source: libcfa/src/concurrency/kernel_private.hfa @ e67a82d

arm-ehjacob/cs343-translationnew-ast-unique-expr
Last change on this file since e67a82d was e67a82d, checked in by Peter A. Buhr <pabuhr@…>, 16 months ago

fix conflicts

  • Property mode set to 100644
File size: 9.4 KB
Line 
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( struct __processor_id_t *, $thread * )
36#if defined(NDEBUG) || (!defined(__CFA_DEBUG__) && !defined(__CFA_VERIFY__))
37        __attribute__((nonnull (2)))
38#endif
39;
40
41//Block current thread and release/wake-up the following resources
42void __leave_thread() __attribute__((noreturn));
43
44//-----------------------------------------------------------------------------
45// Processor
46void main(processorCtx_t *);
47
48void * __create_pthread( pthread_t *, void * (*)(void *), void * );
49
50
51
52extern cluster * mainCluster;
53
54//-----------------------------------------------------------------------------
55// Threads
56extern "C" {
57      void __cfactx_invoke_thread(void (*main)(void *), void * this);
58}
59
60__cfaabi_dbg_debug_do(
61        extern void __cfaabi_dbg_thread_register  ( $thread * thrd );
62        extern void __cfaabi_dbg_thread_unregister( $thread * thrd );
63)
64
65// KERNEL ONLY unpark with out disabling interrupts
66void __unpark( struct __processor_id_t *, $thread * thrd __cfaabi_dbg_ctx_param2 );
67
68static inline bool __post(single_sem & this, struct __processor_id_t * id) {
69        for() {
70                struct $thread * expected = this.ptr;
71                if(expected == 1p) return false;
72                if(expected == 0p) {
73                        if(__atomic_compare_exchange_n(&this.ptr, &expected, 1p, false, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST)) {
74                                return false;
75                        }
76                }
77                else {
78                        if(__atomic_compare_exchange_n(&this.ptr, &expected, 0p, false, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST)) {
79                                __unpark( id, expected __cfaabi_dbg_ctx2 );
80                                return true;
81                        }
82                }
83        }
84}
85
86//-----------------------------------------------------------------------------
87// Utils
88void doregister( struct cluster * cltr, struct $thread & thrd );
89void unregister( struct cluster * cltr, struct $thread & thrd );
90
91//-----------------------------------------------------------------------------
92// I/O
93void ^?{}(io_context & this, bool );
94
95//=======================================================================
96// Cluster lock API
97//=======================================================================
98// Cells use by the reader writer lock
99// while not generic it only relies on a opaque pointer
100struct __attribute__((aligned(128))) __scheduler_lock_id_t {
101        // Spin lock used as the underlying lock
102        volatile bool lock;
103
104        // Handle pointing to the proc owning this cell
105        // Used for allocating cells and debugging
106        __processor_id_t * volatile handle;
107
108        #ifdef __CFA_WITH_VERIFY__
109                // Debug, check if this is owned for reading
110                bool owned;
111        #endif
112};
113
114static_assert( sizeof(struct __scheduler_lock_id_t) <= __alignof(struct __scheduler_lock_id_t));
115
116// Lock-Free registering/unregistering of threads
117// Register a processor to a given cluster and get its unique id in return
118unsigned doregister( struct __processor_id_t * proc );
119
120// Unregister a processor from a given cluster using its id, getting back the original pointer
121void     unregister( struct __processor_id_t * proc );
122
123//-----------------------------------------------------------------------
124// Cluster idle lock/unlock
125static inline void lock(__cluster_idles & this) {
126        for() {
127                uint64_t l = this.lock;
128                if(
129                        (0 == (l % 2))
130                        && __atomic_compare_exchange_n(&this.lock, &l, l + 1, false, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST)
131                ) return;
132                Pause();
133        }
134}
135
136static inline void unlock(__cluster_idles & this) {
137        /* paranoid */ verify( 1 == (this.lock % 2) );
138        __atomic_fetch_add( &this.lock, 1, __ATOMIC_SEQ_CST );
139}
140
141//=======================================================================
142// Reader-writer lock implementation
143// Concurrent with doregister/unregister,
144//    i.e., threads can be added at any point during or between the entry/exit
145
146//-----------------------------------------------------------------------
147// simple spinlock underlying the RWLock
148// Blocking acquire
149static inline void __atomic_acquire(volatile bool * ll) {
150        while( __builtin_expect(__atomic_exchange_n(ll, (bool)true, __ATOMIC_SEQ_CST), false) ) {
151                while(__atomic_load_n(ll, (int)__ATOMIC_RELAXED))
152                        Pause();
153        }
154        /* paranoid */ verify(*ll);
155}
156
157// Non-Blocking acquire
158static inline bool __atomic_try_acquire(volatile bool * ll) {
159        return !__atomic_exchange_n(ll, (bool)true, __ATOMIC_SEQ_CST);
160}
161
162// Release
163static inline void __atomic_unlock(volatile bool * ll) {
164        /* paranoid */ verify(*ll);
165        __atomic_store_n(ll, (bool)false, __ATOMIC_RELEASE);
166}
167
168//-----------------------------------------------------------------------
169// Reader-Writer lock protecting the ready-queues
170// while this lock is mostly generic some aspects
171// have been hard-coded to for the ready-queue for
172// simplicity and performance
173struct __scheduler_RWLock_t {
174        // total cachelines allocated
175        unsigned int max;
176
177        // cachelines currently in use
178        volatile unsigned int alloc;
179
180        // cachelines ready to itereate over
181        // (!= to alloc when thread is in second half of doregister)
182        volatile unsigned int ready;
183
184        // writer lock
185        volatile bool lock;
186
187        // data pointer
188        __scheduler_lock_id_t * data;
189};
190
191void  ?{}(__scheduler_RWLock_t & this);
192void ^?{}(__scheduler_RWLock_t & this);
193
194extern __scheduler_RWLock_t * __scheduler_lock;
195
196//-----------------------------------------------------------------------
197// Reader side : acquire when using the ready queue to schedule but not
198//  creating/destroying queues
199static inline void ready_schedule_lock( struct __processor_id_t * proc) with(*__scheduler_lock) {
200        unsigned iproc = proc->id;
201        /*paranoid*/ verify(data[iproc].handle == proc);
202        /*paranoid*/ verify(iproc < ready);
203
204        // Step 1 : make sure no writer are in the middle of the critical section
205        while(__atomic_load_n(&lock, (int)__ATOMIC_RELAXED))
206                Pause();
207
208        // Fence needed because we don't want to start trying to acquire the lock
209        // before we read a false.
210        // Not needed on x86
211        // std::atomic_thread_fence(std::memory_order_seq_cst);
212
213        // Step 2 : acquire our local lock
214        __atomic_acquire( &data[iproc].lock );
215        /*paranoid*/ verify(data[iproc].lock);
216
217        #ifdef __CFA_WITH_VERIFY__
218                // Debug, check if this is owned for reading
219                data[iproc].owned = true;
220        #endif
221}
222
223static inline void ready_schedule_unlock( struct __processor_id_t * proc) with(*__scheduler_lock) {
224        unsigned iproc = proc->id;
225        /*paranoid*/ verify(data[iproc].handle == proc);
226        /*paranoid*/ verify(iproc < ready);
227        /*paranoid*/ verify(data[iproc].lock);
228        /*paranoid*/ verify(data[iproc].owned);
229        #ifdef __CFA_WITH_VERIFY__
230                // Debug, check if this is owned for reading
231                data[iproc].owned = false;
232        #endif
233        __atomic_unlock(&data[iproc].lock);
234}
235
236#ifdef __CFA_WITH_VERIFY__
237        static inline bool ready_schedule_islocked( struct __processor_id_t * proc) {
238                return __scheduler_lock->data[proc->id].owned;
239        }
240
241        static inline bool ready_mutate_islocked() {
242                return __scheduler_lock->lock;
243        }
244#endif
245
246//-----------------------------------------------------------------------
247// Writer side : acquire when changing the ready queue, e.g. adding more
248//  queues or removing them.
249uint_fast32_t ready_mutate_lock( void );
250
251void ready_mutate_unlock( uint_fast32_t /* value returned by lock */ );
252
253//=======================================================================
254// Ready-Queue API
255//-----------------------------------------------------------------------
256// pop thread from the ready queue of a cluster
257// returns 0p if empty
258__attribute__((hot)) bool query(struct cluster * cltr);
259
260//-----------------------------------------------------------------------
261// push thread onto a ready queue for a cluster
262// returns true if the list was previously empty, false otherwise
263__attribute__((hot)) bool push(struct cluster * cltr, struct $thread * thrd);
264
265//-----------------------------------------------------------------------
266// pop thread from the ready queue of a cluster
267// returns 0p if empty
268// May return 0p spuriously
269__attribute__((hot)) struct $thread * pop(struct cluster * cltr);
270
271//-----------------------------------------------------------------------
272// pop thread from the ready queue of a cluster
273// returns 0p if empty
274// guaranteed to find any threads added before this call
275__attribute__((hot)) struct $thread * pop_slow(struct cluster * cltr);
276
277//-----------------------------------------------------------------------
278// remove thread from the ready queue of a cluster
279// returns bool if it wasn't found
280bool remove_head(struct cluster * cltr, struct $thread * thrd);
281
282//-----------------------------------------------------------------------
283// Increase the width of the ready queue (number of lanes) by 4
284void ready_queue_grow  (struct cluster * cltr, int target);
285
286//-----------------------------------------------------------------------
287// Decrease the width of the ready queue (number of lanes) by 4
288void ready_queue_shrink(struct cluster * cltr, int target);
289
290
291// Local Variables: //
292// mode: c //
293// tab-width: 4 //
294// End: //
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