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[trace] Simple unbounded cache for symbol lookups.

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Reparsing the dwarf info for every lookup is very slow, so cache the
symbol lookups. This initial implementation is unbounded in the simple
belief that the actual number of unique lookups during a program's
lifetime should be fairly small. (Extending to a bounded MRU list is left
as an exercise for the reader.)
This commit is contained in:
Chris Wilson 2008-11-18 00:32:54 +00:00
parent 2839a0e800
commit 91c17d3332
2 changed files with 64 additions and 13 deletions
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68
util/cairo-trace/lookup-symbol.c
View file

@ -61,6 +61,7 @@
#include <stdlib.h>
#include <link.h>
#include <string.h>
#include <pthread.h>
#if HAVE_BFD
#include <bfd.h>
@ -246,6 +247,15 @@ find_matching_file (struct dl_phdr_info *info, size_t size, void *data)
return 0;
}
struct symbol_cache_entry {
const void *ptr;
struct symbol_cache_entry *hash_prev, *hash_next;
char name[0];
};
static struct symbol_cache_entry *symbol_cache_hash[13477];
static pthread_mutex_t symbol_cache_mutex = PTHREAD_MUTEX_INITIALIZER;
char *
lookup_symbol (char *buf, int buflen, const void *ptr)
{
@ -254,6 +264,32 @@ lookup_symbol (char *buf, int buflen, const void *ptr)
struct symtab symtab;
struct symbol symbol;
#endif
struct symbol_cache_entry *cache;
int bucket;
int len;
bucket = (unsigned long) ptr % (sizeof (symbol_cache_hash) / sizeof (symbol_cache_hash[0]));
pthread_mutex_lock (&symbol_cache_mutex);
for (cache = symbol_cache_hash[bucket];
cache != NULL;
cache = cache->hash_next)
{
if (cache->ptr == ptr) {
if (cache->hash_prev != NULL) {
cache->hash_prev->hash_next = cache->hash_next;
if (cache->hash_next != NULL)
cache->hash_next->hash_prev = cache->hash_prev;
cache->hash_prev = NULL;
cache->hash_next = symbol_cache_hash[bucket];
symbol_cache_hash[bucket]->hash_prev = cache;
symbol_cache_hash[bucket] = cache;
}
pthread_mutex_unlock (&symbol_cache_mutex);
return cache->name;
}
}
pthread_mutex_unlock (&symbol_cache_mutex);
match.file = NULL;
match.address = (ElfW(Addr)) ptr;
@ -266,17 +302,31 @@ lookup_symbol (char *buf, int buflen, const void *ptr)
match.file = "/proc/self/exe";
#if HAVE_BFD
if (! _symtab_init (&symtab, match.file))
return buf;
if (_symtab_init (&symtab, match.file)) {
_symbol_init (&symbol, &symtab, match.address - match.base);
bfd_map_over_sections (symtab.bfd, find_address_in_section, &symbol);
if (symbol.found)
_symbol_print (&symbol, buf, buflen, match.file);
_symbol_fini (&symbol);
_symbol_init (&symbol, &symtab, match.address - match.base);
bfd_map_over_sections (symtab.bfd, find_address_in_section, &symbol);
if (symbol.found)
_symbol_print (&symbol, buf, buflen, match.file);
_symbol_fini (&symbol);
_symtab_fini (&symtab);
_symtab_fini (&symtab);
}
#endif
len = strlen (buf);
cache = malloc (sizeof (struct symbol_cache_entry) + len + 1);
if (cache != NULL) {
cache->ptr = ptr;
memcpy (cache->name, buf, len + 1);
pthread_mutex_lock (&symbol_cache_mutex);
cache->hash_prev = NULL;
cache->hash_next = symbol_cache_hash[bucket];
if (symbol_cache_hash[bucket] != NULL)
symbol_cache_hash[bucket]->hash_prev = cache;
symbol_cache_hash[bucket] = cache;
pthread_mutex_unlock (&symbol_cache_mutex);
}
return buf;
}

9
util/cairo-trace/trace.c
View file

@ -157,8 +157,8 @@ static const cairo_user_data_key_t destroy_key;
if (_line_info && _write_lock ()) { \
void *addr = __builtin_return_address(0); \
char caller[1024]; \
lookup_symbol (caller, sizeof (caller), addr); \
fprintf (logfile, "%% %s() called by %s\n", __FUNCTION__, caller); \
fprintf (logfile, "%% %s() called by %s\n", __FUNCTION__, \
lookup_symbol (caller, sizeof (caller), addr)); \
_write_unlock (); \
} \
} while (0)
@ -2983,8 +2983,9 @@ cairo_surface_write_to_png_stream (cairo_surface_t *surface,
char symbol[1024];
fprintf (logfile, "%% s%ld ", _get_surface_id (surface));
lookup_symbol (symbol, sizeof (symbol), write_func);
_emit_string_literal (symbol, -1);
_emit_string_literal (lookup_symbol (symbol, sizeof (symbol),
write_func),
-1);
fprintf (logfile, " write_to_png_stream\n");
_write_unlock ();
}