_proc_id );
215
216        unsigned iproc = kernelTLS().this_proc_id->id;
217        /*paranoid*/ verify(data[iproc].handle == kernelTLS().this_proc_id);
218        /*paranoid*/ verify(iproc < ready);
219        /*paranoid*/ verify(data[iproc].lock);
220        /*paranoid*/ verify(data[iproc].owned);
221        #ifdef __CFA_WITH_VERIFY__
222                // Debug, check if this is owned for reading
223                data[iproc].owned = false;
224        #endif
225        __atomic_unlock(&data[iproc].lock);
226}
227
228#ifdef __CFA_WITH_VERIFY__
229        static inline bool ready_schedule_islocked(void) {
230                /* paranoid */ verify( ! __preemption_enabled() );
231                /*paranoid*/ verify( kernelTLS().this_proc_id );
232                __processor_id_t * proc = kernelTLS().this_proc_id;
233                return __scheduler_lock->data[proc->id].owned;
234        }
235
236        static inline bool ready_mutate_islocked() {
237                return __scheduler_lock->lock;
238        }
239#endif
240
241//-----------------------------------------------------------------------
242// Writer side : acquire when changing the ready queue, e.g. adding more
243//  queues or removing them.
244uint_fast32_t ready_mutate_lock( void );
245
246void ready_mutate_unlock( uint_fast32_t /* value returned by lock */ );
247
248//=======================================================================
249// Ready-Queue API
250//-----------------------------------------------------------------------
251// pop thread from the ready queue of a cluster
252// returns 0p if empty
253__attribute__((hot)) bool query(struct cluster * cltr);
254
255//-----------------------------------------------------------------------
256// push thread onto a ready queue for a cluster
257// returns true if the list was previously empty, false otherwise
258__attribute__((hot)) bool push(struct cluster * cltr, struct $thread * thrd);
259
260//-----------------------------------------------------------------------
261// pop thread from the ready queue of a cluster
262// returns 0p if empty
263// May return 0p spuriously
264__attribute__((hot)) struct $thread * pop(struct cluster * cltr);
265
266//-----------------------------------------------------------------------
267// pop thread from the ready queue of a cluster
268// returns 0p if empty
269// guaranteed to find any threads added before this call
270__attribute__((hot)) struct $thread * pop_slow(struct cluster * cltr);
271
272//-----------------------------------------------------------------------
273// remove thread from the ready queue of a cluster
274// returns bool if it wasn't found
275bool remove_head(struct cluster * cltr, struct $thread * thrd);
276
277//-----------------------------------------------------------------------
278// Increase the width of the ready queue (number of lanes) by 4
279void ready_queue_grow  (struct cluster * cltr, int target);
280
281//-----------------------------------------------------------------------
282// Decrease the width of the ready queue (number of lanes) by 4
283void ready_queue_shrink(struct cluster * cltr, int target);
284
285
286// Local Variables: //
287// mode: c //
288// tab-width: 4 //
289// End: //
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