libeio/etp.c

/*
 * libetp implementation
 *
 * Copyright (c) 2007,2008,2009,2010,2011,2012,2013 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.
 */

#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

#define ETP_NUM_PRI (ETP_PRI_MAX - ETP_PRI_MIN + 1)

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

/* 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);
}

static unsigned int started, idle, wanted = 4;

static void (*want_poll_cb) (void);
static void (*done_poll_cb) (void);
 
static unsigned int max_poll_time;     /* reslock */
static unsigned int max_poll_reqs;     /* reslock */

static unsigned int nreqs;    /* reqlock */
static unsigned int nready;   /* reqlock */
static unsigned int npending; /* reqlock */
static unsigned int max_idle = 4;      /* maximum number of threads that can idle indefinitely */
static unsigned int idle_timeout = 10; /* number of seconds after which an idle threads exit */

static xmutex_t wrklock;
static xmutex_t reslock;
static xmutex_t reqlock;
static xcond_t  reqwait;

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;
}

typedef struct etp_worker
{
  struct etp_tmpbuf tmpbuf;

  /* locked by wrklock */
  struct etp_worker *prev, *next;

  xthread_t tid;

#ifdef ETP_WORKER_COMMON
  ETP_WORKER_COMMON
#endif
} etp_worker;

static etp_worker wrk_first; /* NOT etp */

#define ETP_WORKER_LOCK(wrk)   X_LOCK   (wrklock)
#define ETP_WORKER_UNLOCK(wrk) X_UNLOCK (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 (void)
{
  int retval;
  if (WORDACCESS_UNSAFE) X_LOCK   (reqlock);
  retval = nreqs;
  if (WORDACCESS_UNSAFE) X_UNLOCK (reqlock);
  return retval;
}

ETP_API_DECL unsigned int
etp_nready (void)
{
  unsigned int retval;

  if (WORDACCESS_UNSAFE) X_LOCK   (reqlock);
  retval = nready;
  if (WORDACCESS_UNSAFE) X_UNLOCK (reqlock);

  return retval;
}

ETP_API_DECL unsigned int
etp_npending (void)
{
  unsigned int retval;

  if (WORDACCESS_UNSAFE) X_LOCK   (reqlock);
  retval = npending;
  if (WORDACCESS_UNSAFE) X_UNLOCK (reqlock);

  return retval;
}

ETP_API_DECL unsigned int
etp_nthreads (void)
{
  unsigned int retval;

  if (WORDACCESS_UNSAFE) X_LOCK   (reqlock);
  retval = started;
  if (WORDACCESS_UNSAFE) X_UNLOCK (reqlock);

  return retval;
}

/*
 * 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;

static etp_reqq req_queue;
static etp_reqq res_queue;

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 (void (*want_poll)(void), void (*done_poll)(void))
{
  X_MUTEX_CREATE (wrklock);
  X_MUTEX_CREATE (reslock);
  X_MUTEX_CREATE (reqlock);
  X_COND_CREATE  (reqwait);

  reqq_init (&req_queue);
  reqq_init (&res_queue);

  wrk_first.next =
  wrk_first.prev = &wrk_first;

  started  = 0;
  idle     = 0;
  nreqs    = 0;
  nready   = 0;
  npending = 0;

  want_poll_cb = want_poll;
  done_poll_cb = done_poll;

  return 0;
}

/* not yet in etp.c */
X_THREAD_PROC (etp_proc);

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

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

  X_LOCK (wrklock);

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

  X_UNLOCK (wrklock);
}

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

  etp_start_thread ();
}

static void ecb_cold
etp_end_thread (void)
{
  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 (reqlock);
  reqq_push (&req_queue, req);
  X_COND_SIGNAL (reqwait);
  X_UNLOCK (reqlock);

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

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

  X_LOCK (reslock);
  maxreqs = max_poll_reqs;
  maxtime = max_poll_time;
  X_UNLOCK (reslock);

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

  for (;;)
    {
      ETP_REQ *req;

      etp_maybe_start_thread ();

      X_LOCK (reslock);
      req = reqq_shift (&res_queue);

      if (req)
        {
          --npending;

          if (!res_queue.size && done_poll_cb)
            done_poll_cb ();
        }

      X_UNLOCK (reslock);

      if (!req)
        return 0;

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

      if (ecb_expect_false (req->type == ETP_TYPE_GROUP && req->size))
        {
          req->int1 = 1; /* 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_REQ *grp);

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

  etp_grp_cancel (req);
}

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

ETP_API_DECL void
etp_submit (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 (reqlock);
      ++nreqs;
      X_UNLOCK (reqlock);

      X_LOCK (reslock);

      ++npending;

      if (!reqq_push (&res_queue, req) && want_poll_cb)
        want_poll_cb ();

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

      etp_maybe_start_thread ();
    }
}

ETP_API_DECL void ecb_cold
etp_set_max_poll_time (double nseconds)
{
  if (WORDACCESS_UNSAFE) X_LOCK   (reslock);
  max_poll_time = nseconds * ETP_TICKS;
  if (WORDACCESS_UNSAFE) X_UNLOCK (reslock);
}

ETP_API_DECL void ecb_cold
etp_set_max_poll_reqs (unsigned int maxreqs)
{
  if (WORDACCESS_UNSAFE) X_LOCK   (reslock);
  max_poll_reqs = maxreqs;
  if (WORDACCESS_UNSAFE) X_UNLOCK (reslock);
}

ETP_API_DECL void ecb_cold
etp_set_max_idle (unsigned int nthreads)
{
  if (WORDACCESS_UNSAFE) X_LOCK   (reqlock);
  max_idle = nthreads;
  if (WORDACCESS_UNSAFE) X_UNLOCK (reqlock);
}

ETP_API_DECL void ecb_cold
etp_set_idle_timeout (unsigned int seconds)
{
  if (WORDACCESS_UNSAFE) X_LOCK   (reqlock);
  idle_timeout = seconds;
  if (WORDACCESS_UNSAFE) X_UNLOCK (reqlock);
}

ETP_API_DECL void ecb_cold
etp_set_min_parallel (unsigned int nthreads)
{
  if (wanted < nthreads)
    wanted = nthreads;
}

ETP_API_DECL void ecb_cold
etp_set_max_parallel (unsigned int nthreads)
{
  if (wanted > nthreads)
    wanted = nthreads;

  while (started > wanted)
    etp_end_thread ();
}

Revision:	1.3
Committed:	Thu Jun 25 15:59:57 2015 UTC (8 years, 11 months ago) by root
Content type:	text/plain
Branch:	MAIN
Changes since 1.2:	+19 -1 lines
Log Message:	* empty log message *
#	Content
1	/*
2	* libetp implementation
3	*
4	* Copyright (c) 2007,2008,2009,2010,2011,2012,2013 Marc Alexander Lehmann <libetp@schmorp.de>
5	* 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	#ifndef ETP_API_DECL
41	# define ETP_API_DECL static
42	#endif
43
44	#ifndef ETP_PRI_MIN
45	# define ETP_PRI_MIN 0
46	# define ETP_PRI_MAX 0
47	#endif
48
49	#ifndef ETP_TYPE_QUIT
50	# define ETP_TYPE_QUIT 0
51	#endif
52
53	#ifndef ETP_TYPE_GROUP
54	# define ETP_TYPE_GROUP 1
55	#endif
56
57	#define ETP_NUM_PRI (ETP_PRI_MAX - ETP_PRI_MIN + 1)
58
59	#define ETP_TICKS ((1000000 + 1023) >> 10)
60
61	/* calculate time difference in ~1/ETP_TICKS of a second */
62	ecb_inline int
63	etp_tvdiff (struct timeval tv1, struct timeval tv2)
64	{
65	return (tv2->tv_sec - tv1->tv_sec ) * ETP_TICKS
66	+ ((tv2->tv_usec - tv1->tv_usec) >> 10);
67	}
68
69	static unsigned int started, idle, wanted = 4;
70
71	static void (*want_poll_cb) (void);
72	static void (*done_poll_cb) (void);
73
74	static unsigned int max_poll_time; /* reslock */
75	static unsigned int max_poll_reqs; /* reslock */
76
77	static unsigned int nreqs; /* reqlock */
78	static unsigned int nready; /* reqlock */
79	static unsigned int npending; /* reqlock */
80	static unsigned int max_idle = 4; /* maximum number of threads that can idle indefinitely */
81	static unsigned int idle_timeout = 10; /* number of seconds after which an idle threads exit */
82
83	static xmutex_t wrklock;
84	static xmutex_t reslock;
85	static xmutex_t reqlock;
86	static xcond_t reqwait;
87
88	struct etp_tmpbuf
89	{
90	void *ptr;
91	int len;
92	};
93
94	static void *
95	etp_tmpbuf_get (struct etp_tmpbuf *buf, int len)
96	{
97	if (buf->len < len)
98	{
99	free (buf->ptr);
100	buf->ptr = malloc (buf->len = len);
101	}
102
103	return buf->ptr;
104	}
105
106	typedef struct etp_worker
107	{
108	struct etp_tmpbuf tmpbuf;
109
110	/* locked by wrklock */
111	struct etp_worker prev, next;
112
113	xthread_t tid;
114
115	#ifdef ETP_WORKER_COMMON
116	ETP_WORKER_COMMON
117	#endif
118	} etp_worker;
119
120	static etp_worker wrk_first; /* NOT etp */
121
122	#define ETP_WORKER_LOCK(wrk) X_LOCK (wrklock)
123	#define ETP_WORKER_UNLOCK(wrk) X_UNLOCK (wrklock)
124
125	/* worker threads management */
126
127	static void
128	etp_worker_clear (etp_worker *wrk)
129	{
130	}
131
132	static void ecb_cold
133	etp_worker_free (etp_worker *wrk)
134	{
135	free (wrk->tmpbuf.ptr);
136
137	wrk->next->prev = wrk->prev;
138	wrk->prev->next = wrk->next;
139
140	free (wrk);
141	}
142
143	ETP_API_DECL unsigned int
144	etp_nreqs (void)
145	{
146	int retval;
147	if (WORDACCESS_UNSAFE) X_LOCK (reqlock);
148	retval = nreqs;
149	if (WORDACCESS_UNSAFE) X_UNLOCK (reqlock);
150	return retval;
151	}
152
153	ETP_API_DECL unsigned int
154	etp_nready (void)
155	{
156	unsigned int retval;
157
158	if (WORDACCESS_UNSAFE) X_LOCK (reqlock);
159	retval = nready;
160	if (WORDACCESS_UNSAFE) X_UNLOCK (reqlock);
161
162	return retval;
163	}
164
165	ETP_API_DECL unsigned int
166	etp_npending (void)
167	{
168	unsigned int retval;
169
170	if (WORDACCESS_UNSAFE) X_LOCK (reqlock);
171	retval = npending;
172	if (WORDACCESS_UNSAFE) X_UNLOCK (reqlock);
173
174	return retval;
175	}
176
177	ETP_API_DECL unsigned int
178	etp_nthreads (void)
179	{
180	unsigned int retval;
181
182	if (WORDACCESS_UNSAFE) X_LOCK (reqlock);
183	retval = started;
184	if (WORDACCESS_UNSAFE) X_UNLOCK (reqlock);
185
186	return retval;
187	}
188
189	/*
190	* a somewhat faster data structure might be nice, but
191	* with 8 priorities this actually needs <20 insns
192	* per shift, the most expensive operation.
193	*/
194	typedef struct {
195	ETP_REQ qs[ETP_NUM_PRI], qe[ETP_NUM_PRI]; /* qstart, qend */
196	int size;
197	} etp_reqq;
198
199	static etp_reqq req_queue;
200	static etp_reqq res_queue;
201
202	static void ecb_noinline ecb_cold
203	reqq_init (etp_reqq *q)
204	{
205	int pri;
206
207	for (pri = 0; pri < ETP_NUM_PRI; ++pri)
208	q->qs[pri] = q->qe[pri] = 0;
209
210	q->size = 0;
211	}
212
213	static int ecb_noinline
214	reqq_push (etp_reqq q, ETP_REQ req)
215	{
216	int pri = req->pri;
217	req->next = 0;
218
219	if (q->qe[pri])
220	{
221	q->qe[pri]->next = req;
222	q->qe[pri] = req;
223	}
224	else
225	q->qe[pri] = q->qs[pri] = req;
226
227	return q->size++;
228	}
229
230	static ETP_REQ * ecb_noinline
231	reqq_shift (etp_reqq *q)
232	{
233	int pri;
234
235	if (!q->size)
236	return 0;
237
238	--q->size;
239
240	for (pri = ETP_NUM_PRI; pri--; )
241	{
242	ETP_REQ *req = q->qs[pri];
243
244	if (req)
245	{
246	if (!(q->qs[pri] = (ETP_REQ *)req->next))
247	q->qe[pri] = 0;
248
249	return req;
250	}
251	}
252
253	abort ();
254	}
255
256	ETP_API_DECL int ecb_cold
257	etp_init (void (want_poll)(void), void (done_poll)(void))
258	{
259	X_MUTEX_CREATE (wrklock);
260	X_MUTEX_CREATE (reslock);
261	X_MUTEX_CREATE (reqlock);
262	X_COND_CREATE (reqwait);
263
264	reqq_init (&req_queue);
265	reqq_init (&res_queue);
266
267	wrk_first.next =
268	wrk_first.prev = &wrk_first;
269
270	started = 0;
271	idle = 0;
272	nreqs = 0;
273	nready = 0;
274	npending = 0;
275
276	want_poll_cb = want_poll;
277	done_poll_cb = done_poll;
278
279	return 0;
280	}
281
282	/* not yet in etp.c */
283	X_THREAD_PROC (etp_proc);
284
285	static void ecb_cold
286	etp_start_thread (void)
287	{
288	etp_worker *wrk = calloc (1, sizeof (etp_worker));
289
290	/TODO/
291	assert (("unable to allocate worker thread data", wrk));
292
293	X_LOCK (wrklock);
294
295	if (xthread_create (&wrk->tid, etp_proc, (void *)wrk))
296	{
297	wrk->prev = &wrk_first;
298	wrk->next = wrk_first.next;
299	wrk_first.next->prev = wrk;
300	wrk_first.next = wrk;
301	++started;
302	}
303	else
304	free (wrk);
305
306	X_UNLOCK (wrklock);
307	}
308
309	static void
310	etp_maybe_start_thread (void)
311	{
312	if (ecb_expect_true (etp_nthreads () >= wanted))
313	return;
314
315	/* todo: maybe use idle here, but might be less exact */
316	if (ecb_expect_true (0 <= (int)etp_nthreads () + (int)etp_npending () - (int)etp_nreqs ()))
317	return;
318
319	etp_start_thread ();
320	}
321
322	static void ecb_cold
323	etp_end_thread (void)
324	{
325	ETP_REQ req = calloc (1, sizeof (ETP_REQ)); / will be freed by worker */
326
327	req->type = ETP_TYPE_QUIT;
328	req->pri = ETP_PRI_MAX - ETP_PRI_MIN;
329
330	X_LOCK (reqlock);
331	reqq_push (&req_queue, req);
332	X_COND_SIGNAL (reqwait);
333	X_UNLOCK (reqlock);
334
335	X_LOCK (wrklock);
336	--started;
337	X_UNLOCK (wrklock);
338	}
339
340	ETP_API_DECL int
341	etp_poll (void)
342	{
343	unsigned int maxreqs;
344	unsigned int maxtime;
345	struct timeval tv_start, tv_now;
346
347	X_LOCK (reslock);
348	maxreqs = max_poll_reqs;
349	maxtime = max_poll_time;
350	X_UNLOCK (reslock);
351
352	if (maxtime)
353	gettimeofday (&tv_start, 0);
354
355	for (;;)
356	{
357	ETP_REQ *req;
358
359	etp_maybe_start_thread ();
360
361	X_LOCK (reslock);
362	req = reqq_shift (&res_queue);
363
364	if (req)
365	{
366	--npending;
367
368	if (!res_queue.size && done_poll_cb)
369	done_poll_cb ();
370	}
371
372	X_UNLOCK (reslock);
373
374	if (!req)
375	return 0;
376
377	X_LOCK (reqlock);
378	--nreqs;
379	X_UNLOCK (reqlock);
380
381	if (ecb_expect_false (req->type == ETP_TYPE_GROUP && req->size))
382	{
383	req->int1 = 1; /* mark request as delayed */
384	continue;
385	}
386	else
387	{
388	int res = ETP_FINISH (req);
389	if (ecb_expect_false (res))
390	return res;
391	}
392
393	if (ecb_expect_false (maxreqs && !--maxreqs))
394	break;
395
396	if (maxtime)
397	{
398	gettimeofday (&tv_now, 0);
399
400	if (etp_tvdiff (&tv_start, &tv_now) >= maxtime)
401	break;
402	}
403	}
404
405	errno = EAGAIN;
406	return -1;
407	}
408
409	ETP_API_DECL void
410	etp_grp_cancel (ETP_REQ *grp);
411
412	ETP_API_DECL void
413	etp_cancel (ETP_REQ *req)
414	{
415	req->cancelled = 1;
416
417	etp_grp_cancel (req);
418	}
419
420	ETP_API_DECL void
421	etp_grp_cancel (ETP_REQ *grp)
422	{
423	for (grp = grp->grp_first; grp; grp = grp->grp_next)
424	etp_cancel (grp);
425	}
426
427	ETP_API_DECL void
428	etp_submit (ETP_REQ *req)
429	{
430	req->pri -= ETP_PRI_MIN;
431
432	if (ecb_expect_false (req->pri < ETP_PRI_MIN - ETP_PRI_MIN)) req->pri = ETP_PRI_MIN - ETP_PRI_MIN;
433	if (ecb_expect_false (req->pri > ETP_PRI_MAX - ETP_PRI_MIN)) req->pri = ETP_PRI_MAX - ETP_PRI_MIN;
434
435	if (ecb_expect_false (req->type == ETP_TYPE_GROUP))
436	{
437	/* I hope this is worth it :/ */
438	X_LOCK (reqlock);
439	++nreqs;
440	X_UNLOCK (reqlock);
441
442	X_LOCK (reslock);
443
444	++npending;
445
446	if (!reqq_push (&res_queue, req) && want_poll_cb)
447	want_poll_cb ();
448
449	X_UNLOCK (reslock);
450	}
451	else
452	{
453	X_LOCK (reqlock);
454	++nreqs;
455	++nready;
456	reqq_push (&req_queue, req);
457	X_COND_SIGNAL (reqwait);
458	X_UNLOCK (reqlock);
459
460	etp_maybe_start_thread ();
461	}
462	}
463
464	ETP_API_DECL void ecb_cold
465	etp_set_max_poll_time (double nseconds)
466	{
467	if (WORDACCESS_UNSAFE) X_LOCK (reslock);
468	max_poll_time = nseconds * ETP_TICKS;
469	if (WORDACCESS_UNSAFE) X_UNLOCK (reslock);
470	}
471
472	ETP_API_DECL void ecb_cold
473	etp_set_max_poll_reqs (unsigned int maxreqs)
474	{
475	if (WORDACCESS_UNSAFE) X_LOCK (reslock);
476	max_poll_reqs = maxreqs;
477	if (WORDACCESS_UNSAFE) X_UNLOCK (reslock);
478	}
479
480	ETP_API_DECL void ecb_cold
481	etp_set_max_idle (unsigned int nthreads)
482	{
483	if (WORDACCESS_UNSAFE) X_LOCK (reqlock);
484	max_idle = nthreads;
485	if (WORDACCESS_UNSAFE) X_UNLOCK (reqlock);
486	}
487
488	ETP_API_DECL void ecb_cold
489	etp_set_idle_timeout (unsigned int seconds)
490	{
491	if (WORDACCESS_UNSAFE) X_LOCK (reqlock);
492	idle_timeout = seconds;
493	if (WORDACCESS_UNSAFE) X_UNLOCK (reqlock);
494	}
495
496	ETP_API_DECL void ecb_cold
497	etp_set_min_parallel (unsigned int nthreads)
498	{
499	if (wanted < nthreads)
500	wanted = nthreads;
501	}
502
503	ETP_API_DECL void ecb_cold
504	etp_set_max_parallel (unsigned int nthreads)
505	{
506	if (wanted > nthreads)
507	wanted = nthreads;
508
509	while (started > wanted)
510	etp_end_thread ();
511	}
512