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;

typedef struct etp_worker
{
  struct 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--; )
    {
      eio_req *req = q->qs[pri];

      if (req)
        {
          if (!(q->qs[pri] = (eio_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)
{
  eio_req *req = calloc (1, sizeof (eio_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:	1.1
Committed:	Sun Apr 14 09:43:19 2013 UTC (12 years, 8 months ago) by root
Content type:	text/plain
Branch:	MAIN
CVS Tags:	rel-4_2, rel-4_3, rel-4_31
Log Message:	move etp to etp.c, still not independent
#	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	typedef struct etp_worker
89	{
90	struct tmpbuf tmpbuf;
91
92	/* locked by wrklock */
93	struct etp_worker prev, next;
94
95	xthread_t tid;
96
97	#ifdef ETP_WORKER_COMMON
98	ETP_WORKER_COMMON
99	#endif
100	} etp_worker;
101
102	static etp_worker wrk_first; /* NOT etp */
103
104	#define ETP_WORKER_LOCK(wrk) X_LOCK (wrklock)
105	#define ETP_WORKER_UNLOCK(wrk) X_UNLOCK (wrklock)
106
107	/* worker threads management */
108
109	static void
110	etp_worker_clear (etp_worker *wrk)
111	{
112	}
113
114	static void ecb_cold
115	etp_worker_free (etp_worker *wrk)
116	{
117	free (wrk->tmpbuf.ptr);
118
119	wrk->next->prev = wrk->prev;
120	wrk->prev->next = wrk->next;
121
122	free (wrk);
123	}
124
125	ETP_API_DECL unsigned int
126	etp_nreqs (void)
127	{
128	int retval;
129	if (WORDACCESS_UNSAFE) X_LOCK (reqlock);
130	retval = nreqs;
131	if (WORDACCESS_UNSAFE) X_UNLOCK (reqlock);
132	return retval;
133	}
134
135	ETP_API_DECL unsigned int
136	etp_nready (void)
137	{
138	unsigned int retval;
139
140	if (WORDACCESS_UNSAFE) X_LOCK (reqlock);
141	retval = nready;
142	if (WORDACCESS_UNSAFE) X_UNLOCK (reqlock);
143
144	return retval;
145	}
146
147	ETP_API_DECL unsigned int
148	etp_npending (void)
149	{
150	unsigned int retval;
151
152	if (WORDACCESS_UNSAFE) X_LOCK (reqlock);
153	retval = npending;
154	if (WORDACCESS_UNSAFE) X_UNLOCK (reqlock);
155
156	return retval;
157	}
158
159	ETP_API_DECL unsigned int
160	etp_nthreads (void)
161	{
162	unsigned int retval;
163
164	if (WORDACCESS_UNSAFE) X_LOCK (reqlock);
165	retval = started;
166	if (WORDACCESS_UNSAFE) X_UNLOCK (reqlock);
167
168	return retval;
169	}
170
171	/*
172	* a somewhat faster data structure might be nice, but
173	* with 8 priorities this actually needs <20 insns
174	* per shift, the most expensive operation.
175	*/
176	typedef struct {
177	ETP_REQ qs[ETP_NUM_PRI], qe[ETP_NUM_PRI]; /* qstart, qend */
178	int size;
179	} etp_reqq;
180
181	static etp_reqq req_queue;
182	static etp_reqq res_queue;
183
184	static void ecb_noinline ecb_cold
185	reqq_init (etp_reqq *q)
186	{
187	int pri;
188
189	for (pri = 0; pri < ETP_NUM_PRI; ++pri)
190	q->qs[pri] = q->qe[pri] = 0;
191
192	q->size = 0;
193	}
194
195	static int ecb_noinline
196	reqq_push (etp_reqq q, ETP_REQ req)
197	{
198	int pri = req->pri;
199	req->next = 0;
200
201	if (q->qe[pri])
202	{
203	q->qe[pri]->next = req;
204	q->qe[pri] = req;
205	}
206	else
207	q->qe[pri] = q->qs[pri] = req;
208
209	return q->size++;
210	}
211
212	static ETP_REQ * ecb_noinline
213	reqq_shift (etp_reqq *q)
214	{
215	int pri;
216
217	if (!q->size)
218	return 0;
219
220	--q->size;
221
222	for (pri = ETP_NUM_PRI; pri--; )
223	{
224	eio_req *req = q->qs[pri];
225
226	if (req)
227	{
228	if (!(q->qs[pri] = (eio_req *)req->next))
229	q->qe[pri] = 0;
230
231	return req;
232	}
233	}
234
235	abort ();
236	}
237
238	ETP_API_DECL int ecb_cold
239	etp_init (void (want_poll)(void), void (done_poll)(void))
240	{
241	X_MUTEX_CREATE (wrklock);
242	X_MUTEX_CREATE (reslock);
243	X_MUTEX_CREATE (reqlock);
244	X_COND_CREATE (reqwait);
245
246	reqq_init (&req_queue);
247	reqq_init (&res_queue);
248
249	wrk_first.next =
250	wrk_first.prev = &wrk_first;
251
252	started = 0;
253	idle = 0;
254	nreqs = 0;
255	nready = 0;
256	npending = 0;
257
258	want_poll_cb = want_poll;
259	done_poll_cb = done_poll;
260
261	return 0;
262	}
263
264	/* not yet in etp.c */
265	X_THREAD_PROC (etp_proc);
266
267	static void ecb_cold
268	etp_start_thread (void)
269	{
270	etp_worker *wrk = calloc (1, sizeof (etp_worker));
271
272	/TODO/
273	assert (("unable to allocate worker thread data", wrk));
274
275	X_LOCK (wrklock);
276
277	if (xthread_create (&wrk->tid, etp_proc, (void *)wrk))
278	{
279	wrk->prev = &wrk_first;
280	wrk->next = wrk_first.next;
281	wrk_first.next->prev = wrk;
282	wrk_first.next = wrk;
283	++started;
284	}
285	else
286	free (wrk);
287
288	X_UNLOCK (wrklock);
289	}
290
291	static void
292	etp_maybe_start_thread (void)
293	{
294	if (ecb_expect_true (etp_nthreads () >= wanted))
295	return;
296
297	/* todo: maybe use idle here, but might be less exact */
298	if (ecb_expect_true (0 <= (int)etp_nthreads () + (int)etp_npending () - (int)etp_nreqs ()))
299	return;
300
301	etp_start_thread ();
302	}
303
304	static void ecb_cold
305	etp_end_thread (void)
306	{
307	eio_req req = calloc (1, sizeof (eio_req)); / will be freed by worker */
308
309	req->type = ETP_TYPE_QUIT;
310	req->pri = ETP_PRI_MAX - ETP_PRI_MIN;
311
312	X_LOCK (reqlock);
313	reqq_push (&req_queue, req);
314	X_COND_SIGNAL (reqwait);
315	X_UNLOCK (reqlock);
316
317	X_LOCK (wrklock);
318	--started;
319	X_UNLOCK (wrklock);
320	}
321
322	ETP_API_DECL int
323	etp_poll (void)
324	{
325	unsigned int maxreqs;
326	unsigned int maxtime;
327	struct timeval tv_start, tv_now;
328
329	X_LOCK (reslock);
330	maxreqs = max_poll_reqs;
331	maxtime = max_poll_time;
332	X_UNLOCK (reslock);
333
334	if (maxtime)
335	gettimeofday (&tv_start, 0);
336
337	for (;;)
338	{
339	ETP_REQ *req;
340
341	etp_maybe_start_thread ();
342
343	X_LOCK (reslock);
344	req = reqq_shift (&res_queue);
345
346	if (req)
347	{
348	--npending;
349
350	if (!res_queue.size && done_poll_cb)
351	done_poll_cb ();
352	}
353
354	X_UNLOCK (reslock);
355
356	if (!req)
357	return 0;
358
359	X_LOCK (reqlock);
360	--nreqs;
361	X_UNLOCK (reqlock);
362
363	if (ecb_expect_false (req->type == ETP_TYPE_GROUP && req->size))
364	{
365	req->int1 = 1; /* mark request as delayed */
366	continue;
367	}
368	else
369	{
370	int res = ETP_FINISH (req);
371	if (ecb_expect_false (res))
372	return res;
373	}
374
375	if (ecb_expect_false (maxreqs && !--maxreqs))
376	break;
377
378	if (maxtime)
379	{
380	gettimeofday (&tv_now, 0);
381
382	if (etp_tvdiff (&tv_start, &tv_now) >= maxtime)
383	break;
384	}
385	}
386
387	errno = EAGAIN;
388	return -1;
389	}
390
391	ETP_API_DECL void
392	etp_grp_cancel (ETP_REQ *grp);
393
394	ETP_API_DECL void
395	etp_cancel (ETP_REQ *req)
396	{
397	req->cancelled = 1;
398
399	etp_grp_cancel (req);
400	}
401
402	ETP_API_DECL void
403	etp_grp_cancel (ETP_REQ *grp)
404	{
405	for (grp = grp->grp_first; grp; grp = grp->grp_next)
406	etp_cancel (grp);
407	}
408
409	ETP_API_DECL void
410	etp_submit (ETP_REQ *req)
411	{
412	req->pri -= ETP_PRI_MIN;
413
414	if (ecb_expect_false (req->pri < ETP_PRI_MIN - ETP_PRI_MIN)) req->pri = ETP_PRI_MIN - ETP_PRI_MIN;
415	if (ecb_expect_false (req->pri > ETP_PRI_MAX - ETP_PRI_MIN)) req->pri = ETP_PRI_MAX - ETP_PRI_MIN;
416
417	if (ecb_expect_false (req->type == ETP_TYPE_GROUP))
418	{
419	/* I hope this is worth it :/ */
420	X_LOCK (reqlock);
421	++nreqs;
422	X_UNLOCK (reqlock);
423
424	X_LOCK (reslock);
425
426	++npending;
427
428	if (!reqq_push (&res_queue, req) && want_poll_cb)
429	want_poll_cb ();
430
431	X_UNLOCK (reslock);
432	}
433	else
434	{
435	X_LOCK (reqlock);
436	++nreqs;
437	++nready;
438	reqq_push (&req_queue, req);
439	X_COND_SIGNAL (reqwait);
440	X_UNLOCK (reqlock);
441
442	etp_maybe_start_thread ();
443	}
444	}
445
446	ETP_API_DECL void ecb_cold
447	etp_set_max_poll_time (double nseconds)
448	{
449	if (WORDACCESS_UNSAFE) X_LOCK (reslock);
450	max_poll_time = nseconds * ETP_TICKS;
451	if (WORDACCESS_UNSAFE) X_UNLOCK (reslock);
452	}
453
454	ETP_API_DECL void ecb_cold
455	etp_set_max_poll_reqs (unsigned int maxreqs)
456	{
457	if (WORDACCESS_UNSAFE) X_LOCK (reslock);
458	max_poll_reqs = maxreqs;
459	if (WORDACCESS_UNSAFE) X_UNLOCK (reslock);
460	}
461
462	ETP_API_DECL void ecb_cold
463	etp_set_max_idle (unsigned int nthreads)
464	{
465	if (WORDACCESS_UNSAFE) X_LOCK (reqlock);
466	max_idle = nthreads;
467	if (WORDACCESS_UNSAFE) X_UNLOCK (reqlock);
468	}
469
470	ETP_API_DECL void ecb_cold
471	etp_set_idle_timeout (unsigned int seconds)
472	{
473	if (WORDACCESS_UNSAFE) X_LOCK (reqlock);
474	idle_timeout = seconds;
475	if (WORDACCESS_UNSAFE) X_UNLOCK (reqlock);
476	}
477
478	ETP_API_DECL void ecb_cold
479	etp_set_min_parallel (unsigned int nthreads)
480	{
481	if (wanted < nthreads)
482	wanted = nthreads;
483	}
484
485	ETP_API_DECL void ecb_cold
486	etp_set_max_parallel (unsigned int nthreads)
487	{
488	if (wanted > nthreads)
489	wanted = nthreads;
490
491	while (started > wanted)
492	etp_end_thread ();
493	}
494