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 (11 years, 4 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
#	User	Rev	Content
1	root	1.1	/*
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