diff options
Diffstat (limited to 'elf/dl-profile.c')
| -rw-r--r-- | elf/dl-profile.c | 167 |
1 files changed, 133 insertions, 34 deletions
diff --git a/elf/dl-profile.c b/elf/dl-profile.c index c8028a7..9b020e8 100644 --- a/elf/dl-profile.c +++ b/elf/dl-profile.c @@ -2,6 +2,7 @@ Copyright (C) 1997 Free Software Foundation, Inc. This file is part of the GNU C Library. Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997. + Based on the BSD mcount implementation. The GNU C Library is free software; you can redistribute it and/or modify it under the terms of the GNU Library General Public License as @@ -30,6 +31,7 @@ #include <sys/gmon_out.h> #include <sys/mman.h> #include <sys/stat.h> +#include <atomicity.h> /* The LD_PROFILE feature has to be implemented different to the normal profiling using the gmon/ functions. The problem is that an @@ -146,19 +148,19 @@ static long int state; static volatile uint16_t *kcount; static size_t kcountsize; -struct here_tostruct +struct here_fromstruct { struct here_cg_arc_record volatile *here; uint16_t link; }; -static uint16_t *froms; -static size_t fromssize; - -static struct here_tostruct *tos; +static uint16_t *tos; static size_t tossize; -static size_t tolimit; -static size_t toidx; + +static struct here_fromstruct *froms; +static size_t fromssize; +static size_t fromlimit; +static size_t fromidx; static uintptr_t lowpc; static uintptr_t highpc; @@ -170,6 +172,11 @@ static unsigned int log_hashfraction; static struct gmon_hdr *addr; static off_t expected_size; +/* See profil(2) where this is described. */ +static int s_scale; +#define SCALE_1_TO_1 0x10000L + + /* Set up profiling data to profile object desribed by MAP. The output file is found (or created) in OUTPUT_DIR. */ @@ -184,7 +191,7 @@ _dl_start_profile (struct link_map *map, const char *output_dir) ElfW(Addr) mapend = 0; struct gmon_hdr gmon_hdr; struct gmon_hist_hdr hist_hdr; - char *hist; + char *hist, *cp; size_t idx; /* Compute the size of the sections which contain program code. */ @@ -205,9 +212,9 @@ _dl_start_profile (struct link_map *map, const char *output_dir) with the same formulars as in `monstartup' (see gmon.c). */ state = GMON_PROF_OFF; lowpc = ROUNDDOWN (mapstart + map->l_addr, - HISTFRACTION * sizeof(HISTCOUNTER)); + HISTFRACTION * sizeof (HISTCOUNTER)); highpc = ROUNDUP (mapend + map->l_addr, - HISTFRACTION * sizeof(HISTCOUNTER)); + HISTFRACTION * sizeof (HISTCOUNTER)); textsize = highpc - lowpc; kcountsize = textsize / HISTFRACTION; hashfraction = HASHFRACTION; @@ -217,17 +224,17 @@ _dl_start_profile (struct link_map *map, const char *output_dir) log_hashfraction = __builtin_ffs (hashfraction * sizeof (*froms)) - 1; else log_hashfraction = -1; - fromssize = textsize / HASHFRACTION; - tolimit = textsize * ARCDENSITY / 100; - if (tolimit < MINARCS) - tolimit = MINARCS; - if (tolimit > MAXARCS) - tolimit = MAXARCS; - tossize = tolimit * sizeof (struct here_tostruct); + tossize = textsize / HASHFRACTION; + fromlimit = textsize * ARCDENSITY / 100; + if (fromlimit < MINARCS) + fromlimit = MINARCS; + if (fromlimit > MAXARCS) + fromlimit = MAXARCS; + fromssize = fromlimit * sizeof (struct here_fromstruct); expected_size = (sizeof (struct gmon_hdr) + 4 + sizeof (struct gmon_hist_hdr) + kcountsize - + 4 + 4 + tossize * sizeof (struct here_cg_arc_record)); + + 4 + 4 + fromssize * sizeof (struct here_cg_arc_record)); /* Create the gmon_hdr we expect or write. */ memset (&gmon_hdr, '\0', sizeof (struct gmon_hdr)); @@ -247,9 +254,9 @@ _dl_start_profile (struct link_map *map, const char *output_dir) soname (or the file name) and the ending ".profile". */ filename = (char *) alloca (strlen (output_dir) + 1 + strlen (_dl_profile) + sizeof ".profile"); - __stpcpy (__stpcpy (__stpcpy (__stpcpy (filename, output_dir), "/"), - _dl_profile), - ".profile"); + cp = __stpcpy (filename, output_dir); + *cp++ = '/'; + __stpcpy (__stpcpy (cp, _dl_profile), ".profile"); fd = __open (filename, O_RDWR | O_CREAT, 0666); if (fd == -1) @@ -356,7 +363,7 @@ _dl_start_profile (struct link_map *map, const char *output_dir) } /* Allocate memory for the froms data and the pointer to the tos records. */ - froms = (uint16_t *) calloc (fromssize + tossize, 1); + tos = (uint16_t *) calloc (tossize + fromssize, 1); if (froms == NULL) { __munmap ((void *) addr, expected_size); @@ -364,8 +371,8 @@ _dl_start_profile (struct link_map *map, const char *output_dir) /* NOTREACHED */ } - tos = (struct here_tostruct *) ((char *) froms + fromssize); - toidx = 0; + froms = (struct here_fromstruct *) ((char *) tos + tossize); + fromidx = 0; /* Now we have to process all the arc count entries. BTW: it is not critical whether the *NARCSP value changes meanwhile. Before @@ -376,17 +383,26 @@ _dl_start_profile (struct link_map *map, const char *output_dir) frequently used entries at the front of the list. */ for (idx = narcs = *narcsp; idx > 0; ) { - size_t from_index; - size_t newtoidx; + size_t to_index; + size_t newfromidx; --idx; - from_index = ((data[idx].from_pc - lowpc) - / (hashfraction * sizeof (*froms))); - newtoidx = toidx++; - tos[newtoidx].here = &data[idx]; - tos[newtoidx].link = froms[from_index]; - froms[from_index] = newtoidx; + to_index = ((data[idx].self_pc - lowpc) + / (hashfraction * sizeof (*tos))); + newfromidx = fromidx++; + froms[newfromidx].here = &data[idx]; + froms[newfromidx].link = tos[to_index]; + tos[to_index] = newfromidx; } + /* Setup counting data. */ + if (kcountsize < highpc - lowpc) + s_scale = ((double) kcountsize / (highpc - lowpc)) * SCALE_1_TO_1; + else + s_scale = SCALE_1_TO_1; + + /* Start the profiler. */ + __profil ((void *) kcount, kcountsize, lowpc, s_scale); + /* Turn on profiling. */ state = GMON_PROF_ON; } @@ -395,9 +411,12 @@ _dl_start_profile (struct link_map *map, const char *output_dir) void _dl_mcount (ElfW(Addr) frompc, ElfW(Addr) selfpc) { - if (state != GMON_PROF_ON) + uint16_t *topcindex; + size_t i, fromindex; + struct here_fromstruct *fromp; + + if (! compare_and_swap (&state, GMON_PROF_ON, GMON_PROF_BUSY)) return; - state = GMON_PROF_BUSY; /* Compute relative addresses. The shared object can be loaded at any address. The value of frompc could be anything. We cannot @@ -411,6 +430,86 @@ _dl_mcount (ElfW(Addr) frompc, ElfW(Addr) selfpc) if (selfpc >= textsize) goto done; + /* Getting here we now have to find out whether the location was + already used. If yes we are lucky and only have to increment a + counter (this also has to be atomic). If the entry is new things + are getting complicated... */ + + /* Avoid integer divide if possible. */ + if ((HASHFRACTION & (HASHFRACTION - 1)) == 0) + i = selfpc >> log_hashfraction; + else + i = selfpc / (hashfraction * sizeof (*tos)); + + topcindex = &tos[i]; + fromindex = *topcindex; + + if (fromindex == 0) + goto check_new_or_add; + + fromp = &froms[fromindex]; + + /* We have to look through the chain of arcs whether there is already + an entry for our arc. */ + while (fromp->here->from_pc == frompc) + { + if (fromp->link != 0) + do + fromp = &froms[fromp->link]; + while (fromp->link != 0 && fromp->here->from_pc != frompc); + + if (fromp->link == 0) + { + topcindex = &fromp->link; + + check_new_or_add: + /* Our entry is not among the entries we read so far from the + data file. Now see whether we have to update the list. */ + while (narcs != *narcsp) + { + size_t to_index; + size_t newfromidx; + to_index = ((data[narcs].self_pc - lowpc) + / (hashfraction * sizeof (*tos))); + newfromidx = fromidx++; + froms[newfromidx].here = &data[narcs]; + froms[newfromidx].link = tos[to_index]; + tos[to_index] = newfromidx; + ++narcs; + } + + /* If we still have no entry stop searching and insert. */ + if (*topcindex == 0) + { + fromidx = 1 + exchange_and_add (narcsp, 1); + ++narcs; + + /* In rare cases it could happen that all entries in FROMS are + occupied. So we cannot count this anymore. */ + if (fromidx >= fromlimit) + goto done; + + *topcindex = fromindex; + fromp = &froms[fromindex]; + + fromp = &froms[fromp->link]; + + fromp->link = 0; + fromp->here->from_pc = frompc; + fromp->here->count = 0; + + break; + } + + fromp = &froms[*topcindex]; + } + else + /* Found in. */ + break; + } + + /* Increment the counter. */ + atomic_add (&fromp->here->count, 1); done: state = GMON_PROF_ON; |