Current File : //usr/include/mysql/server/private/threadpool.h
/* Copyright (C) 2012, 2020, MariaDB
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; version 2 of the License.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1335 USA */
#pragma once
#ifdef HAVE_POOL_OF_THREADS
#define MAX_THREAD_GROUPS 100000
/* Threadpool parameters */
extern uint threadpool_min_threads; /* Minimum threads in pool */
extern uint threadpool_idle_timeout; /* Shutdown idle worker threads after this timeout */
extern uint threadpool_size; /* Number of parallel executing threads */
extern uint threadpool_max_size;
extern uint threadpool_stall_limit; /* time interval in milliseconds for stall checks*/
extern uint threadpool_max_threads; /* Maximum threads in pool */
extern uint threadpool_oversubscribe; /* Maximum active threads in group */
extern uint threadpool_prio_kickup_timer; /* Time before low prio item gets prio boost */
extern my_bool threadpool_exact_stats; /* Better queueing time stats for information_schema, at small performance cost */
extern my_bool threadpool_dedicated_listener; /* Listener thread does not pick up work items. */
#ifdef _WIN32
extern uint threadpool_mode; /* Thread pool implementation , windows or generic */
#define TP_MODE_WINDOWS 0
#define TP_MODE_GENERIC 1
#endif
#define DEFAULT_THREADPOOL_STALL_LIMIT 500U
struct TP_connection;
struct st_vio;
extern void tp_callback(TP_connection *c);
extern void tp_timeout_handler(TP_connection *c);
/*
Threadpool statistics
*/
struct TP_STATISTICS
{
/* Current number of worker thread. */
Atomic_counter<uint32_t> num_worker_threads;
};
extern TP_STATISTICS tp_stats;
/* Functions to set threadpool parameters */
extern void tp_set_min_threads(uint val);
extern void tp_set_max_threads(uint val);
extern void tp_set_threadpool_size(uint val);
extern void tp_set_threadpool_stall_limit(uint val);
extern int tp_get_idle_thread_count();
extern int tp_get_thread_count();
enum TP_PRIORITY {
TP_PRIORITY_HIGH,
TP_PRIORITY_LOW,
TP_PRIORITY_AUTO
};
enum TP_STATE
{
TP_STATE_IDLE,
TP_STATE_RUNNING,
TP_STATE_PENDING
};
/*
Connection structure, encapsulates THD + structures for asynchronous
IO and pool.
Platform specific parts are specified in subclasses called connection_t,
inside threadpool_win.cc and threadpool_unix.cc
*/
class CONNECT;
struct TP_connection
{
THD* thd;
CONNECT* connect;
TP_STATE state;
TP_PRIORITY priority;
TP_connection(CONNECT *c) :
thd(0),
connect(c),
state(TP_STATE_IDLE),
priority(TP_PRIORITY_HIGH)
{}
virtual ~TP_connection() = default;
/* Initialize io structures windows threadpool, epoll etc */
virtual int init() = 0;
virtual void set_io_timeout(int sec) = 0;
/* Read for the next client command (async) with specified timeout */
virtual int start_io() = 0;
virtual void wait_begin(int type)= 0;
virtual void wait_end() = 0;
IF_WIN(virtual,) void init_vio(st_vio *){};
};
struct TP_pool
{
virtual ~TP_pool() = default;
virtual int init()= 0;
virtual TP_connection *new_connection(CONNECT *)= 0;
virtual void add(TP_connection *c)= 0;
virtual int set_max_threads(uint){ return 0; }
virtual int set_min_threads(uint){ return 0; }
virtual int set_pool_size(uint){ return 0; }
virtual int set_idle_timeout(uint){ return 0; }
virtual int set_oversubscribe(uint){ return 0; }
virtual int set_stall_limit(uint){ return 0; }
virtual int get_thread_count() { return tp_stats.num_worker_threads; }
virtual int get_idle_thread_count(){ return 0; }
virtual void resume(TP_connection* c)=0;
};
#ifdef _WIN32
struct TP_pool_win:TP_pool
{
TP_pool_win();
int init() override;
~TP_pool_win() override;
TP_connection *new_connection(CONNECT *c) override;
void add(TP_connection *) override;
int set_max_threads(uint) override;
int set_min_threads(uint) override;
void resume(TP_connection *c) override;
};
#endif
struct TP_pool_generic :TP_pool
{
TP_pool_generic();
~TP_pool_generic();
int init() override;
TP_connection *new_connection(CONNECT *c) override;
void add(TP_connection *) override;
int set_pool_size(uint) override;
int set_stall_limit(uint) override;
int get_idle_thread_count() override;
void resume(TP_connection* c) override;
};
#endif /* HAVE_POOL_OF_THREADS */
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