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1996-05-08 * breakpoint.c (clear_momentary_breakpoints): Remove dead codeFred Fish4-174/+77
1996-05-08 * config/abug.exp: New file for the older Motorola Bug monitorRob Savoye3-10/+32
1996-05-08 * target.c (debug_to_xfer_memory): Insert line breaks whenStan Shebs1-0/+5
1996-05-06 * fork-child.c (fork_inferior), inferior.h: init_trace_fun nowStu Grossman12-271/+1962
1996-05-06Do not do XCOFF hoooks for ELF systemsMichael Meissner2-9/+17
1996-05-03 * sim-gdb.exp: Make the SH simulator allocate less space whenStan Shebs2-1/+17
1996-05-03 * gdbtk.tcl (debug_interface): New global, use to aid debugging.Stan Shebs2-56/+84
1996-05-02 * From Peter Schauer:Jeff Law3-81/+179
1996-05-02 * gdb.base/mips_pro.exp: Expect failure for hppa*-*-* in backtraceJeff Law1-0/+20
1996-05-02 * Makefile.in (rs6000-nat.o): Dependant on xcoffsolib.h.Fred Fish7-17/+69
1996-04-30Add bieginning of Solaris/PowerPC supportMichael Meissner7-1/+143
1996-04-29 * c-valprint.c (c_val_print): Fix printing for arrays definedDawn Perchik2-0/+6
1996-04-28 Support for bi-endian remote breakpoints.Stan Shebs3-14/+67
1996-04-28 * mon960-rom.c (mon960_cmds): Remove forward decl.Stan Shebs2-12/+17
1996-04-28 * symfile.h (psymbol_allocation_list): Expand comments whichFred Fish1-0/+6
1996-04-28 * breakpoint.c (delete_breakpoint): Fix bpt->val, bpt->expPeter Schauer3-5/+31
1996-04-28 * Makefile.in (CLIBS): Move $(MMALLOC) past all other libs,Fred Fish2-6/+17
1996-04-28Fix typo in ChangeLog entry.Jeff Law1-1/+1
1996-04-28Remove some #if 0 code which creeped into wait_for_inferior duringJeff Law1-4/+0
1996-04-27 * stabsread.c: Changes and bug fixes for cfront support.Dawn Perchik2-12/+204
1996-04-27 * infrun.c (wait_for_inferior): Call registers_changed whenJeff Law2-0/+12
1996-04-24 Forgot to checkin ChangeLog with last checkin for cfront support.Dawn Perchik1-0/+4
1996-04-24 Add new support for parsing cfront stabs.Dawn Perchik4-16/+814
1996-04-24 * infrun.c (wait_for_inferior): Move "have_waited" labelJeff Law2-5/+36
1996-04-23 * Makefile.in (VERSION): Bump version number to 4.16.1Fred Fish1-28/+83
1996-04-22 * monitor.h: Clean up comment formatting.Stan Shebs3-100/+98
1996-04-22Consistently use address <fnf@cygnus.com> for entries.Fred Fish1-5/+5
1996-04-22 * corefile.c (specify_exec_file_hook): Allow arbitrary number ofMark Alexander3-11/+91
1996-04-19 * remote-mips.c (encoding): Don't specify size, to avoid bug inIan Lance Taylor2-1/+6
1996-04-19 * monitor.c: Use int rather than LONGEST for values, sinceStan Shebs2-61/+126
1996-04-18 * arm-tdep.c (initialize_arm_tdep): Make apcs32 a `zinteger'.David Edelsohn1-0/+4
1996-04-17 * tests1.{ch,exp}: Tets case modified and enhanced.Wilfried Moser3-8/+26
1996-04-17 * corelow.c (add_to_thread_list): Make sure reg_sect is non-nullStu Grossman3-3/+21
1996-04-15 * stabsread.c (read_type): Move handling of '@' from typePer Bothner2-104/+80
1996-04-15 * ch-exp.c (calculate_array_length): Fix prototype.Jeff Law2-1/+5
1996-04-13 * remote-nindy.c (nindy_open): Acquire more target state so thatStu Grossman5-29/+47
1996-04-13 * eval.c (evaluate_subexp_standard): Report error when attempting toPeter Schauer1-0/+17
1996-04-13 * README: Update for 4.16 release.Fred Fish5-2/+20
1996-04-12 * defs.h: Define TARGET_{FLOAT DOUBLE LONG_DOUBLE}_FORMATStu Grossman4-44/+35
1996-04-12 * config/nm-m3.h (ATTACH_NO_WAIT): Define.Fred Fish1-0/+3
1996-04-12 From: Miles Bader <miles@gnu.ai.mit.edu>Fred Fish6-68/+246
1996-04-12 * remote.c (remotewritesize): New GDB variable, controls sizeStan Shebs1-0/+5
1996-04-11 * dcache.c: Add prototypes. Make many functions static.Stu Grossman7-66/+551
1996-04-10 * ch-valprint.c (chill_val_print): Remove call to calculate_array_len...Wilfried Moser3-52/+67
1996-04-09 * eval.c (evaluate_subexp_standard): In case of TYPE_CODE_SET:Wilfried Moser2-0/+35
1996-04-09 * gch981.{ch,exp}, gch1041.{ch,exp}: New test cases.Wilfried Moser6-0/+410
1996-04-09 * Makefile.in (scm-exp.o, scm-lang.o, scm-valprint.o): Add targets andFred Fish8-16/+45
1996-04-08 * infptrace.c (kill_inferior): Remove call to "kill"; updateJeff Law1-0/+5
1996-04-08Modified remote-e7000.c so that :23 isn't appended to the target portGeoffrey Noer1-0/+5
1996-04-08 From: Miles Bader <miles@gnu.ai.mit.edu>Fred Fish17-1/+3594
generated by cgit v1.1 at 2025-02-21 19:36:38 +0000
are; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */ #include "defs.h" #include "dcache.h" #include "gdbcmd.h" #include "gdb_string.h" #include "gdbcore.h" #include "target.h" /* The data cache could lead to incorrect results because it doesn't know about volatile variables, thus making it impossible to debug functions which use memory mapped I/O devices. Set the nocache memory region attribute in those cases. In general the dcache speeds up performance, some speed improvement comes from the actual caching mechanism, but the major gain is in the reduction of the remote protocol overhead; instead of reading or writing a large area of memory in 4 byte requests, the cache bundles up the requests into 32 byte (actually LINE_SIZE) chunks. Reducing the overhead to an eighth of what it was. This is very obvious when displaying a large amount of data, eg, x/200x 0 caching | no yes ---------------------------- first time | 4 sec 2 sec improvement due to chunking second time | 4 sec 0 sec improvement due to caching The cache structure is unusual, we keep a number of cache blocks (DCACHE_SIZE) and each one caches a LINE_SIZEed area of memory. Within each line we remember the address of the line (always a multiple of the LINE_SIZE) and a vector of bytes over the range. There's another vector which contains the state of the bytes. ENTRY_BAD means that the byte is just plain wrong, and has no correspondence with anything else (as it would when the cache is turned on, but nothing has been done to it. ENTRY_DIRTY means that the byte has some data in it which should be written out to the remote target one day, but contains correct data. ENTRY_OK means that the data is the same in the cache as it is in remote memory. The ENTRY_DIRTY state is necessary because GDB likes to write large lumps of memory in small bits. If the caching mechanism didn't maintain the DIRTY information, then something like a two byte write would mean that the entire cache line would have to be read, the two bytes modified and then written out again. The alternative would be to not read in the cache line in the first place, and just write the two bytes directly into target memory. The trouble with that is that it really nails performance, because of the remote protocol overhead. This way, all those little writes are bundled up into an entire cache line write in one go, without having to read the cache line in the first place. */ /* NOTE: Interaction of dcache and memory region attributes As there is no requirement that memory region attributes be aligned to or be a multiple of the dcache page size, dcache_read_line() and dcache_write_line() must break up the page by memory region. If a chunk does not have the cache attribute set, an invalid memory type is set, etc., then the chunk is skipped. Those chunks are handled in target_xfer_memory() (or target_xfer_memory_partial()). This doesn't occur very often. The most common occurance is when the last bit of the .text segment and the first bit of the .data segment fall within the same dcache page with a ro/cacheable memory region defined for the .text segment and a rw/non-cacheable memory region defined for the .data segment. */ /* This value regulates the number of cache blocks stored. Smaller values reduce the time spent searching for a cache line, and reduce memory requirements, but increase the risk of a line not being in memory */ #define DCACHE_SIZE 64 /* This value regulates the size of a cache line. Smaller values reduce the time taken to read a single byte, but reduce overall throughput. */ #define LINE_SIZE_POWER (5) #define LINE_SIZE (1 << LINE_SIZE_POWER) /* Each cache block holds LINE_SIZE bytes of data starting at a multiple-of-LINE_SIZE address. */ #define LINE_SIZE_MASK ((LINE_SIZE - 1)) #define XFORM(x) ((x) & LINE_SIZE_MASK) #define MASK(x) ((x) & ~LINE_SIZE_MASK) #define ENTRY_BAD 0 /* data at this byte is wrong */ #define ENTRY_DIRTY 1 /* data at this byte needs to be written back */ #define ENTRY_OK 2 /* data at this byte is same as in memory */ struct dcache_block { struct dcache_block *p; /* next in list */ CORE_ADDR addr; /* Address for which data is recorded. */ char data[LINE_SIZE]; /* bytes at given address */ unsigned char state[LINE_SIZE]; /* what state the data is in */ /* whether anything in state is dirty - used to speed up the dirty scan. */ int anydirty; int refs; }; /* FIXME: dcache_struct used to have a cache_has_stuff field that was used to record whether the cache had been accessed. This was used to invalidate the cache whenever caching was (re-)enabled (if the cache was disabled and later re-enabled, it could contain stale data). This was not needed because the cache is write through and the code that enables, disables, and deletes memory region all invalidate the cache. This is overkill, since it also invalidates cache lines from unrelated regions. One way this could be addressed by adding a new function that takes an address and a length and invalidates only those cache lines that match. */ struct dcache_struct { /* free list */ struct dcache_block *free_head; struct dcache_block *free_tail; /* in use list */ struct dcache_block *valid_head; struct dcache_block *valid_tail; /* The cache itself. */ struct dcache_block *the_cache; }; static int dcache_poke_byte (DCACHE *dcache, CORE_ADDR addr, char *ptr); static int dcache_peek_byte (DCACHE *dcache, CORE_ADDR addr, char *ptr); static struct dcache_block *dcache_hit (DCACHE *dcache, CORE_ADDR addr); static int dcache_write_line (DCACHE *dcache, struct dcache_block *db); static int dcache_read_line (DCACHE *dcache, struct dcache_block *db); static struct dcache_block *dcache_alloc (DCACHE *dcache, CORE_ADDR addr); static int dcache_writeback (DCACHE *dcache); static void dcache_info (char *exp, int tty); void _initialize_dcache (void); static int dcache_enabled_p = 0; DCACHE *last_cache; /* Used by info dcache */ /* Free all the data cache blocks, thus discarding all cached data. */ void dcache_invalidate (DCACHE *dcache) { int i; dcache->valid_head = 0; dcache->valid_tail = 0; dcache->free_head = 0; dcache->free_tail = 0; for (i = 0; i < DCACHE_SIZE; i++) { struct dcache_block *db = dcache->the_cache + i; if (!dcache->free_head) dcache->free_head = db; else dcache->free_tail->p = db; dcache->free_tail = db; db->p = 0; } return; } /* If addr is present in the dcache, return the address of the block containing it. */ static struct dcache_block * dcache_hit (DCACHE *dcache, CORE_ADDR addr) { register struct dcache_block *db; /* Search all cache blocks for one that is at this address. */ db = dcache->valid_head; while (db) { if (MASK (addr) == db->addr) { db->refs++; return db; } db = db->p; } return NULL; } /* Make sure that anything in this line which needs to be written is. */ static int dcache_write_line (DCACHE *dcache, register struct dcache_block *db) { CORE_ADDR memaddr; char *myaddr; int len; int res; int reg_len; struct mem_region *region; if (!db->anydirty) return 1; len = LINE_SIZE; memaddr = db->addr; myaddr = db->data; while (len > 0) { int s; int e; int dirty_len; region = lookup_mem_region(memaddr); if (memaddr + len < region->hi) reg_len = len; else reg_len = region->hi - memaddr; if (!region->attrib.cache || region->attrib.mode == MEM_RO) { memaddr += reg_len; myaddr += reg_len; len -= reg_len; continue; } while (reg_len > 0) { s = XFORM(memaddr); while (reg_len > 0) { if (db->state[s] == ENTRY_DIRTY) break; s++; reg_len--; memaddr++; myaddr++; len--; } e = s; while (reg_len > 0) { if (db->state[e] != ENTRY_DIRTY) break; e++; reg_len--; } dirty_len = e - s; while (dirty_len > 0) { res = do_xfer_memory(memaddr, myaddr, dirty_len, 1, &region->attrib); if (res <= 0) return 0; memset (&db->state[XFORM(memaddr)], ENTRY_OK, res); memaddr += res; myaddr += res; len -= res; dirty_len -= res; } } } db->anydirty = 0; return 1; } /* Read cache line */ static int dcache_read_line (DCACHE *dcache, struct dcache_block *db) { CORE_ADDR memaddr; char *myaddr; int len; int res; int reg_len; struct mem_region *region; /* If there are any dirty bytes in the line, it must be written before a new line can be read */ if (db->anydirty) { if (!dcache_write_line (dcache, db)) return 0; } len = LINE_SIZE; memaddr = db->addr; myaddr = db->data; while (len > 0) { region = lookup_mem_region(memaddr); if (memaddr + len < region->hi) reg_len = len; else reg_len = region->hi - memaddr; if (!region->attrib.cache || region->attrib.mode == MEM_WO) { memaddr += reg_len; myaddr += reg_len; len -= reg_len; continue; } while (reg_len > 0) { res = do_xfer_memory (memaddr, myaddr, reg_len, 0, &region->attrib); if (res <= 0) return 0; memaddr += res; myaddr += res; len -= res; reg_len -= res; } } memset (db->state, ENTRY_OK, sizeof (db->data)); db->anydirty = 0; return 1; } /* Get a free cache block, put or keep it on the valid list, and return its address. */ static struct dcache_block * dcache_alloc (DCACHE *dcache, CORE_ADDR addr) { register struct dcache_block *db; /* Take something from the free list */ db = dcache->free_head; if (db) { dcache->free_head = db->p; } else { /* Nothing left on free list, so grab one from the valid list */ db = dcache->valid_head; if (!dcache_write_line (dcache, db)) return NULL; dcache->valid_head = db->p; } db->addr = MASK(addr); db->refs = 0; db->anydirty = 0; memset (db->state, ENTRY_BAD, sizeof (db->data)); /* append this line to end of valid list */ if (!dcache->valid_head) dcache->valid_head = db; else dcache->valid_tail->p = db; dcache->valid_tail = db; db->p = 0; return db; } /* Writeback any dirty lines. */ static int dcache_writeback (DCACHE *dcache) { struct dcache_block *db; db = dcache->valid_head; while (db) { if (!dcache_write_line (dcache, db)) return 0; db = db->p; } return 1; } /* Using the data cache DCACHE return the contents of the byte at address ADDR in the remote machine. Returns 0 on error. */ static int dcache_peek_byte (DCACHE *dcache, CORE_ADDR addr, char *ptr) { register struct dcache_block *db = dcache_hit (dcache, addr); if (!db) { db = dcache_alloc (dcache, addr); if (!db) return 0; } if (db->state[XFORM (addr)] == ENTRY_BAD) { if (!dcache_read_line(dcache, db)) return 0; } *ptr = db->data[XFORM (addr)]; return 1; } /* Write the byte at PTR into ADDR in the data cache. Return zero on write error. */ static int dcache_poke_byte (DCACHE *dcache, CORE_ADDR addr, char *ptr) { register struct dcache_block *db = dcache_hit (dcache, addr); if (!db) { db = dcache_alloc (dcache, addr); if (!db) return 0; } db->data[XFORM (addr)] = *ptr; db->state[XFORM (addr)] = ENTRY_DIRTY; db->anydirty = 1; return 1; } /* Initialize the data cache. */ DCACHE * dcache_init (void) { int csize = sizeof (struct dcache_block) * DCACHE_SIZE; DCACHE *dcache; dcache = (DCACHE *) xmalloc (sizeof (*dcache)); dcache->the_cache = (struct dcache_block *) xmalloc (csize); memset (dcache->the_cache, 0, csize); dcache_invalidate (dcache); last_cache = dcache; return dcache; } /* Free a data cache */ void dcache_free (DCACHE *dcache) { if (last_cache == dcache) last_cache = NULL; xfree (dcache->the_cache); xfree (dcache); } /* Read or write LEN bytes from inferior memory at MEMADDR, transferring to or from debugger address MYADDR. Write to inferior if SHOULD_WRITE is nonzero. Returns length of data written or read; 0 for error. This routine is indended to be called by remote_xfer_ functions. */ int dcache_xfer_memory (DCACHE *dcache, CORE_ADDR memaddr, char *myaddr, int len, int should_write) { int i; int (*xfunc) (DCACHE *dcache, CORE_ADDR addr, char *ptr); xfunc = should_write ? dcache_poke_byte : dcache_peek_byte; for (i = 0; i < len; i++) { if (!xfunc (dcache, memaddr + i, myaddr + i)) return 0; } /* FIXME: There may be some benefit from moving the cache writeback to a higher layer, as it could occur after a sequence of smaller writes have been completed (as when a stack frame is constructed for an inferior function call). Note that only moving it up one level to target_xfer_memory() (also target_xfer_memory_partial()) is not sufficent, since we want to coalesce memory transfers that are "logically" connected but not actually a single call to one of the memory transfer functions. */ if (should_write) dcache_writeback (dcache); return len; } static void dcache_info (char *exp, int tty) { struct dcache_block *p; printf_filtered ("Dcache line width %d, depth %d\n", LINE_SIZE, DCACHE_SIZE); if (last_cache) { printf_filtered ("Cache state:\n"); for (p = last_cache->valid_head; p; p = p->p) { int j; printf_filtered ("Line at %s, referenced %d times\n", paddr (p->addr), p->refs); for (j = 0; j < LINE_SIZE; j++) printf_filtered ("%02x", p->data[j] & 0xFF); printf_filtered ("\n"); for (j = 0; j < LINE_SIZE; j++) printf_filtered ("%2x", p->state[j]); printf_filtered ("\n"); } } } void _initialize_dcache (void) { add_show_from_set (add_set_cmd ("remotecache", class_support, var_boolean, (char *) &dcache_enabled_p, "\ Set cache use for remote targets.\n\ When on, use data caching for remote targets. For many remote targets\n\ this option can offer better throughput for reading target memory.\n\ Unfortunately, gdb does not currently know anything about volatile\n\ registers and thus data caching will produce incorrect results with\n\ volatile registers are in use. By default, this option is off.", &setlist), &showlist); add_info ("dcache", dcache_info, "Print information on the dcache performance."); }
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