libeio/etp.c

/*
 * libetp implementation
 *
 * Copyright (c) 2007,2008,2009,2010,2011,2012,2013,2015 Marc Alexander Lehmann <libetp@schmorp.de>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modifica-
 * tion, are permitted provided that the following conditions are met:
 *
 *   1.  Redistributions of source code must retain the above copyright notice,
 *       this list of conditions and the following disclaimer.
 *
 *   2.  Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-
 * CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO
 * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-
 * CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH-
 * ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * Alternatively, the contents of this file may be used under the terms of
 * the GNU General Public License ("GPL") version 2 or any later version,
 * in which case the provisions of the GPL are applicable instead of
 * the above. If you wish to allow the use of your version of this file
 * only under the terms of the GPL and not to allow others to use your
 * version of this file under the BSD license, indicate your decision
 * by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL. If you do not delete the
 * provisions above, a recipient may use your version of this file under
 * either the BSD or the GPL.
 */

#if HAVE_SYS_PRCTL_H
# include <sys/prctl.h>
#endif

#ifndef ETP_API_DECL
# define ETP_API_DECL static
#endif

#ifndef ETP_PRI_MIN
# define ETP_PRI_MIN 0
# define ETP_PRI_MAX 0
#endif

#ifndef ETP_TYPE_QUIT
# define ETP_TYPE_QUIT 0
#endif

#ifndef ETP_TYPE_GROUP
# define ETP_TYPE_GROUP 1
#endif

#ifndef ETP_WANT_POLL
# define ETP_WANT_POLL(pool) pool->want_poll_cb (pool->userdata)
#endif
#ifndef ETP_DONE_POLL
# define ETP_DONE_POLL(pool) pool->done_poll_cb (pool->userdata)
#endif

#define ETP_NUM_PRI (ETP_PRI_MAX - ETP_PRI_MIN + 1)

#define ETP_TICKS ((1000000 + 1023) >> 10)

enum {
  ETP_FLAG_GROUPADD = 0x04, /* some request was added to the group */
  ETP_FLAG_DELAYED  = 0x08, /* groiup request has been delayed */
};

/* calculate time difference in ~1/ETP_TICKS of a second */
ecb_inline int
etp_tvdiff (struct timeval *tv1, struct timeval *tv2)
{
  return  (tv2->tv_sec  - tv1->tv_sec ) * ETP_TICKS
       + ((tv2->tv_usec - tv1->tv_usec) >> 10);
}

struct etp_tmpbuf
{
  void *ptr;
  int len;
};

static void *
etp_tmpbuf_get (struct etp_tmpbuf *buf, int len)
{
  if (buf->len < len)
    {
      free (buf->ptr);
      buf->ptr = malloc (buf->len = len);
    }

  return buf->ptr;
}

/*
 * a somewhat faster data structure might be nice, but
 * with 8 priorities this actually needs <20 insns
 * per shift, the most expensive operation.
 */
typedef struct
{
  ETP_REQ *qs[ETP_NUM_PRI], *qe[ETP_NUM_PRI]; /* qstart, qend */
  int size;
} etp_reqq;

typedef struct etp_pool *etp_pool;

typedef struct etp_worker
{
  etp_pool pool;

  struct etp_tmpbuf tmpbuf;

  /* locked by pool->wrklock */
  struct etp_worker *prev, *next;

  xthread_t tid;

#ifdef ETP_WORKER_COMMON
  ETP_WORKER_COMMON
#endif
} etp_worker;

struct etp_pool
{
   void *userdata;

   etp_reqq req_queue;
   etp_reqq res_queue;

   unsigned int started, idle, wanted;

   unsigned int max_poll_time;     /* pool->reslock */
   unsigned int max_poll_reqs;     /* pool->reslock */

   unsigned int nreqs;    /* pool->reqlock */
   unsigned int nready;   /* pool->reqlock */
   unsigned int npending; /* pool->reqlock */
   unsigned int max_idle;      /* maximum number of threads that can pool->idle indefinitely */
   unsigned int idle_timeout; /* number of seconds after which an pool->idle threads exit */

   void (*want_poll_cb) (void *userdata);
   void (*done_poll_cb) (void *userdata);
 
   xmutex_t wrklock;
   xmutex_t reslock;
   xmutex_t reqlock;
   xcond_t  reqwait;

   etp_worker wrk_first;
};

#define ETP_WORKER_LOCK(wrk)   X_LOCK   (pool->wrklock)
#define ETP_WORKER_UNLOCK(wrk) X_UNLOCK (pool->wrklock)

/* worker threads management */

static void
etp_worker_clear (etp_worker *wrk)
{
}

static void ecb_cold
etp_worker_free (etp_worker *wrk)
{
  free (wrk->tmpbuf.ptr);

  wrk->next->prev = wrk->prev;
  wrk->prev->next = wrk->next;

  free (wrk);
}

ETP_API_DECL unsigned int
etp_nreqs (etp_pool pool)
{
  int retval;
  if (WORDACCESS_UNSAFE) X_LOCK   (pool->reqlock);
  retval = pool->nreqs;
  if (WORDACCESS_UNSAFE) X_UNLOCK (pool->reqlock);
  return retval;
}

ETP_API_DECL unsigned int
etp_nready (etp_pool pool)
{
  unsigned int retval;

  if (WORDACCESS_UNSAFE) X_LOCK   (pool->reqlock);
  retval = pool->nready;
  if (WORDACCESS_UNSAFE) X_UNLOCK (pool->reqlock);

  return retval;
}

ETP_API_DECL unsigned int
etp_npending (etp_pool pool)
{
  unsigned int retval;

  if (WORDACCESS_UNSAFE) X_LOCK   (pool->reqlock);
  retval = pool->npending;
  if (WORDACCESS_UNSAFE) X_UNLOCK (pool->reqlock);

  return retval;
}

ETP_API_DECL unsigned int
etp_nthreads (etp_pool pool)
{
  unsigned int retval;

  if (WORDACCESS_UNSAFE) X_LOCK   (pool->reqlock);
  retval = pool->started;
  if (WORDACCESS_UNSAFE) X_UNLOCK (pool->reqlock);

  return retval;
}

static void ecb_noinline ecb_cold
reqq_init (etp_reqq *q)
{
  int pri;

  for (pri = 0; pri < ETP_NUM_PRI; ++pri)
    q->qs[pri] = q->qe[pri] = 0;

  q->size = 0;
}

static int ecb_noinline
reqq_push (etp_reqq *q, ETP_REQ *req)
{
  int pri = req->pri;
  req->next = 0;

  if (q->qe[pri])
    {
      q->qe[pri]->next = req;
      q->qe[pri] = req;
    }
  else
    q->qe[pri] = q->qs[pri] = req;

  return q->size++;
}

static ETP_REQ * ecb_noinline
reqq_shift (etp_reqq *q)
{
  int pri;

  if (!q->size)
    return 0;

  --q->size;

  for (pri = ETP_NUM_PRI; pri--; )
    {
      ETP_REQ *req = q->qs[pri];

      if (req)
        {
          if (!(q->qs[pri] = (ETP_REQ *)req->next))
            q->qe[pri] = 0;

          return req;
        }
    }

  abort ();
}

ETP_API_DECL int ecb_cold
etp_init (etp_pool pool, void *userdata, void (*want_poll)(void *userdata), void (*done_poll)(void *userdata))
{
  X_MUTEX_CREATE (pool->wrklock);
  X_MUTEX_CREATE (pool->reslock);
  X_MUTEX_CREATE (pool->reqlock);
  X_COND_CREATE  (pool->reqwait);

  reqq_init (&pool->req_queue);
  reqq_init (&pool->res_queue);

  pool->wrk_first.next =
  pool->wrk_first.prev = &pool->wrk_first;

  pool->started  = 0;
  pool->idle     = 0;
  pool->nreqs    = 0;
  pool->nready   = 0;
  pool->npending = 0;
  pool->wanted   = 4;

  pool->max_idle = 4;      /* maximum number of threads that can pool->idle indefinitely */
  pool->idle_timeout = 10; /* number of seconds after which an pool->idle threads exit */

  pool->userdata     = userdata;
  pool->want_poll_cb = want_poll;
  pool->done_poll_cb = done_poll;

  return 0;
}

static void ecb_noinline ecb_cold
etp_proc_init (void)
{
#if HAVE_PRCTL_SET_NAME
  /* provide a more sensible "thread name" */
  char name[16 + 1];
  const int namelen = sizeof (name) - 1;
  int len;

  prctl (PR_GET_NAME, (unsigned long)name, 0, 0, 0);
  name [namelen] = 0;
  len = strlen (name);
  strcpy (name + (len <= namelen - 4 ? len : namelen - 4), "/eio");
  prctl (PR_SET_NAME, (unsigned long)name, 0, 0, 0);
#endif
}

X_THREAD_PROC (etp_proc)
{
  ETP_REQ *req;
  struct timespec ts;
  etp_worker *self = (etp_worker *)thr_arg;
  etp_pool pool = self->pool;

  etp_proc_init ();

  /* try to distribute timeouts somewhat evenly */
  ts.tv_nsec = ((unsigned long)self & 1023UL) * (1000000000UL / 1024UL);

  for (;;)
    {
      ts.tv_sec = 0;

      X_LOCK (pool->reqlock);

      for (;;)
        {
          req = reqq_shift (&pool->req_queue);

          if (ecb_expect_true (req))
            break;

          if (ts.tv_sec == 1) /* no request, but timeout detected, let's quit */
            {
              X_UNLOCK (pool->reqlock);
              X_LOCK (pool->wrklock);
              --pool->started;
              X_UNLOCK (pool->wrklock);
              goto quit;
            }

          ++pool->idle;

          if (pool->idle <= pool->max_idle)
            /* we are allowed to pool->idle, so do so without any timeout */
            X_COND_WAIT (pool->reqwait, pool->reqlock);
          else
            {
              /* initialise timeout once */
              if (!ts.tv_sec)
                ts.tv_sec = time (0) + pool->idle_timeout;

              if (X_COND_TIMEDWAIT (pool->reqwait, pool->reqlock, ts) == ETIMEDOUT)
                ts.tv_sec = 1; /* assuming this is not a value computed above.,.. */
            }

          --pool->idle;
        }

      --pool->nready;

      X_UNLOCK (pool->reqlock);
     
      if (ecb_expect_false (req->type == ETP_TYPE_QUIT))
        goto quit;

      ETP_EXECUTE (self, req);

      X_LOCK (pool->reslock);

      ++pool->npending;

      if (!reqq_push (&pool->res_queue, req))
        ETP_WANT_POLL (pool);

      etp_worker_clear (self);

      X_UNLOCK (pool->reslock);
    }

quit:
  free (req);

  X_LOCK (pool->wrklock);
  etp_worker_free (self);
  X_UNLOCK (pool->wrklock);

  return 0;
}

static void ecb_cold
etp_start_thread (etp_pool pool)
{
  etp_worker *wrk = calloc (1, sizeof (etp_worker));

  /*TODO*/
  assert (("unable to allocate worker thread data", wrk));

  wrk->pool = pool;

  X_LOCK (pool->wrklock);

  if (xthread_create (&wrk->tid, etp_proc, (void *)wrk))
    {
      wrk->prev = &pool->wrk_first;
      wrk->next = pool->wrk_first.next;
      pool->wrk_first.next->prev = wrk;
      pool->wrk_first.next = wrk;
      ++pool->started;
    }
  else
    free (wrk);

  X_UNLOCK (pool->wrklock);
}

static void
etp_maybe_start_thread (etp_pool pool)
{
  if (ecb_expect_true (etp_nthreads (pool) >= pool->wanted))
    return;
  
  /* todo: maybe use pool->idle here, but might be less exact */
  if (ecb_expect_true (0 <= (int)etp_nthreads (pool) + (int)etp_npending (pool) - (int)etp_nreqs (pool)))
    return;

  etp_start_thread (pool);
}

static void ecb_cold
etp_end_thread (etp_pool pool)
{
  ETP_REQ *req = calloc (1, sizeof (ETP_REQ)); /* will be freed by worker */

  req->type = ETP_TYPE_QUIT;
  req->pri  = ETP_PRI_MAX - ETP_PRI_MIN;

  X_LOCK (pool->reqlock);
  reqq_push (&pool->req_queue, req);
  X_COND_SIGNAL (pool->reqwait);
  X_UNLOCK (pool->reqlock);

  X_LOCK (pool->wrklock);
  --pool->started;
  X_UNLOCK (pool->wrklock);
}

ETP_API_DECL int
etp_poll (etp_pool pool)
{
  unsigned int maxreqs;
  unsigned int maxtime;
  struct timeval tv_start, tv_now;

  X_LOCK (pool->reslock);
  maxreqs = pool->max_poll_reqs;
  maxtime = pool->max_poll_time;
  X_UNLOCK (pool->reslock);

  if (maxtime)
    gettimeofday (&tv_start, 0);

  for (;;)
    {
      ETP_REQ *req;

      etp_maybe_start_thread (pool);

      X_LOCK (pool->reslock);
      req = reqq_shift (&pool->res_queue);

      if (ecb_expect_true (req))
        {
          --pool->npending;

          if (!pool->res_queue.size)
            ETP_DONE_POLL (pool);
        }

      X_UNLOCK (pool->reslock);

      if (ecb_expect_false (!req))
        return 0;

      X_LOCK (pool->reqlock);
      --pool->nreqs;
      X_UNLOCK (pool->reqlock);

      if (ecb_expect_false (req->type == ETP_TYPE_GROUP && req->size))
        {
          req->flags |= ETP_FLAG_DELAYED; /* mark request as delayed */
          continue;
        }
      else
        {
          int res = ETP_FINISH (req);
          if (ecb_expect_false (res))
            return res;
        }

      if (ecb_expect_false (maxreqs && !--maxreqs))
        break;

      if (maxtime)
        {
          gettimeofday (&tv_now, 0);

          if (etp_tvdiff (&tv_start, &tv_now) >= maxtime)
            break;
        }
    }

  errno = EAGAIN;
  return -1;
}

ETP_API_DECL void
etp_grp_cancel (etp_pool pool, ETP_REQ *grp);

ETP_API_DECL void
etp_cancel (etp_pool pool, ETP_REQ *req)
{
  req->cancelled = 1;

  etp_grp_cancel (pool, req);
}

ETP_API_DECL void
etp_grp_cancel (etp_pool pool, ETP_REQ *grp)
{
  for (grp = grp->grp_first; grp; grp = grp->grp_next)
    etp_cancel (pool, grp);
}

ETP_API_DECL void
etp_submit (etp_pool pool, ETP_REQ *req)
{
  req->pri -= ETP_PRI_MIN;

  if (ecb_expect_false (req->pri < ETP_PRI_MIN - ETP_PRI_MIN)) req->pri = ETP_PRI_MIN - ETP_PRI_MIN;
  if (ecb_expect_false (req->pri > ETP_PRI_MAX - ETP_PRI_MIN)) req->pri = ETP_PRI_MAX - ETP_PRI_MIN;

  if (ecb_expect_false (req->type == ETP_TYPE_GROUP))
    {
      /* I hope this is worth it :/ */
      X_LOCK (pool->reqlock);
      ++pool->nreqs;
      X_UNLOCK (pool->reqlock);

      X_LOCK (pool->reslock);

      ++pool->npending;

      if (!reqq_push (&pool->res_queue, req))
        ETP_WANT_POLL (pool);

      X_UNLOCK (pool->reslock);
    }
  else
    {
      X_LOCK (pool->reqlock);
      ++pool->nreqs;
      ++pool->nready;
      reqq_push (&pool->req_queue, req);
      X_COND_SIGNAL (pool->reqwait);
      X_UNLOCK (pool->reqlock);

      etp_maybe_start_thread (pool);
    }
}

ETP_API_DECL void ecb_cold
etp_set_max_poll_time (etp_pool pool, double seconds)
{
  if (WORDACCESS_UNSAFE) X_LOCK   (pool->reslock);
  pool->max_poll_time = seconds * ETP_TICKS;
  if (WORDACCESS_UNSAFE) X_UNLOCK (pool->reslock);
}

ETP_API_DECL void ecb_cold
etp_set_max_poll_reqs (etp_pool pool, unsigned int maxreqs)
{
  if (WORDACCESS_UNSAFE) X_LOCK   (pool->reslock);
  pool->max_poll_reqs = maxreqs;
  if (WORDACCESS_UNSAFE) X_UNLOCK (pool->reslock);
}

ETP_API_DECL void ecb_cold
etp_set_max_idle (etp_pool pool, unsigned int threads)
{
  if (WORDACCESS_UNSAFE) X_LOCK   (pool->reqlock);
  pool->max_idle = threads;
  if (WORDACCESS_UNSAFE) X_UNLOCK (pool->reqlock);
}

ETP_API_DECL void ecb_cold
etp_set_idle_timeout (etp_pool pool, unsigned int seconds)
{
  if (WORDACCESS_UNSAFE) X_LOCK   (pool->reqlock);
  pool->idle_timeout = seconds;
  if (WORDACCESS_UNSAFE) X_UNLOCK (pool->reqlock);
}

ETP_API_DECL void ecb_cold
etp_set_min_parallel (etp_pool pool, unsigned int threads)
{
  if (pool->wanted < threads)
    pool->wanted = threads;
}

ETP_API_DECL void ecb_cold
etp_set_max_parallel (etp_pool pool, unsigned int threads)
{
  if (pool->wanted > threads)
    pool->wanted = threads;

  while (pool->started > pool->wanted)
    etp_end_thread (pool);
}

Revision:	1.13
Committed:	Tue Aug 14 11:44:53 2018 UTC (5 years, 9 months ago) by root
Content type:	text/plain
Branch:	MAIN
Changes since 1.12:	+4 -0 lines
Log Message:	* empty log message *
#	User	Rev	Content
1	root	1.1	/*
2			* libetp implementation
3			*
4	root	1.9	* Copyright (c) 2007,2008,2009,2010,2011,2012,2013,2015 Marc Alexander Lehmann <libetp@schmorp.de>
5	root	1.1	* All rights reserved.
6			*
7			* Redistribution and use in source and binary forms, with or without modifica-
8			* tion, are permitted provided that the following conditions are met:
9			*
10			* 1. Redistributions of source code must retain the above copyright notice,
11			* this list of conditions and the following disclaimer.
12			*
13			* 2. Redistributions in binary form must reproduce the above copyright
14			* notice, this list of conditions and the following disclaimer in the
15			* documentation and/or other materials provided with the distribution.
16			*
17			* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
18			* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-
19			* CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
20			* EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-
21			* CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
22			* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
23			* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
24			* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH-
25			* ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
26			* OF THE POSSIBILITY OF SUCH DAMAGE.
27			*
28			* Alternatively, the contents of this file may be used under the terms of
29			* the GNU General Public License ("GPL") version 2 or any later version,
30			* in which case the provisions of the GPL are applicable instead of
31			* the above. If you wish to allow the use of your version of this file
32			* only under the terms of the GPL and not to allow others to use your
33			* version of this file under the BSD license, indicate your decision
34			* by deleting the provisions above and replace them with the notice
35			* and other provisions required by the GPL. If you do not delete the
36			* provisions above, a recipient may use your version of this file under
37			* either the BSD or the GPL.
38			*/
39
40	root	1.13	#if HAVE_SYS_PRCTL_H
41			# include <sys/prctl.h>
42			#endif
43
44	root	1.1	#ifndef ETP_API_DECL
45			# define ETP_API_DECL static
46			#endif
47
48			#ifndef ETP_PRI_MIN
49			# define ETP_PRI_MIN 0
50			# define ETP_PRI_MAX 0
51			#endif
52
53			#ifndef ETP_TYPE_QUIT
54			# define ETP_TYPE_QUIT 0
55			#endif
56
57			#ifndef ETP_TYPE_GROUP
58			# define ETP_TYPE_GROUP 1
59			#endif
60
61	root	1.6	#ifndef ETP_WANT_POLL
62			# define ETP_WANT_POLL(pool) pool->want_poll_cb (pool->userdata)
63			#endif
64			#ifndef ETP_DONE_POLL
65			# define ETP_DONE_POLL(pool) pool->done_poll_cb (pool->userdata)
66			#endif
67
68	root	1.1	#define ETP_NUM_PRI (ETP_PRI_MAX - ETP_PRI_MIN + 1)
69
70			#define ETP_TICKS ((1000000 + 1023) >> 10)
71
72	root	1.4	enum {
73			ETP_FLAG_GROUPADD = 0x04, /* some request was added to the group */
74			ETP_FLAG_DELAYED = 0x08, /* groiup request has been delayed */
75			};
76
77	root	1.1	/* calculate time difference in ~1/ETP_TICKS of a second */
78			ecb_inline int
79			etp_tvdiff (struct timeval tv1, struct timeval tv2)
80			{
81			return (tv2->tv_sec - tv1->tv_sec ) * ETP_TICKS
82			+ ((tv2->tv_usec - tv1->tv_usec) >> 10);
83			}
84
85	root	1.3	struct etp_tmpbuf
86			{
87			void *ptr;
88			int len;
89			};
90
91			static void *
92			etp_tmpbuf_get (struct etp_tmpbuf *buf, int len)
93			{
94			if (buf->len < len)
95			{
96			free (buf->ptr);
97			buf->ptr = malloc (buf->len = len);
98			}
99
100			return buf->ptr;
101			}
102
103	root	1.5	/*
104			* a somewhat faster data structure might be nice, but
105			* with 8 priorities this actually needs <20 insns
106			* per shift, the most expensive operation.
107			*/
108			typedef struct
109			{
110			ETP_REQ qs[ETP_NUM_PRI], qe[ETP_NUM_PRI]; /* qstart, qend */
111			int size;
112			} etp_reqq;
113
114	root	1.8	typedef struct etp_pool *etp_pool;
115
116			typedef struct etp_worker
117			{
118			etp_pool pool;
119
120			struct etp_tmpbuf tmpbuf;
121
122			/* locked by pool->wrklock */
123			struct etp_worker prev, next;
124
125			xthread_t tid;
126
127			#ifdef ETP_WORKER_COMMON
128			ETP_WORKER_COMMON
129			#endif
130			} etp_worker;
131
132	root	1.5	struct etp_pool
133			{
134	root	1.6	void *userdata;
135
136	root	1.5	etp_reqq req_queue;
137			etp_reqq res_queue;
138	root	1.6
139			unsigned int started, idle, wanted;
140
141			unsigned int max_poll_time; /* pool->reslock */
142			unsigned int max_poll_reqs; /* pool->reslock */
143
144			unsigned int nreqs; /* pool->reqlock */
145			unsigned int nready; /* pool->reqlock */
146			unsigned int npending; /* pool->reqlock */
147			unsigned int max_idle; /* maximum number of threads that can pool->idle indefinitely */
148			unsigned int idle_timeout; /* number of seconds after which an pool->idle threads exit */
149
150			void (want_poll_cb) (void userdata);
151			void (done_poll_cb) (void userdata);
152
153			xmutex_t wrklock;
154			xmutex_t reslock;
155			xmutex_t reqlock;
156			xcond_t reqwait;
157	root	1.7
158			etp_worker wrk_first;
159	root	1.5	};
160
161	root	1.6	#define ETP_WORKER_LOCK(wrk) X_LOCK (pool->wrklock)
162			#define ETP_WORKER_UNLOCK(wrk) X_UNLOCK (pool->wrklock)
163	root	1.1
164			/* worker threads management */
165
166			static void
167			etp_worker_clear (etp_worker *wrk)
168			{
169			}
170
171			static void ecb_cold
172			etp_worker_free (etp_worker *wrk)
173			{
174			free (wrk->tmpbuf.ptr);
175
176			wrk->next->prev = wrk->prev;
177			wrk->prev->next = wrk->next;
178
179			free (wrk);
180			}
181
182			ETP_API_DECL unsigned int
183	root	1.5	etp_nreqs (etp_pool pool)
184	root	1.1	{
185			int retval;
186	root	1.6	if (WORDACCESS_UNSAFE) X_LOCK (pool->reqlock);
187			retval = pool->nreqs;
188			if (WORDACCESS_UNSAFE) X_UNLOCK (pool->reqlock);
189	root	1.1	return retval;
190			}
191
192			ETP_API_DECL unsigned int
193	root	1.5	etp_nready (etp_pool pool)
194	root	1.1	{
195			unsigned int retval;
196
197	root	1.6	if (WORDACCESS_UNSAFE) X_LOCK (pool->reqlock);
198			retval = pool->nready;
199			if (WORDACCESS_UNSAFE) X_UNLOCK (pool->reqlock);
200	root	1.1
201			return retval;
202			}
203
204			ETP_API_DECL unsigned int
205	root	1.5	etp_npending (etp_pool pool)
206	root	1.1	{
207			unsigned int retval;
208
209	root	1.6	if (WORDACCESS_UNSAFE) X_LOCK (pool->reqlock);
210			retval = pool->npending;
211			if (WORDACCESS_UNSAFE) X_UNLOCK (pool->reqlock);
212	root	1.1
213			return retval;
214			}
215
216			ETP_API_DECL unsigned int
217	root	1.5	etp_nthreads (etp_pool pool)
218	root	1.1	{
219			unsigned int retval;
220
221	root	1.6	if (WORDACCESS_UNSAFE) X_LOCK (pool->reqlock);
222			retval = pool->started;
223			if (WORDACCESS_UNSAFE) X_UNLOCK (pool->reqlock);
224	root	1.1
225			return retval;
226			}
227
228			static void ecb_noinline ecb_cold
229			reqq_init (etp_reqq *q)
230			{
231			int pri;
232
233			for (pri = 0; pri < ETP_NUM_PRI; ++pri)
234			q->qs[pri] = q->qe[pri] = 0;
235
236			q->size = 0;
237			}
238
239			static int ecb_noinline
240			reqq_push (etp_reqq q, ETP_REQ req)
241			{
242			int pri = req->pri;
243			req->next = 0;
244
245			if (q->qe[pri])
246			{
247			q->qe[pri]->next = req;
248			q->qe[pri] = req;
249			}
250			else
251			q->qe[pri] = q->qs[pri] = req;
252
253			return q->size++;
254			}
255
256			static ETP_REQ * ecb_noinline
257			reqq_shift (etp_reqq *q)
258			{
259			int pri;
260
261			if (!q->size)
262			return 0;
263
264			--q->size;
265
266			for (pri = ETP_NUM_PRI; pri--; )
267			{
268	root	1.2	ETP_REQ *req = q->qs[pri];
269	root	1.1
270			if (req)
271			{
272	root	1.2	if (!(q->qs[pri] = (ETP_REQ *)req->next))
273	root	1.1	q->qe[pri] = 0;
274
275			return req;
276			}
277			}
278
279			abort ();
280			}
281
282			ETP_API_DECL int ecb_cold
283	root	1.7	etp_init (etp_pool pool, void userdata, void (want_poll)(void userdata), void (done_poll)(void *userdata))
284	root	1.1	{
285	root	1.6	X_MUTEX_CREATE (pool->wrklock);
286			X_MUTEX_CREATE (pool->reslock);
287			X_MUTEX_CREATE (pool->reqlock);
288			X_COND_CREATE (pool->reqwait);
289	root	1.1
290	root	1.5	reqq_init (&pool->req_queue);
291			reqq_init (&pool->res_queue);
292	root	1.1
293	root	1.7	pool->wrk_first.next =
294			pool->wrk_first.prev = &pool->wrk_first;
295	root	1.1
296	root	1.6	pool->started = 0;
297			pool->idle = 0;
298			pool->nreqs = 0;
299			pool->nready = 0;
300			pool->npending = 0;
301			pool->wanted = 4;
302
303			pool->max_idle = 4; /* maximum number of threads that can pool->idle indefinitely */
304			pool->idle_timeout = 10; /* number of seconds after which an pool->idle threads exit */
305	root	1.1
306	root	1.7	pool->userdata = userdata;
307	root	1.6	pool->want_poll_cb = want_poll;
308			pool->done_poll_cb = done_poll;
309	root	1.1
310			return 0;
311			}
312
313	root	1.4	static void ecb_noinline ecb_cold
314			etp_proc_init (void)
315			{
316			#if HAVE_PRCTL_SET_NAME
317			/* provide a more sensible "thread name" */
318	root	1.12	char name[16 + 1];
319	root	1.4	const int namelen = sizeof (name) - 1;
320			int len;
321
322			prctl (PR_GET_NAME, (unsigned long)name, 0, 0, 0);
323			name [namelen] = 0;
324			len = strlen (name);
325			strcpy (name + (len <= namelen - 4 ? len : namelen - 4), "/eio");
326			prctl (PR_SET_NAME, (unsigned long)name, 0, 0, 0);
327			#endif
328			}
329
330			X_THREAD_PROC (etp_proc)
331			{
332			ETP_REQ *req;
333			struct timespec ts;
334			etp_worker self = (etp_worker )thr_arg;
335	root	1.5	etp_pool pool = self->pool;
336	root	1.4
337			etp_proc_init ();
338
339			/* try to distribute timeouts somewhat evenly */
340			ts.tv_nsec = ((unsigned long)self & 1023UL) * (1000000000UL / 1024UL);
341
342			for (;;)
343			{
344			ts.tv_sec = 0;
345
346	root	1.6	X_LOCK (pool->reqlock);
347	root	1.4
348			for (;;)
349			{
350	root	1.5	req = reqq_shift (&pool->req_queue);
351	root	1.4
352	root	1.9	if (ecb_expect_true (req))
353	root	1.4	break;
354
355			if (ts.tv_sec == 1) /* no request, but timeout detected, let's quit */
356			{
357	root	1.6	X_UNLOCK (pool->reqlock);
358			X_LOCK (pool->wrklock);
359			--pool->started;
360			X_UNLOCK (pool->wrklock);
361	root	1.4	goto quit;
362			}
363
364	root	1.6	++pool->idle;
365	root	1.4
366	root	1.6	if (pool->idle <= pool->max_idle)
367			/* we are allowed to pool->idle, so do so without any timeout */
368			X_COND_WAIT (pool->reqwait, pool->reqlock);
369	root	1.4	else
370			{
371			/* initialise timeout once */
372			if (!ts.tv_sec)
373	root	1.6	ts.tv_sec = time (0) + pool->idle_timeout;
374	root	1.4
375	root	1.6	if (X_COND_TIMEDWAIT (pool->reqwait, pool->reqlock, ts) == ETIMEDOUT)
376	root	1.4	ts.tv_sec = 1; /* assuming this is not a value computed above.,.. */
377			}
378
379	root	1.6	--pool->idle;
380	root	1.4	}
381
382	root	1.6	--pool->nready;
383	root	1.4
384	root	1.6	X_UNLOCK (pool->reqlock);
385	root	1.4
386	root	1.9	if (ecb_expect_false (req->type == ETP_TYPE_QUIT))
387	root	1.4	goto quit;
388
389			ETP_EXECUTE (self, req);
390
391	root	1.6	X_LOCK (pool->reslock);
392	root	1.4
393	root	1.6	++pool->npending;
394	root	1.4
395	root	1.6	if (!reqq_push (&pool->res_queue, req))
396	root	1.9	ETP_WANT_POLL (pool);
397	root	1.4
398			etp_worker_clear (self);
399
400	root	1.6	X_UNLOCK (pool->reslock);
401	root	1.4	}
402
403			quit:
404			free (req);
405
406	root	1.6	X_LOCK (pool->wrklock);
407	root	1.4	etp_worker_free (self);
408	root	1.6	X_UNLOCK (pool->wrklock);
409	root	1.4
410			return 0;
411			}
412	root	1.1
413			static void ecb_cold
414	root	1.5	etp_start_thread (etp_pool pool)
415	root	1.1	{
416			etp_worker *wrk = calloc (1, sizeof (etp_worker));
417
418			/TODO/
419			assert (("unable to allocate worker thread data", wrk));
420
421	root	1.5	wrk->pool = pool;
422
423	root	1.6	X_LOCK (pool->wrklock);
424	root	1.1
425			if (xthread_create (&wrk->tid, etp_proc, (void *)wrk))
426			{
427	root	1.8	wrk->prev = &pool->wrk_first;
428	root	1.7	wrk->next = pool->wrk_first.next;
429			pool->wrk_first.next->prev = wrk;
430			pool->wrk_first.next = wrk;
431	root	1.6	++pool->started;
432	root	1.1	}
433			else
434			free (wrk);
435
436	root	1.6	X_UNLOCK (pool->wrklock);
437	root	1.1	}
438
439			static void
440	root	1.5	etp_maybe_start_thread (etp_pool pool)
441	root	1.1	{
442	root	1.6	if (ecb_expect_true (etp_nthreads (pool) >= pool->wanted))
443	root	1.1	return;
444
445	root	1.6	/* todo: maybe use pool->idle here, but might be less exact */
446	root	1.5	if (ecb_expect_true (0 <= (int)etp_nthreads (pool) + (int)etp_npending (pool) - (int)etp_nreqs (pool)))
447	root	1.1	return;
448
449	root	1.5	etp_start_thread (pool);
450	root	1.1	}
451
452			static void ecb_cold
453	root	1.5	etp_end_thread (etp_pool pool)
454	root	1.1	{
455	root	1.2	ETP_REQ req = calloc (1, sizeof (ETP_REQ)); / will be freed by worker */
456	root	1.1
457			req->type = ETP_TYPE_QUIT;
458			req->pri = ETP_PRI_MAX - ETP_PRI_MIN;
459
460	root	1.6	X_LOCK (pool->reqlock);
461	root	1.5	reqq_push (&pool->req_queue, req);
462	root	1.6	X_COND_SIGNAL (pool->reqwait);
463			X_UNLOCK (pool->reqlock);
464	root	1.1
465	root	1.6	X_LOCK (pool->wrklock);
466			--pool->started;
467			X_UNLOCK (pool->wrklock);
468	root	1.1	}
469
470			ETP_API_DECL int
471	root	1.5	etp_poll (etp_pool pool)
472	root	1.1	{
473			unsigned int maxreqs;
474			unsigned int maxtime;
475			struct timeval tv_start, tv_now;
476
477	root	1.6	X_LOCK (pool->reslock);
478			maxreqs = pool->max_poll_reqs;
479			maxtime = pool->max_poll_time;
480			X_UNLOCK (pool->reslock);
481	root	1.1
482			if (maxtime)
483			gettimeofday (&tv_start, 0);
484
485			for (;;)
486			{
487			ETP_REQ *req;
488
489	root	1.5	etp_maybe_start_thread (pool);
490	root	1.1
491	root	1.6	X_LOCK (pool->reslock);
492	root	1.5	req = reqq_shift (&pool->res_queue);
493	root	1.1
494	root	1.9	if (ecb_expect_true (req))
495	root	1.1	{
496	root	1.6	--pool->npending;
497	root	1.1
498	root	1.6	if (!pool->res_queue.size)
499	root	1.9	ETP_DONE_POLL (pool);
500	root	1.1	}
501
502	root	1.6	X_UNLOCK (pool->reslock);
503	root	1.1
504	root	1.9	if (ecb_expect_false (!req))
505	root	1.1	return 0;
506
507	root	1.6	X_LOCK (pool->reqlock);
508			--pool->nreqs;
509			X_UNLOCK (pool->reqlock);
510	root	1.1
511			if (ecb_expect_false (req->type == ETP_TYPE_GROUP && req->size))
512			{
513	root	1.4	req->flags \|= ETP_FLAG_DELAYED; /* mark request as delayed */
514	root	1.1	continue;
515			}
516			else
517			{
518			int res = ETP_FINISH (req);
519			if (ecb_expect_false (res))
520			return res;
521			}
522
523			if (ecb_expect_false (maxreqs && !--maxreqs))
524			break;
525
526			if (maxtime)
527			{
528			gettimeofday (&tv_now, 0);
529
530			if (etp_tvdiff (&tv_start, &tv_now) >= maxtime)
531			break;
532			}
533			}
534
535			errno = EAGAIN;
536			return -1;
537			}
538
539			ETP_API_DECL void
540	root	1.5	etp_grp_cancel (etp_pool pool, ETP_REQ *grp);
541	root	1.1
542			ETP_API_DECL void
543	root	1.5	etp_cancel (etp_pool pool, ETP_REQ *req)
544	root	1.1	{
545			req->cancelled = 1;
546
547	root	1.5	etp_grp_cancel (pool, req);
548	root	1.1	}
549
550			ETP_API_DECL void
551	root	1.5	etp_grp_cancel (etp_pool pool, ETP_REQ *grp)
552	root	1.1	{
553			for (grp = grp->grp_first; grp; grp = grp->grp_next)
554	root	1.5	etp_cancel (pool, grp);
555	root	1.1	}
556
557			ETP_API_DECL void
558	root	1.5	etp_submit (etp_pool pool, ETP_REQ *req)
559	root	1.1	{
560			req->pri -= ETP_PRI_MIN;
561
562			if (ecb_expect_false (req->pri < ETP_PRI_MIN - ETP_PRI_MIN)) req->pri = ETP_PRI_MIN - ETP_PRI_MIN;
563			if (ecb_expect_false (req->pri > ETP_PRI_MAX - ETP_PRI_MIN)) req->pri = ETP_PRI_MAX - ETP_PRI_MIN;
564
565			if (ecb_expect_false (req->type == ETP_TYPE_GROUP))
566			{
567			/* I hope this is worth it :/ */
568	root	1.6	X_LOCK (pool->reqlock);
569			++pool->nreqs;
570			X_UNLOCK (pool->reqlock);
571	root	1.1
572	root	1.6	X_LOCK (pool->reslock);
573	root	1.1
574	root	1.6	++pool->npending;
575	root	1.1
576	root	1.6	if (!reqq_push (&pool->res_queue, req))
577			ETP_WANT_POLL (pool);
578	root	1.1
579	root	1.6	X_UNLOCK (pool->reslock);
580	root	1.1	}
581			else
582			{
583	root	1.6	X_LOCK (pool->reqlock);
584			++pool->nreqs;
585			++pool->nready;
586	root	1.5	reqq_push (&pool->req_queue, req);
587	root	1.6	X_COND_SIGNAL (pool->reqwait);
588			X_UNLOCK (pool->reqlock);
589	root	1.1
590	root	1.5	etp_maybe_start_thread (pool);
591	root	1.1	}
592			}
593
594			ETP_API_DECL void ecb_cold
595	root	1.10	etp_set_max_poll_time (etp_pool pool, double seconds)
596	root	1.1	{
597	root	1.6	if (WORDACCESS_UNSAFE) X_LOCK (pool->reslock);
598	root	1.10	pool->max_poll_time = seconds * ETP_TICKS;
599	root	1.6	if (WORDACCESS_UNSAFE) X_UNLOCK (pool->reslock);
600	root	1.1	}
601
602			ETP_API_DECL void ecb_cold
603	root	1.5	etp_set_max_poll_reqs (etp_pool pool, unsigned int maxreqs)
604	root	1.1	{
605	root	1.6	if (WORDACCESS_UNSAFE) X_LOCK (pool->reslock);
606			pool->max_poll_reqs = maxreqs;
607			if (WORDACCESS_UNSAFE) X_UNLOCK (pool->reslock);
608	root	1.1	}
609
610			ETP_API_DECL void ecb_cold
611	root	1.10	etp_set_max_idle (etp_pool pool, unsigned int threads)
612	root	1.1	{
613	root	1.6	if (WORDACCESS_UNSAFE) X_LOCK (pool->reqlock);
614	root	1.10	pool->max_idle = threads;
615	root	1.6	if (WORDACCESS_UNSAFE) X_UNLOCK (pool->reqlock);
616	root	1.1	}
617
618			ETP_API_DECL void ecb_cold
619	root	1.5	etp_set_idle_timeout (etp_pool pool, unsigned int seconds)
620	root	1.1	{
621	root	1.6	if (WORDACCESS_UNSAFE) X_LOCK (pool->reqlock);
622			pool->idle_timeout = seconds;
623			if (WORDACCESS_UNSAFE) X_UNLOCK (pool->reqlock);
624	root	1.1	}
625
626			ETP_API_DECL void ecb_cold
627	root	1.10	etp_set_min_parallel (etp_pool pool, unsigned int threads)
628	root	1.1	{
629	root	1.10	if (pool->wanted < threads)
630			pool->wanted = threads;
631	root	1.1	}
632
633			ETP_API_DECL void ecb_cold
634	root	1.10	etp_set_max_parallel (etp_pool pool, unsigned int threads)
635	root	1.1	{
636	root	1.10	if (pool->wanted > threads)
637			pool->wanted = threads;
638	root	1.1
639	root	1.6	while (pool->started > pool->wanted)
640	root	1.5	etp_end_thread (pool);
641	root	1.1	}
642