bthread.cpp 12 KB
Newer Older
gejun's avatar
gejun committed
1
// bthread - A M:N threading library to make applications more concurrent.
gejun's avatar
gejun committed
2
// Copyright (c) 2012 Baidu, Inc.
gejun's avatar
gejun committed
3 4 5 6 7 8 9 10 11 12 13 14
// 
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// 
//     http://www.apache.org/licenses/LICENSE-2.0
// 
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
gejun's avatar
gejun committed
15 16 17 18 19

// Author: Ge,Jun (gejun@baidu.com)
// Date: Tue Jul 10 17:40:58 CST 2012

#include <gflags/gflags.h>
20 21
#include "butil/macros.h"                       // BAIDU_CASSERT
#include "butil/logging.h"
gejun's avatar
gejun committed
22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42
#include "bthread/task_group.h"                // TaskGroup
#include "bthread/task_control.h"              // TaskControl
#include "bthread/timer_thread.h"
#include "bthread/list_of_abafree_id.h"
#include "bthread/bthread.h"

namespace bthread {

DEFINE_int32(bthread_concurrency, 8 + BTHREAD_EPOLL_THREAD_NUM,
             "Number of pthread workers");
static bool never_set_bthread_concurrency = true;

static bool validate_bthread_concurrency(const char*, int32_t val) {
    // bthread_setconcurrency sets the flag on success path which should
    // not be strictly in a validator. But it's OK for a int flag.
    return bthread_setconcurrency(val) == 0;
}
const int ALLOW_UNUSED register_FLAGS_bthread_concurrency = 
    ::google::RegisterFlagValidator(&FLAGS_bthread_concurrency,
                                    validate_bthread_concurrency);

43
BAIDU_CASSERT(sizeof(TaskControl*) == sizeof(butil::atomic<TaskControl*>), atomic_size_match);
gejun's avatar
gejun committed
44 45 46 47 48 49 50 51 52 53 54 55 56 57 58

pthread_mutex_t g_task_control_mutex = PTHREAD_MUTEX_INITIALIZER;
// Referenced in rpc, needs to be extern.
// Notice that we can't declare the variable as atomic<TaskControl*> which
// may not initialized before creating bthreads before main().
TaskControl* g_task_control = NULL;

extern BAIDU_THREAD_LOCAL TaskGroup* tls_task_group;
extern void (*g_worker_startfn)();

inline TaskControl* get_task_control() {
    return g_task_control;
}

inline TaskControl* get_or_new_task_control() {
59 60
    butil::atomic<TaskControl*>* p = (butil::atomic<TaskControl*>*)&g_task_control;
    TaskControl* c = p->load(butil::memory_order_consume);
gejun's avatar
gejun committed
61 62 63 64
    if (c != NULL) {
        return c;
    }
    BAIDU_SCOPED_LOCK(g_task_control_mutex);
65
    c = p->load(butil::memory_order_consume);
gejun's avatar
gejun committed
66 67 68 69 70 71 72 73 74 75 76 77
    if (c != NULL) {
        return c;
    }
    c = new (std::nothrow) TaskControl;
    if (NULL == c) {
        return NULL;
    }
    if (c->init(FLAGS_bthread_concurrency) != 0) {
        LOG(ERROR) << "Fail to init g_task_control";
        delete c;
        return NULL;
    }
78
    p->store(c, butil::memory_order_release);
gejun's avatar
gejun committed
79 80 81 82 83
    return c;
}

__thread TaskGroup* tls_task_group_nosignal = NULL;

84 85 86 87 88
BASE_FORCE_INLINE int
start_from_non_worker(bthread_t* __restrict tid,
                      const bthread_attr_t* __restrict attr,
                      void * (*fn)(void*),
                      void* __restrict arg) {
gejun's avatar
gejun committed
89 90 91 92 93 94 95 96 97 98 99 100 101 102
    TaskControl* c = get_or_new_task_control();
    if (NULL == c) {
        return ENOMEM;
    }
    if (attr != NULL && (attr->flags & BTHREAD_NOSIGNAL)) {
        // Remember the TaskGroup to insert NOSIGNAL tasks for 2 reasons:
        // 1. NOSIGNAL is often for creating many bthreads in batch,
        //    inserting into the same TaskGroup maximizes the batch.
        // 2. bthread_flush() needs to know which TaskGroup to flush.
        TaskGroup* g = tls_task_group_nosignal;
        if (NULL == g) {
            g = c->choose_one_group();
            tls_task_group_nosignal = g;
        }
103
        return g->start_background<true>(tid, attr, fn, arg);
gejun's avatar
gejun committed
104
    }
105 106
    return c->choose_one_group()->start_background<true>(
        tid, attr, fn, arg);
gejun's avatar
gejun committed
107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153
}

int stop_butex_wait(bthread_t tid);

struct TidTraits {
    static const size_t BLOCK_SIZE = 63;
    static const size_t MAX_ENTRIES = 65536;
    static const bthread_t ID_INIT;
    static bool exists(bthread_t id) { return bthread::TaskGroup::exists(id); }
};
const bthread_t TidTraits::ID_INIT = INVALID_BTHREAD;

typedef ListOfABAFreeId<bthread_t, TidTraits> TidList;

struct TidStopper {
    void operator()(bthread_t id) const { bthread_stop(id); }
};
struct TidJoiner {
    void operator()(bthread_t & id) const {
        bthread_join(id, NULL);
        id = INVALID_BTHREAD;
    }
};

}  // namespace bthread

extern "C" {

int bthread_start_urgent(bthread_t* __restrict tid,
                         const bthread_attr_t* __restrict attr,
                         void * (*fn)(void*),
                         void* __restrict arg) __THROW {
    bthread::TaskGroup* g = bthread::tls_task_group;
    if (g) {
        // start from worker
        return bthread::TaskGroup::start_foreground(&g, tid, attr, fn, arg);
    }
    return bthread::start_from_non_worker(tid, attr, fn, arg);
}

int bthread_start_background(bthread_t* __restrict tid,
                             const bthread_attr_t* __restrict attr,
                             void * (*fn)(void*),
                             void* __restrict arg) __THROW {
    bthread::TaskGroup* g = bthread::tls_task_group;
    if (g) {
        // start from worker
154
        return g->start_background<false>(tid, attr, fn, arg);
gejun's avatar
gejun committed
155 156 157 158 159 160 161
    }
    return bthread::start_from_non_worker(tid, attr, fn, arg);
}

void bthread_flush() __THROW {
    bthread::TaskGroup* g = bthread::tls_task_group;
    if (g) {
162
        return g->flush_nosignal_tasks();
gejun's avatar
gejun committed
163 164 165 166 167
    }
    g = bthread::tls_task_group_nosignal;
    if (g) {
        // NOSIGNAL tasks were created in this non-worker.
        bthread::tls_task_group_nosignal = NULL;
168
        return g->flush_nosignal_tasks_remote();
gejun's avatar
gejun committed
169 170 171 172 173 174 175
    }
}

int bthread_stop(bthread_t tid) __THROW {
    if (bthread::stop_butex_wait(tid) < 0) {
        return errno;
    }
176 177 178 179 180 181 182
    bthread::TaskGroup* g = bthread::tls_task_group;
    if (!g) {
        bthread::TaskControl* c = bthread::get_or_new_task_control();
        if (!c) {
            return ENOMEM;
        }
        g = c->choose_one_group();
gejun's avatar
gejun committed
183
    }
184
    return g->stop_usleep(tid);
gejun's avatar
gejun committed
185 186 187 188 189 190 191 192 193 194 195 196 197 198
}

int bthread_stopped(bthread_t tid) __THROW {
    return bthread::TaskGroup::stopped(tid);
}

bthread_t bthread_self(void) __THROW {
    bthread::TaskGroup* g = bthread::tls_task_group;
    // note: return 0 for main tasks now, which include main thread and
    // all work threads. So that we can identify main tasks from logs
    // more easily. This is probably questionable in future.
    if (g != NULL && !g->is_current_main_task()/*note*/) {
        return g->current_tid();
    }
199
    return INVALID_BTHREAD;
gejun's avatar
gejun committed
200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328
}

int bthread_equal(bthread_t t1, bthread_t t2) __THROW {
    return t1 == t2;
}

void bthread_exit(void* retval) {
    bthread::TaskGroup* g = bthread::tls_task_group;
    if (g != NULL && !g->is_current_main_task()) {
        throw bthread::ExitException(retval);
    } else {
        pthread_exit(retval);
    }
}

int bthread_join(bthread_t tid, void** thread_return) __THROW {
    return bthread::TaskGroup::join(tid, thread_return);
}

int bthread_attr_init(bthread_attr_t* a) __THROW {
    *a = BTHREAD_ATTR_NORMAL;
    return 0;
}

int bthread_attr_destroy(bthread_attr_t*) __THROW {
    return 0;
}

int bthread_getattr(bthread_t tid, bthread_attr_t* attr) __THROW {
    return bthread::TaskGroup::get_attr(tid, attr);
}

int bthread_getconcurrency(void) __THROW {
    return bthread::FLAGS_bthread_concurrency;
}

int bthread_setconcurrency(int num) __THROW {
    if (num < BTHREAD_MIN_CONCURRENCY || num > BTHREAD_MAX_CONCURRENCY) {
        LOG(ERROR) << "Invalid concurrency=" << num;
        return EINVAL;
    }
    bthread::TaskControl* c = bthread::get_task_control();
    if (c != NULL) {
        if (num < c->concurrency()) {
            return EPERM;
        } else if (num == c->concurrency()) {
            return 0;
        }
    }
    BAIDU_SCOPED_LOCK(bthread::g_task_control_mutex);
    c = bthread::get_task_control();
    if (c == NULL) {
        if (bthread::never_set_bthread_concurrency) {
            bthread::never_set_bthread_concurrency = false;
            bthread::FLAGS_bthread_concurrency = num;
        } else if (num > bthread::FLAGS_bthread_concurrency) {
            bthread::FLAGS_bthread_concurrency = num;
        }
        return 0;
    }
    if (bthread::FLAGS_bthread_concurrency != c->concurrency()) {
        LOG(ERROR) << "CHECK failed: bthread_concurrency="
                   << bthread::FLAGS_bthread_concurrency
                   << " != tc_concurrency=" << c->concurrency();
        bthread::FLAGS_bthread_concurrency = c->concurrency();
    }
    if (num > bthread::FLAGS_bthread_concurrency) {
        // Create more workers if needed.
        bthread::FLAGS_bthread_concurrency +=
            c->add_workers(num - bthread::FLAGS_bthread_concurrency);
        return 0;
    }
    return (num == bthread::FLAGS_bthread_concurrency ? 0 : EPERM);
}

int bthread_about_to_quit() __THROW {
    bthread::TaskGroup* g = bthread::tls_task_group;
    if (g != NULL) {
        g->current_task()->about_to_quit = true;
        return 0;
    }
    return EPERM;
}

int bthread_timer_add(bthread_timer_t* id, timespec abstime,
                      void (*on_timer)(void*), void* arg) __THROW {
    bthread::TaskControl* c = bthread::get_or_new_task_control();
    if (c == NULL) {
        return ENOMEM;
    }
    bthread::TimerThread* tt = bthread::get_or_create_global_timer_thread();
    if (tt == NULL) {
        return ENOMEM;
    }
    bthread_timer_t tmp = tt->schedule(on_timer, arg, abstime);
    if (tmp != 0) {
        *id = tmp;
        return 0;
    }
    return ESTOP;
}

int bthread_timer_del(bthread_timer_t id) __THROW {
    bthread::TaskControl* c = bthread::get_task_control();
    if (c != NULL) {
        bthread::TimerThread* tt = bthread::get_global_timer_thread();
        if (tt == NULL) {
            return EINVAL;
        }
        const int state = tt->unschedule(id);
        if (state >= 0) {
            return state;
        }
    }
    return EINVAL;
}

int bthread_usleep(uint64_t microseconds) __THROW {
    bthread::TaskGroup* g = bthread::tls_task_group;
    if (NULL != g && !g->is_current_pthread_task()) {
        return bthread::TaskGroup::usleep(&g, microseconds);
    }
    // TODO: return ESTOP for pthread_task
    return ::usleep(microseconds);
}

int bthread_yield(void) __THROW {
    bthread::TaskGroup* g = bthread::tls_task_group;
    if (NULL != g && !g->is_current_pthread_task()) {
329 330
        bthread::TaskGroup::yield(&g);
        return 0;
gejun's avatar
gejun committed
331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393
    }
    return pthread_yield();
}

int bthread_set_worker_startfn(void (*start_fn)()) __THROW {
    if (start_fn == NULL) {
        return EINVAL;
    }
    bthread::g_worker_startfn = start_fn;
    return 0;
}

void bthread_stop_world() __THROW {
    bthread::TaskControl* c = bthread::get_task_control();
    if (c != NULL) {
        c->stop_and_join();
    }
}

int bthread_list_init(bthread_list_t* list,
                      unsigned /*size*/,
                      unsigned /*conflict_size*/) __THROW {
    list->impl = new (std::nothrow) bthread::TidList;
    if (NULL == list->impl) {
        return ENOMEM;
    }
    // Set unused fields to zero as well.
    list->head = 0;
    list->size = 0;
    list->conflict_head = 0;
    list->conflict_size = 0;
    return 0;
}

void bthread_list_destroy(bthread_list_t* list) __THROW {
    delete static_cast<bthread::TidList*>(list->impl);
    list->impl = NULL;
}

int bthread_list_add(bthread_list_t* list, bthread_t id) __THROW {
    if (list->impl == NULL) {
        return EINVAL;
    }
    return static_cast<bthread::TidList*>(list->impl)->add(id);
}

int bthread_list_stop(bthread_list_t* list) __THROW {
    if (list->impl == NULL) {
        return EINVAL;
    }
    static_cast<bthread::TidList*>(list->impl)->apply(bthread::TidStopper());
    return 0;
}

int bthread_list_join(bthread_list_t* list) __THROW {
    if (list->impl == NULL) {
        return EINVAL;
    }
    static_cast<bthread::TidList*>(list->impl)->apply(bthread::TidJoiner());
    return 0;
}
    
}  // extern "C"