beblocksched.c 16.6 KB
Newer Older
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
/*
 * Author:      Matthias Braun, Christoph Mallon
 * Date:		27.09.2006
 * Copyright:   (c) Universitaet Karlsruhe
 * License:     This file is protected by GPL -  GNU GENERAL PUBLIC LICENSE.
 *
 */
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "beblocksched.h"

#include <stdlib.h>

#include "array.h"
#include "pdeq.h"

#include "iredges.h"
#include "irgwalk.h"
#include "irgraph_t.h"
#include "irloop.h"
#include "irprintf.h"
#include "irdump_t.h"
#include "beirgmod.h"

#ifdef WITH_LIBCORE
#include <libcore/lc_opts.h>
#include <libcore/lc_opts_enum.h>
#include <libcore/lc_timing.h>
#endif

#ifdef WITH_ILP
#include <lpp/lpp.h>
#include <lpp/lpp_net.h>
#endif

typedef enum _blocksched_algos_t {
	BLOCKSCHED_NAIV, BLOCKSCHED_EXTBB, BLOCKSCHED_GREEDY, BLOCKSCHED_ILP
} blocksched_algos_t;

static int algo = BLOCKSCHED_GREEDY;

static const lc_opt_enum_int_items_t blockschedalgo_items[] = {
	{ "naiv",	BLOCKSCHED_NAIV },
	{ "extbb",	BLOCKSCHED_EXTBB },
	{ "greedy", BLOCKSCHED_GREEDY },
#ifdef WITH_ILP
	{ "ilp",    BLOCKSCHED_ILP },
#endif
	{ NULL,     0 }
};

static lc_opt_enum_int_var_t algo_var = {
	&algo, blockschedalgo_items
};

static const lc_opt_table_entry_t be_blocksched_options[] = {
	LC_OPT_ENT_ENUM_INT ("algo", "the block scheduling algorithm", &algo_var),
	{ NULL }
};

/*
 *   ____                   _
 *  / ___|_ __ ___  ___  __| |_   _
 * | |  _| '__/ _ \/ _ \/ _` | | | |
 * | |_| | | |  __/  __/ (_| | |_| |
 *  \____|_|  \___|\___|\__,_|\__, |
 *                            |___/
 */

typedef struct _blocksched_entry_t {
	ir_node *block;
	struct _blocksched_entry_t *next;
	struct _blocksched_entry_t *prev;
} blocksched_entry_t;

typedef struct _edge_t {
	ir_node *block;
	int pos;
	double execfreq;
	int highest_execfreq;		/**< flag that indicates wether this edge is the edge with the highest
							   	     execfreq pointing away from this block */
} edge_t;

typedef struct _blocksched_env_t {
	ir_graph *irg;
	struct obstack *obst;
	ir_exec_freq *execfreqs;
	edge_t *edges;
	pdeq *worklist;
	int blockcount;
} blocksched_env_t;

static void collect_egde_frequency(ir_node *block, void *data)
{
	blocksched_env_t *env = data;
	ir_graph *irg = env->irg;
	ir_node *startblock = get_irg_start_block(irg);
	int arity;
	edge_t edge;
	blocksched_entry_t *entry;

	entry = obstack_alloc(env->obst, sizeof(entry[0]));
	entry->block = block;
	entry->next = NULL;
	entry->prev = NULL;
	set_irn_link(block, entry);

	if(block == startblock)
		return;

	arity = get_irn_arity(block);
	if(arity == 1) {
		edge.block = block;
		edge.pos = 0;
		edge.execfreq = get_block_execfreq(env->execfreqs, block);
		edge.highest_execfreq = 1;
		ARR_APP1(edge_t, env->edges, edge);
	} else {
		int i;
		double highest_execfreq = -1;
		int highest_edge_num;

		edge.block = block;
		for(i = 0; i < arity; ++i) {
			double execfreq;

			ir_node *pred_block = get_Block_cfgpred_block(block, i);
			execfreq = get_block_execfreq(env->execfreqs, pred_block);

			edge.pos = i;
			edge.execfreq = execfreq;
			edge.highest_execfreq = 0;
			ARR_APP1(edge_t, env->edges, edge);
			if(execfreq > highest_execfreq) {
				highest_execfreq = execfreq;
				highest_edge_num = ARR_LEN(env->edges) - 1;
			}
		}

		env->edges[highest_edge_num].highest_execfreq = 1;
	}
}

static int cmp_edges(const void *d1, const void *d2)
{
	const edge_t *e1 = d1;
	const edge_t *e2 = d2;
Michael Beck's avatar
Michael Beck committed
150
151
152
	if (e2->execfreq > e1->execfreq) return 1;
	if (e2->execfreq < e1->execfreq) return -1;
	return 0;
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
}

static void coalesce_blocks(blocksched_env_t *env)
{
	int i;
	int edge_count = ARR_LEN(env->edges);

	// run1: only look at jumps
	for(i = 0; i < edge_count; ++i) {
		const edge_t *edge = & env->edges[i];
		ir_node *block = edge->block;
		ir_node *pred_block;
		blocksched_entry_t *entry, *pred_entry;

		// the block might have been removed already...
		if(is_Bad(get_Block_cfgpred(block, 0)))
			continue;

		if(!edge->highest_execfreq)
			continue;

		pred_block = get_Block_cfgpred_block(block, edge->pos);
		entry = get_irn_link(block);
		pred_entry = get_irn_link(pred_block);

		if(pred_entry->next != NULL || entry->prev != NULL)
			continue;
		// only coalesce jumps
		if(get_block_succ_next(pred_block, get_block_succ_first(pred_block)) != NULL)
			continue;

		// schedule the 2 blocks behind each other
		ir_fprintf(stderr, "Coalesce (Jump) %+F -> %+F (%.3g)\n",
		           pred_entry->block, entry->block, edge->execfreq);
		pred_entry->next = entry;
		entry->prev = pred_entry;
	}

	// run2: remaining edges
	for(i = 0; i < edge_count; ++i) {
		const edge_t *edge = & env->edges[i];
		ir_node *block = edge->block;
		ir_node *pred_block;
		blocksched_entry_t *entry, *pred_entry;

		// the block might have been removed already...
		if(is_Bad(get_Block_cfgpred(block, 0)))
			continue;

		pred_block = get_Block_cfgpred_block(block, edge->pos);
		entry = get_irn_link(block);
		pred_entry = get_irn_link(pred_block);

		if(pred_entry->next != NULL || entry->prev != NULL)
			continue;

		// schedule the 2 blocks behind each other
		ir_fprintf(stderr, "Coalesce (CondJump) %+F -> %+F (%.3g)\n",
		           pred_entry->block, entry->block, edge->execfreq);
		pred_entry->next = entry;
		entry->prev = pred_entry;
	}
}

static void pick_block_successor(blocksched_entry_t *entry, blocksched_env_t *env)
{
	ir_node *block = entry->block;
	blocksched_entry_t *succ_entry;
	const ir_edge_t *edge;
	double best_succ_execfreq;
	ir_node *succ = NULL;

	if(irn_visited(block))
		return;
	env->blockcount++;
	mark_irn_visited(block);

	ir_fprintf(stderr, "Pick succ of %+F\n", block);

	// put all successors into the worklist
	foreach_block_succ(block, edge) {
		ir_node *succ_block = get_edge_src_irn(edge);

		if(irn_visited(succ_block))
			continue;

		// we only need to put the first of a series of already connected
		// blocks into the worklist
		succ_entry = get_irn_link(succ_block);
		while(succ_entry->prev != NULL) {
			// break cycles...
			if(succ_entry->prev->block == succ_block) {
				succ_entry->prev->next = NULL;
				succ_entry->prev = NULL;
				break;
			}
			succ_entry = succ_entry->prev;
		};

		if(irn_visited(succ_entry->block))
			continue;

		ir_fprintf(stderr, "Put %+F into worklist\n", succ_entry->block);
		pdeq_putr(env->worklist, succ_entry->block);
	}

	if(entry->next != NULL) {
		pick_block_successor(entry->next, env);
		return;
	}

	fprintf(stderr, "deciding...\n");
	best_succ_execfreq = -1;
	/* no successor yet: pick the successor block with the highest execution
	 * frequency which has no predecessor yet
	 */
	foreach_block_succ(block, edge) {
		ir_node *succ_block = get_edge_src_irn(edge);
Michael Beck's avatar
Michael Beck committed
271
		double execfreq;
272
273
274
275
276
277
278
279

		if(irn_visited(succ_block))
			continue;

		succ_entry = get_irn_link(succ_block);
		if(succ_entry->prev != NULL)
			continue;

Michael Beck's avatar
Michael Beck committed
280
		execfreq = get_block_execfreq(env->execfreqs, succ_block);
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
		if(execfreq > best_succ_execfreq) {
			best_succ_execfreq = execfreq;
			succ = succ_block;
		}
	}

	if(succ == NULL) {
		fprintf(stderr, "pick from worklist\n");

		do {
			if(pdeq_empty(env->worklist)) {
				fprintf(stderr, "worklist empty\n");
				return;
			}
			succ = pdeq_getl(env->worklist);
		} while(irn_visited(succ));
	}

	succ_entry = get_irn_link(succ);
	entry->next = succ_entry;
	succ_entry->prev = entry;

	pick_block_successor(succ_entry, env);
}

static blocksched_entry_t *finish_block_schedule(blocksched_env_t *env)
{
	ir_graph *irg = env->irg;
	ir_node *startblock = get_irg_start_block(irg);
	blocksched_entry_t *entry = get_irn_link(startblock);

	inc_irg_visited(irg);

	env->worklist = new_pdeq();
	pick_block_successor(entry, env);
	assert(pdeq_empty(env->worklist));
	del_pdeq(env->worklist);

	return entry;
}

static ir_node **create_blocksched_array(blocksched_entry_t *first, int count,
                                         struct obstack* obst) {
	int i = 0;
	ir_node **block_list;
	blocksched_entry_t *entry;

	block_list = NEW_ARR_D(ir_node *, obst, count);
	fprintf(stderr, "Blockschedule:\n");
	for(entry = first; entry != NULL; entry = entry->next) {
		assert(i < count);
		block_list[i++] = entry->block;
		ir_fprintf(stderr, "\t%+F\n", entry->block);
	}
	assert(i == count);

	return block_list;
}

static ir_node **create_block_schedule_greedy(ir_graph *irg, ir_exec_freq *execfreqs)
{
	blocksched_env_t env;
	struct obstack obst;
	blocksched_entry_t *start_entry;
	ir_node **block_list;

	obstack_init(&obst);

	env.irg = irg;
	env.obst = &obst;
	env.execfreqs = execfreqs;
	env.edges = NEW_ARR_F(edge_t, 0);
	env.worklist = NULL;
	env.blockcount = 0;

	// collect edge execution frequencies
	irg_block_walk_graph(irg, collect_egde_frequency, NULL, &env);

	// sort interblock edges by execution frequency
	qsort(env.edges, ARR_LEN(env.edges), sizeof(env.edges[0]), cmp_edges);

	be_remove_empty_blocks(irg);

	if(algo != BLOCKSCHED_NAIV)
		coalesce_blocks(&env);

	start_entry = finish_block_schedule(&env);

	block_list = create_blocksched_array(start_entry, env.blockcount, get_irg_obstack(irg));

	DEL_ARR_F(env.edges);
	obstack_free(&obst, NULL);

	return block_list;
}

/*
 *  ___ _     ____
 * |_ _| |   |  _ \
 *  | || |   | |_) |
 *  | || |___|  __/
 * |___|_____|_|
 *
 */

#ifdef WITH_ILP
typedef struct _ilp_edge_t {
	ir_node *block;
	int pos;
	int ilpvar;
} ilp_edge_t;

typedef struct _blocksched_ilp_env_t {
	blocksched_env_t env;
	ilp_edge_t *ilpedges;
	lpp_t *lpp;
} blocksched_ilp_env_t;

typedef struct _blocksched_ilp_entry_t {
	ir_node *block;
	struct _blocksched_entry_t *next;
	struct _blocksched_entry_t *prev;

	int out_cst;
} blocksched_ilp_entry_t;

static int add_ilp_edge(ir_node *block, int pos, double execfreq, blocksched_ilp_env_t *env)
{
	char name[64];
	ilp_edge_t edge;
	int edgeidx = ARR_LEN(env->ilpedges);

	snprintf(name, sizeof(name), "edge%d", edgeidx);

	edge.block = block;
	edge.pos = pos;
	edge.ilpvar = lpp_add_var_default(env->lpp, name, lpp_binary, execfreq, 1.0);

	ARR_APP1(ilp_edge_t, env->ilpedges, edge);
	return edgeidx;
}

static void collect_egde_frequency_ilp(ir_node *block, void *data)
{
	blocksched_ilp_env_t *env = data;
	ir_graph *irg = env->env.irg;
	ir_node *startblock = get_irg_start_block(irg);
	int arity;
	blocksched_ilp_entry_t *entry;
	lpp_cst_t cst;
	char name[64];
	int out_count;

	snprintf(name, sizeof(name), "block_out_constr_%ld", get_irn_node_nr(block));
	out_count = get_irn_n_edges_kind(block, EDGE_KIND_BLOCK);

	entry = obstack_alloc(env->env.obst, sizeof(entry[0]));
	entry->block = block;
	entry->next = NULL;
	entry->prev = NULL;
	entry->out_cst = lpp_add_cst_uniq(env->lpp, name, lpp_greater, out_count - 1);
	set_irn_link(block, entry);

	if(block == startblock)
		return;

	arity = get_irn_arity(block);
	if(arity == 1) {
		double execfreq = get_block_execfreq(env->env.execfreqs, block);
		add_ilp_edge(block, 0, execfreq, env);
	} else {
		int i;
		int *edgenums = alloca(sizeof(edgenums[0]) * arity);

		snprintf(name, sizeof(name), "block_in_constr_%ld", get_irn_node_nr(block));
		cst = lpp_add_cst_uniq(env->lpp, name, lpp_greater, arity - 1);

		for(i = 0; i < arity; ++i) {
			double execfreq;
			int edgenum;
			ilp_edge_t *edge;

			ir_node *pred_block = get_Block_cfgpred_block(block, i);
			execfreq = get_block_execfreq(env->env.execfreqs, pred_block);

			edgenum = add_ilp_edge(block, i, execfreq, env);
			edge = & env->ilpedges[edgenum];
			lpp_set_factor_fast(env->lpp, cst, edge->ilpvar, 1.0);
		}
	}
}


static void coalesce_blocks_ilp(blocksched_ilp_env_t *env)
{
	int i;
	int edge_count = ARR_LEN(env->ilpedges);
	FILE *f;
	char fname[256];

	/* complete out constraints */
	for(i = 0; i < edge_count; ++i) {
		const ilp_edge_t *edge = & env->ilpedges[i];
		ir_node *block = edge->block;
		ir_node *pred;
		blocksched_ilp_entry_t *entry;

		// the block might have been removed already...
		if(is_Bad(get_Block_cfgpred(block, 0)))
			continue;

		pred = get_Block_cfgpred_block(block, edge->pos);
		entry = get_irn_link(pred);

		ir_printf("Adding out cst to %+F from %+F,%d\n",
				  pred, block, edge->pos);
		lpp_set_factor_fast(env->lpp, entry->out_cst, edge->ilpvar, 1.0);
	}

	lpp_dump(env->lpp, "lpp.out");
	snprintf(fname, sizeof(fname), "lpp_%s.plain", get_irg_dump_name(env->env.irg));
	f = fopen(fname, "w");
	lpp_dump_plain(env->lpp, f);
	fclose(f);
	//lpp_solve_net(env->lpp, main_env->options->ilp_server, main_env->options->ilp_solver);
	lpp_solve_net(env->lpp, "i44pc52", "cplex");
	assert(lpp_is_sol_valid(env->lpp));

	/* Apply results to edges */
	for(i = 0; i < edge_count; ++i) {
		const ilp_edge_t *edge = & env->ilpedges[i];
		ir_node *block = edge->block;
		ir_node *pred;
		int is_jump;
		blocksched_entry_t *entry;
		blocksched_entry_t *pred_entry;

		// the block might have been removed already...
		if(is_Bad(get_Block_cfgpred(block, 0)))
			continue;

		is_jump = lpp_get_var_sol(env->lpp, edge->ilpvar);
		if(is_jump)
			continue;

		pred = get_Block_cfgpred_block(block, edge->pos);
		entry = get_irn_link(block);
		pred_entry = get_irn_link(pred);

		assert(entry->prev == NULL && pred_entry->next == NULL);
		entry->prev = pred_entry;
		pred_entry->next = entry;
	}
}

static ir_node **create_block_schedule_ilp(ir_graph *irg, ir_exec_freq *execfreqs)
{
	blocksched_ilp_env_t env;
	struct obstack obst;
	blocksched_entry_t *start_entry;
	ir_node **block_list;

	obstack_init(&obst);

	env.env.irg = irg;
	env.env.obst = &obst;
	env.env.execfreqs = execfreqs;
	env.env.worklist = NULL;
	env.env.blockcount = 0;
	env.ilpedges = NEW_ARR_F(ilp_edge_t, 0);

	env.lpp = new_lpp("blockschedule", lpp_minimize);
	lpp_set_time_limit(env.lpp, 20);
	lpp_set_log(env.lpp, stdout);

	irg_block_walk_graph(irg, collect_egde_frequency_ilp, NULL, &env);

	be_remove_empty_blocks(irg);

	coalesce_blocks_ilp(&env);

	start_entry = finish_block_schedule(&env.env);

	block_list = create_blocksched_array(start_entry, env.env.blockcount, get_irg_obstack(irg));

	DEL_ARR_F(env.ilpedges);
	free_lpp(env.lpp);
	obstack_free(&obst, NULL);

	return block_list;
}
#endif

/*
 *  _____      _   ____  ____
 * | ____|_  _| |_| __ )| __ )
 * |  _| \ \/ / __|  _ \|  _ \
 * | |___ >  <| |_| |_) | |_) |
 * |_____/_/\_\\__|____/|____/
 *
 */

/** A simple forward single linked list. */
typedef struct {
	ir_node *start;   /**< start of the list */
	ir_node *end;     /**< last block in the list */
	unsigned n_blks;  /**< number of blocks in the list */
} anchor;

static void add_block(anchor *list, ir_node *block) {
	if(list->start == NULL) {
		list->start = block;
		list->end = block;
	} else {
		set_irn_link(list->end, block);
		list->end = block;
	}

	list->n_blks++;
}

static void create_block_list(ir_node *leader_block, anchor *list) {
	int i;
	ir_node *block = NULL;
	const ir_edge_t *edge;

	ir_extblk *extbb = get_Block_extbb(leader_block);
	if(extbb_visited(extbb))
		return;
	mark_extbb_visited(extbb);

	for(i = 0; i < get_extbb_n_blocks(extbb); ++i) {
		block = get_extbb_block(extbb, i);
		add_block(list, block);
	}

	assert(block != NULL);

	// pick successor extbbs
	foreach_block_succ(block, edge) {
		ir_node *succ = get_edge_src_irn(edge);

		create_block_list(succ, list);
	}

	for(i = 0; i < get_extbb_n_blocks(extbb) - 1; ++i) {
		block = get_extbb_block(extbb, i);
		foreach_block_succ(block, edge) {
			ir_node *succ = get_edge_src_irn(edge);

			create_block_list(succ, list);
		}
	}
}

void compute_extbb_execfreqs(ir_graph *irg, ir_exec_freq *execfreqs);

/*
 * Calculates a block schedule. The schedule is stored as a linked
 * list starting at the start_block of the irg.
 */
static ir_node **create_extbb_block_schedule(ir_graph *irg, ir_exec_freq *execfreqs)
{
	anchor list;
	ir_node **blk_list, *b, *n;
	unsigned i;

	/* schedule extended basic blocks */
	compute_extbb_execfreqs(irg, execfreqs);
	//compute_extbb(irg);

	list.start  = NULL;
	list.end    = NULL;
	list.n_blks = 0;
	inc_irg_block_visited(irg);
	create_block_list(get_irg_start_block(irg), &list);

	/** create an array, so we can go forward and backward */
	blk_list = NEW_ARR_D(ir_node *, irg->obst,list.n_blks);

	for (i = 0, b = list.start; b; b = n, ++i) {
		n = get_irn_link(b);
		blk_list[i] = b;
	}

	return blk_list;
}

/*
 *  __  __       _
 * |  \/  | __ _(_)_ __
 * | |\/| |/ _` | | '_ \
 * | |  | | (_| | | | | |
 * |_|  |_|\__,_|_|_| |_|
 *
 */

#ifdef WITH_LIBCORE
void be_block_schedule_register_options(lc_opt_entry_t *grp)
{
	static int run_once = 0;
	lc_opt_entry_t *blocksched_grp;

	if(run_once)
		return;
	run_once = 1;
	blocksched_grp = lc_opt_get_grp(grp, "blocksched");

	lc_opt_add_table(blocksched_grp, be_blocksched_options);
}
#endif

ir_node **be_create_block_schedule(ir_graph *irg, ir_exec_freq *execfreqs)
{
	switch(algo) {
	case BLOCKSCHED_GREEDY:
	case BLOCKSCHED_NAIV:
		return create_block_schedule_greedy(irg, execfreqs);
	case BLOCKSCHED_EXTBB:
		return create_extbb_block_schedule(irg, execfreqs);
#ifdef WITH_ILP
	case BLOCKSCHED_ILP:
		return create_block_schedule_ilp(irg, execfreqs);
#endif
	}

	assert(0 && "unknown blocksched algo");
	return NULL;
}