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[/] [openrisc/] [trunk/] [gnu-stable/] [gdb-7.2/] [sim/] [common/] [cgen-scache.c] - Blame information for rev 835

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1 330 jeremybenn
/* Simulator cache routines for CGEN simulators (and maybe others).
2
   Copyright (C) 1996, 1997, 1998, 2007, 2008, 2009, 2010
3
   Free Software Foundation, Inc.
4
   Contributed by Cygnus Support.
5
 
6
This file is part of GDB, the GNU debugger.
7
 
8
This program is free software; you can redistribute it and/or modify
9
it under the terms of the GNU General Public License as published by
10
the Free Software Foundation; either version 3 of the License, or
11
(at your option) any later version.
12
 
13
This program is distributed in the hope that it will be useful,
14
but WITHOUT ANY WARRANTY; without even the implied warranty of
15
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16
GNU General Public License for more details.
17
 
18
You should have received a copy of the GNU General Public License
19
along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
20
 
21
#define SCACHE_DEFINE_INLINE
22
 
23
#include "sim-main.h"
24
#ifdef HAVE_STDLIB_H
25
#include <stdlib.h>
26
#endif
27
#include "libiberty.h"
28
#include "sim-options.h"
29
#include "sim-io.h"
30
 
31
#define MAX(a,b) ((a) > (b) ? (a) : (b))
32
 
33
/* Unused address.  */
34
#define UNUSED_ADDR 0xffffffff
35
 
36
/* Scache configuration parameters.
37
   ??? Experiments to determine reasonable values is wip.
38
   These are just guesses.  */
39
 
40
/* Default number of scache elements.
41
   The size of an element is typically 32-64 bytes, so the size of the
42
   default scache will be between 512K and 1M bytes.  */
43
#ifdef CONFIG_SIM_CACHE_SIZE
44
#define SCACHE_DEFAULT_CACHE_SIZE CONFIG_SIM_CACHE_SIZE
45
#else
46
#define SCACHE_DEFAULT_CACHE_SIZE 16384
47
#endif
48
 
49
/* Minimum cache size.
50
   The m32r port assumes a cache size of at least 2 so it can decode both 16
51
   bit insns.  When compiling we need an extra for the chain entry.  And this
52
   must be a multiple of 2.  Hence 4 is the minimum (though, for those with
53
   featuritis or itchy pedantic bits, we could make this conditional on
54
   WITH_SCACHE_PBB).  */
55
#define MIN_SCACHE_SIZE 4
56
 
57
/* Ratio of size of text section to size of scache.
58
   When compiling, we don't want to flush the scache more than we have to
59
   but we also don't want it to be exorbitantly(sp?) large.  So we pick a high
60
   default value, then reduce it by the size of the program being simulated,
61
   but we don't override any value specified on the command line.
62
   If not specified on the command line, the size to use is computed as
63
   max (MIN_SCACHE_SIZE,
64
        min (DEFAULT_SCACHE_SIZE,
65
             text_size / (base_insn_size * INSN_SCACHE_RATIO))).  */
66
/* ??? Interesting idea but not currently used.  */
67
#define INSN_SCACHE_RATIO 4
68
 
69
/* Default maximum insn chain length.
70
   The only reason for a maximum is so we can place a maximum size on the
71
   profiling table.  Chain lengths are determined by cti's.
72
   32 is a more reasonable number, but when profiling, the before/after
73
   handlers take up that much more space.  The scache is filled from front to
74
   back so all this determines is when the scache needs to be flushed.  */
75
#define MAX_CHAIN_LENGTH 64
76
 
77
/* Default maximum hash list length.  */
78
#define MAX_HASH_CHAIN_LENGTH 4
79
 
80
/* Minimum hash table size.  */
81
#define MIN_HASH_CHAINS 32
82
 
83
/* Ratio of number of scache elements to number of hash lists.
84
   Since the user can only specify the size of the scache, we compute the
85
   size of the hash table as
86
   max (MIN_HASH_CHAINS, scache_size / SCACHE_HASH_RATIO).  */
87
#define SCACHE_HASH_RATIO 8
88
 
89
/* Hash a PC value.
90
   FIXME: May wish to make the hashing architecture specific.
91
   FIXME: revisit */
92
#define HASH_PC(pc) (((pc) >> 2) + ((pc) >> 5))
93
 
94
static MODULE_INIT_FN scache_init;
95
static MODULE_UNINSTALL_FN scache_uninstall;
96
 
97
static DECLARE_OPTION_HANDLER (scache_option_handler);
98
 
99
#define OPTION_PROFILE_SCACHE   (OPTION_START + 0)
100
 
101
static const OPTION scache_options[] = {
102
  { {"scache-size", optional_argument, NULL, 'c'},
103
      'c', "[SIZE]", "Specify size of simulator execution cache",
104
      scache_option_handler },
105
#if WITH_SCACHE_PBB
106
  /* ??? It might be nice to allow the user to specify the size of the hash
107
     table, the maximum hash list length, and the maximum chain length, but
108
     for now that might be more akin to featuritis.  */
109
#endif
110
  { {"profile-scache", optional_argument, NULL, OPTION_PROFILE_SCACHE},
111
      '\0', "on|off", "Perform simulator execution cache profiling",
112
      scache_option_handler },
113
  { {NULL, no_argument, NULL, 0}, '\0', NULL, NULL, NULL }
114
};
115
 
116
static SIM_RC
117
scache_option_handler (SIM_DESC sd, sim_cpu *cpu, int opt,
118
                       char *arg, int is_command)
119
{
120
  switch (opt)
121
    {
122
    case 'c' :
123
      if (WITH_SCACHE)
124
        {
125
          if (arg != NULL)
126
            {
127
              int n = strtol (arg, NULL, 0);
128
              if (n < MIN_SCACHE_SIZE)
129
                {
130
                  sim_io_eprintf (sd, "invalid scache size `%d', must be at least 4", n);
131
                  return SIM_RC_FAIL;
132
                }
133
              /* Ensure it's a multiple of 2.  */
134
              if ((n & (n - 1)) != 0)
135
                {
136
                  sim_io_eprintf (sd, "scache size `%d' not a multiple of 2\n", n);
137
                  {
138
                    /* round up to nearest multiple of 2 */
139
                    int i;
140
                    for (i = 1; i < n; i <<= 1)
141
                      continue;
142
                    n = i;
143
                  }
144
                  sim_io_eprintf (sd, "rounding scache size up to %d\n", n);
145
                }
146
              if (cpu == NULL)
147
                STATE_SCACHE_SIZE (sd) = n;
148
              else
149
                CPU_SCACHE_SIZE (cpu) = n;
150
            }
151
          else
152
            {
153
              if (cpu == NULL)
154
                STATE_SCACHE_SIZE (sd) = SCACHE_DEFAULT_CACHE_SIZE;
155
              else
156
                CPU_SCACHE_SIZE (cpu) = SCACHE_DEFAULT_CACHE_SIZE;
157
            }
158
        }
159
      else
160
        sim_io_eprintf (sd, "Simulator execution cache not enabled, `--scache-size' ignored\n");
161
      break;
162
 
163
    case OPTION_PROFILE_SCACHE :
164
      if (WITH_SCACHE && WITH_PROFILE_SCACHE_P)
165
        {
166
          /* FIXME: handle cpu != NULL.  */
167
          return sim_profile_set_option (sd, "-scache", PROFILE_SCACHE_IDX,
168
                                         arg);
169
        }
170
      else
171
        sim_io_eprintf (sd, "Simulator cache profiling not compiled in, `--profile-scache' ignored\n");
172
      break;
173
    }
174
 
175
  return SIM_RC_OK;
176
}
177
 
178
SIM_RC
179
scache_install (SIM_DESC sd)
180
{
181
  sim_add_option_table (sd, NULL, scache_options);
182
  sim_module_add_init_fn (sd, scache_init);
183
  sim_module_add_uninstall_fn (sd, scache_uninstall);
184
 
185
  /* This is the default, it may be overridden on the command line.  */
186
  STATE_SCACHE_SIZE (sd) = WITH_SCACHE;
187
 
188
  return SIM_RC_OK;
189
}
190
 
191
static SIM_RC
192
scache_init (SIM_DESC sd)
193
{
194
  int c;
195
 
196
  for (c = 0; c < MAX_NR_PROCESSORS; ++c)
197
    {
198
      SIM_CPU *cpu = STATE_CPU (sd, c);
199
      int elm_size = IMP_PROPS_SCACHE_ELM_SIZE (MACH_IMP_PROPS (CPU_MACH (cpu)));
200
 
201
      /* elm_size is 0 if the cpu doesn't not have scache support */
202
      if (elm_size == 0)
203
        {
204
          CPU_SCACHE_SIZE (cpu) = 0;
205
          CPU_SCACHE_CACHE (cpu) = NULL;
206
        }
207
      else
208
        {
209
          if (CPU_SCACHE_SIZE (cpu) == 0)
210
            CPU_SCACHE_SIZE (cpu) = STATE_SCACHE_SIZE (sd);
211
          CPU_SCACHE_CACHE (cpu) =
212
            (SCACHE *) xmalloc (CPU_SCACHE_SIZE (cpu) * elm_size);
213
#if WITH_SCACHE_PBB
214
          CPU_SCACHE_MAX_CHAIN_LENGTH (cpu) = MAX_CHAIN_LENGTH;
215
          CPU_SCACHE_NUM_HASH_CHAIN_ENTRIES (cpu) = MAX_HASH_CHAIN_LENGTH;
216
          CPU_SCACHE_NUM_HASH_CHAINS (cpu) = MAX (MIN_HASH_CHAINS,
217
                                                  CPU_SCACHE_SIZE (cpu)
218
                                                  / SCACHE_HASH_RATIO);
219
          CPU_SCACHE_HASH_TABLE (cpu) =
220
            (SCACHE_MAP *) xmalloc (CPU_SCACHE_NUM_HASH_CHAINS (cpu)
221
                                    * CPU_SCACHE_NUM_HASH_CHAIN_ENTRIES (cpu)
222
                                    * sizeof (SCACHE_MAP));
223
          CPU_SCACHE_PBB_BEGIN (cpu) = (SCACHE *) zalloc (elm_size);
224
          CPU_SCACHE_CHAIN_LENGTHS (cpu) =
225
            (unsigned long *) zalloc ((CPU_SCACHE_MAX_CHAIN_LENGTH (cpu) + 1)
226
                                      * sizeof (long));
227
#endif
228
        }
229
    }
230
 
231
  scache_flush (sd);
232
 
233
  return SIM_RC_OK;
234
}
235
 
236
static void
237
scache_uninstall (SIM_DESC sd)
238
{
239
  int c;
240
 
241
  for (c = 0; c < MAX_NR_PROCESSORS; ++c)
242
    {
243
      SIM_CPU *cpu = STATE_CPU (sd, c);
244
 
245
      if (CPU_SCACHE_CACHE (cpu) != NULL)
246
        free (CPU_SCACHE_CACHE (cpu));
247
#if WITH_SCACHE_PBB
248
      if (CPU_SCACHE_HASH_TABLE (cpu) != NULL)
249
        free (CPU_SCACHE_HASH_TABLE (cpu));
250
      if (CPU_SCACHE_PBB_BEGIN (cpu) != NULL)
251
        free (CPU_SCACHE_PBB_BEGIN (cpu));
252
      if (CPU_SCACHE_CHAIN_LENGTHS (cpu) != NULL)
253
        free (CPU_SCACHE_CHAIN_LENGTHS (cpu));
254
#endif
255
    }
256
}
257
 
258
void
259
scache_flush (SIM_DESC sd)
260
{
261
  int c;
262
 
263
  for (c = 0; c < MAX_NR_PROCESSORS; ++c)
264
    {
265
      SIM_CPU *cpu = STATE_CPU (sd, c);
266
      scache_flush_cpu (cpu);
267
    }
268
}
269
 
270
void
271
scache_flush_cpu (SIM_CPU *cpu)
272
{
273
  int i,n;
274
 
275
  /* Don't bother if cache not in use.  */
276
  if (CPU_SCACHE_SIZE (cpu) == 0)
277
    return;
278
 
279
#if WITH_SCACHE_PBB
280
  /* It's important that this be reasonably fast as this can be done when
281
     the simulation is running.  */
282
  CPU_SCACHE_NEXT_FREE (cpu) = CPU_SCACHE_CACHE (cpu);
283
  n = CPU_SCACHE_NUM_HASH_CHAINS (cpu) * CPU_SCACHE_NUM_HASH_CHAIN_ENTRIES (cpu);
284
  /* ??? Might be faster to just set the first entry, then update the
285
     "last entry" marker during allocation.  */
286
  for (i = 0; i < n; ++i)
287
    CPU_SCACHE_HASH_TABLE (cpu) [i] . pc = UNUSED_ADDR;
288
#else
289
  {
290
    int elm_size = IMP_PROPS_SCACHE_ELM_SIZE (MACH_IMP_PROPS (CPU_MACH (cpu)));
291
    SCACHE *sc;
292
 
293
    /* Technically, this may not be necessary, but it helps debugging.  */
294
    memset (CPU_SCACHE_CACHE (cpu), 0,
295
            CPU_SCACHE_SIZE (cpu) * elm_size);
296
 
297
    for (i = 0, sc = CPU_SCACHE_CACHE (cpu); i < CPU_SCACHE_SIZE (cpu);
298
         ++i, sc = (SCACHE *) ((char *) sc + elm_size))
299
      {
300
        sc->argbuf.addr = UNUSED_ADDR;
301
      }
302
  }
303
#endif
304
}
305
 
306
#if WITH_SCACHE_PBB
307
 
308
/* Look up PC in the hash table of scache entry points.
309
   Returns the entry or NULL if not found.  */
310
 
311
SCACHE *
312
scache_lookup (SIM_CPU *cpu, IADDR pc)
313
{
314
  /* FIXME: hash computation is wrong, doesn't take into account
315
     NUM_HASH_CHAIN_ENTRIES.  A lot of the hash table will be unused!  */
316
  unsigned int slot = HASH_PC (pc) & (CPU_SCACHE_NUM_HASH_CHAINS (cpu) - 1);
317
  int i, max_i = CPU_SCACHE_NUM_HASH_CHAIN_ENTRIES (cpu);
318
  SCACHE_MAP *scm;
319
 
320
  /* We don't update hit/miss statistics as this is only used when recording
321
     branch target addresses.  */
322
 
323
  scm = & CPU_SCACHE_HASH_TABLE (cpu) [slot];
324
  for (i = 0; i < max_i && scm->pc != UNUSED_ADDR; ++i, ++scm)
325
    {
326
      if (scm->pc == pc)
327
        return scm->sc;
328
    }
329
  return 0;
330
}
331
 
332
/* Look up PC and if not found create an entry for it.
333
   If found the result is a pointer to the SCACHE entry.
334
   If not found the result is NULL, and the address of a buffer of at least
335
   N entries is stored in BUFP.
336
   It's done this way so the caller can still distinguish found/not-found.
337
   If the table is full, it is emptied to make room.
338
   If the maximum length of a hash list is reached a random entry is thrown out
339
   to make room.
340
   ??? One might want to try to make this smarter, but let's see some
341
   measurable benefit first.  */
342
 
343
SCACHE *
344
scache_lookup_or_alloc (SIM_CPU *cpu, IADDR pc, int n, SCACHE **bufp)
345
{
346
  /* FIXME: hash computation is wrong, doesn't take into account
347
     NUM_HASH_CHAIN_ENTRIES.  A lot of the hash table will be unused!  */
348
  unsigned int slot = HASH_PC (pc) & (CPU_SCACHE_NUM_HASH_CHAINS (cpu) - 1);
349
  int i, max_i = CPU_SCACHE_NUM_HASH_CHAIN_ENTRIES (cpu);
350
  SCACHE_MAP *scm;
351
  SCACHE *sc;
352
 
353
  scm = & CPU_SCACHE_HASH_TABLE (cpu) [slot];
354
  for (i = 0; i < max_i && scm->pc != UNUSED_ADDR; ++i, ++scm)
355
    {
356
      if (scm->pc == pc)
357
        {
358
          PROFILE_COUNT_SCACHE_HIT (cpu);
359
          return scm->sc;
360
        }
361
    }
362
  PROFILE_COUNT_SCACHE_MISS (cpu);
363
 
364
  /* The address we want isn't cached.  Bummer.
365
     If the hash chain we have for this address is full, throw out an entry
366
     to make room.  */
367
 
368
  if (i == max_i)
369
    {
370
      /* Rather than do something sophisticated like LRU, we just throw out
371
         a semi-random entry.  Let someone else have the joy of saying how
372
         wrong this is.  NEXT_FREE is the entry to throw out and cycles
373
         through all possibilities.  */
374
      static int next_free = 0;
375
 
376
      scm = & CPU_SCACHE_HASH_TABLE (cpu) [slot];
377
      /* FIXME: This seems rather clumsy.  */
378
      for (i = 0; i < next_free; ++i, ++scm)
379
        continue;
380
      ++next_free;
381
      if (next_free == CPU_SCACHE_NUM_HASH_CHAIN_ENTRIES (cpu))
382
        next_free = 0;
383
    }
384
 
385
  /* At this point SCM points to the hash table entry to use.
386
     Now make sure there's room in the cache.  */
387
  /* FIXME: Kinda weird to use a next_free adjusted scm when cache is
388
     flushed.  */
389
 
390
  {
391
    int elm_size = IMP_PROPS_SCACHE_ELM_SIZE (MACH_IMP_PROPS (CPU_MACH (cpu)));
392
    int elms_used = (((char *) CPU_SCACHE_NEXT_FREE (cpu)
393
                      - (char *) CPU_SCACHE_CACHE (cpu))
394
                     / elm_size);
395
    int elms_left = CPU_SCACHE_SIZE (cpu) - elms_used;
396
 
397
    if (elms_left < n)
398
      {
399
        PROFILE_COUNT_SCACHE_FULL_FLUSH (cpu);
400
        scache_flush_cpu (cpu);
401
      }
402
  }
403
 
404
  sc = CPU_SCACHE_NEXT_FREE (cpu);
405
  scm->pc = pc;
406
  scm->sc = sc;
407
 
408
  *bufp = sc;
409
  return NULL;
410
}
411
 
412
#endif /* WITH_SCACHE_PBB */
413
 
414
/* Print cache access statics for CPU.  */
415
 
416
void
417
scache_print_profile (SIM_CPU *cpu, int verbose)
418
{
419
  SIM_DESC sd = CPU_STATE (cpu);
420
  unsigned long hits = CPU_SCACHE_HITS (cpu);
421
  unsigned long misses = CPU_SCACHE_MISSES (cpu);
422
  char buf[20];
423
  unsigned long max_val;
424
  unsigned long *lengths;
425
  int i;
426
 
427
  if (CPU_SCACHE_SIZE (cpu) == 0)
428
    return;
429
 
430
  sim_io_printf (sd, "Simulator Cache Statistics\n\n");
431
 
432
  /* One could use PROFILE_LABEL_WIDTH here.  I chose not to.  */
433
  sim_io_printf (sd, "  Cache size: %s\n",
434
                 sim_add_commas (buf, sizeof (buf), CPU_SCACHE_SIZE (cpu)));
435
  sim_io_printf (sd, "  Hits:       %s\n",
436
                 sim_add_commas (buf, sizeof (buf), hits));
437
  sim_io_printf (sd, "  Misses:     %s\n",
438
                 sim_add_commas (buf, sizeof (buf), misses));
439
  if (hits + misses != 0)
440
    sim_io_printf (sd, "  Hit rate:   %.2f%%\n",
441
                   ((double) hits / ((double) hits + (double) misses)) * 100);
442
 
443
#if WITH_SCACHE_PBB
444
  sim_io_printf (sd, "\n");
445
  sim_io_printf (sd, "  Hash table size:       %s\n",
446
                 sim_add_commas (buf, sizeof (buf), CPU_SCACHE_NUM_HASH_CHAINS (cpu)));
447
  sim_io_printf (sd, "  Max hash list length:  %s\n",
448
                 sim_add_commas (buf, sizeof (buf), CPU_SCACHE_NUM_HASH_CHAIN_ENTRIES (cpu)));
449
  sim_io_printf (sd, "  Max insn chain length: %s\n",
450
                 sim_add_commas (buf, sizeof (buf), CPU_SCACHE_MAX_CHAIN_LENGTH (cpu)));
451
  sim_io_printf (sd, "  Cache full flushes:    %s\n",
452
                 sim_add_commas (buf, sizeof (buf), CPU_SCACHE_FULL_FLUSHES (cpu)));
453
  sim_io_printf (sd, "\n");
454
 
455
  if (verbose)
456
    {
457
      sim_io_printf (sd, "  Insn chain lengths:\n\n");
458
      max_val = 0;
459
      lengths = CPU_SCACHE_CHAIN_LENGTHS (cpu);
460
      for (i = 1; i < CPU_SCACHE_MAX_CHAIN_LENGTH (cpu); ++i)
461
        if (lengths[i] > max_val)
462
          max_val = lengths[i];
463
      for (i = 1; i < CPU_SCACHE_MAX_CHAIN_LENGTH (cpu); ++i)
464
        {
465
          sim_io_printf (sd, "  %2d: %*s: ",
466
                         i,
467
                         max_val < 10000 ? 5 : 10,
468
                         sim_add_commas (buf, sizeof (buf), lengths[i]));
469
          sim_profile_print_bar (sd, cpu, PROFILE_HISTOGRAM_WIDTH,
470
                                 lengths[i], max_val);
471
          sim_io_printf (sd, "\n");
472
        }
473
      sim_io_printf (sd, "\n");
474
    }
475
#endif /* WITH_SCACHE_PBB */
476
}

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