mirror of https://gitee.com/Nocallback/glibc.git
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
542 lines
17 KiB
542 lines
17 KiB
/* Profiling of shared libraries.
|
|
Copyright (C) 1997, 1998, 1999, 2000 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
|
|
published by the Free Software Foundation; either version 2 of the
|
|
License, or (at your option) any later version.
|
|
|
|
The GNU C Library 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
|
|
Library General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Library General Public
|
|
License along with the GNU C Library; see the file COPYING.LIB. If not,
|
|
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
|
|
Boston, MA 02111-1307, USA. */
|
|
|
|
#include <errno.h>
|
|
#include <fcntl.h>
|
|
#include <inttypes.h>
|
|
#include <limits.h>
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <string.h>
|
|
#include <unistd.h>
|
|
#include <ldsodefs.h>
|
|
#include <sys/gmon.h>
|
|
#include <sys/gmon_out.h>
|
|
#include <sys/mman.h>
|
|
#include <sys/param.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
|
|
arbitrary amount of processes simulataneously can be run using
|
|
profiling and all write the results in the same file. To provide
|
|
this mechanism one could implement a complicated mechanism to merge
|
|
the content of two profiling runs or one could extend the file
|
|
format to allow more than one data set. For the second solution we
|
|
would have the problem that the file can grow in size beyond any
|
|
limit and both solutions have the problem that the concurrency of
|
|
writing the results is a big problem.
|
|
|
|
Another much simpler method is to use mmap to map the same file in
|
|
all using programs and modify the data in the mmap'ed area and so
|
|
also automatically on the disk. Using the MAP_SHARED option of
|
|
mmap(2) this can be done without big problems in more than one
|
|
file.
|
|
|
|
This approach is very different from the normal profiling. We have
|
|
to use the profiling data in exactly the way they are expected to
|
|
be written to disk. But the normal format used by gprof is not usable
|
|
to do this. It is optimized for size. It writes the tags as single
|
|
bytes but this means that the following 32/64 bit values are
|
|
unaligned.
|
|
|
|
Therefore we use a new format. This will look like this
|
|
|
|
0 1 2 3 <- byte is 32 bit word
|
|
0000 g m o n
|
|
0004 *version* <- GMON_SHOBJ_VERSION
|
|
0008 00 00 00 00
|
|
000c 00 00 00 00
|
|
0010 00 00 00 00
|
|
|
|
0014 *tag* <- GMON_TAG_TIME_HIST
|
|
0018 ?? ?? ?? ??
|
|
?? ?? ?? ?? <- 32/64 bit LowPC
|
|
0018+A ?? ?? ?? ??
|
|
?? ?? ?? ?? <- 32/64 bit HighPC
|
|
0018+2*A *histsize*
|
|
001c+2*A *profrate*
|
|
0020+2*A s e c o
|
|
0024+2*A n d s \0
|
|
0028+2*A \0 \0 \0 \0
|
|
002c+2*A \0 \0 \0
|
|
002f+2*A s
|
|
|
|
0030+2*A ?? ?? ?? ?? <- Count data
|
|
... ...
|
|
0030+2*A+K ?? ?? ?? ??
|
|
|
|
0030+2*A+K *tag* <- GMON_TAG_CG_ARC
|
|
0034+2*A+K *lastused*
|
|
0038+2*A+K ?? ?? ?? ??
|
|
?? ?? ?? ?? <- FromPC#1
|
|
0038+3*A+K ?? ?? ?? ??
|
|
?? ?? ?? ?? <- ToPC#1
|
|
0038+4*A+K ?? ?? ?? ?? <- Count#1
|
|
... ... ...
|
|
0038+(2*(CN-1)+2)*A+(CN-1)*4+K ?? ?? ?? ??
|
|
?? ?? ?? ?? <- FromPC#CGN
|
|
0038+(2*(CN-1)+3)*A+(CN-1)*4+K ?? ?? ?? ??
|
|
?? ?? ?? ?? <- ToPC#CGN
|
|
0038+(2*CN+2)*A+(CN-1)*4+K ?? ?? ?? ?? <- Count#CGN
|
|
|
|
We put (for now?) no basic block information in the file since this would
|
|
introduce rase conditions among all the processes who want to write them.
|
|
|
|
`K' is the number of count entries which is computed as
|
|
|
|
textsize / HISTFRACTION
|
|
|
|
`CG' in the above table is the number of call graph arcs. Normally,
|
|
the table is sparse and the profiling code writes out only the those
|
|
entries which are really used in the program run. But since we must
|
|
not extend this table (the profiling file) we'll keep them all here.
|
|
So CN can be executed in advance as
|
|
|
|
MINARCS <= textsize*(ARCDENSITY/100) <= MAXARCS
|
|
|
|
Now the remaining question is: how to build the data structures we can
|
|
work with from this data. We need the from set and must associate the
|
|
froms with all the associated tos. We will do this by constructing this
|
|
data structures at the program start. To do this we'll simply visit all
|
|
entries in the call graph table and add it to the appropriate list. */
|
|
|
|
extern int __profile_frequency (void);
|
|
|
|
/* We define a special type to address the elements of the arc table.
|
|
This is basically the `gmon_cg_arc_record' format but it includes
|
|
the room for the tag and it uses real types. */
|
|
struct here_cg_arc_record
|
|
{
|
|
uintptr_t from_pc;
|
|
uintptr_t self_pc;
|
|
uint32_t count;
|
|
} __attribute__ ((packed));
|
|
|
|
static struct here_cg_arc_record *data;
|
|
|
|
/* This is the number of entry which have been incorporated in the toset. */
|
|
static uint32_t narcs;
|
|
/* This is a pointer to the object representing the number of entries
|
|
currently in the mmaped file. At no point of time this has to be the
|
|
same as NARCS. If it is equal all entries from the file are in our
|
|
lists. */
|
|
static volatile uint32_t *narcsp;
|
|
|
|
/* Description of the currently profiled object. */
|
|
static long int state = GMON_PROF_OFF;
|
|
|
|
static volatile uint16_t *kcount;
|
|
static size_t kcountsize;
|
|
|
|
struct here_fromstruct
|
|
{
|
|
struct here_cg_arc_record volatile *here;
|
|
uint16_t link;
|
|
};
|
|
|
|
static volatile uint16_t *tos;
|
|
|
|
static struct here_fromstruct *froms;
|
|
static uint32_t fromlimit;
|
|
static volatile uint32_t fromidx;
|
|
|
|
static uintptr_t lowpc;
|
|
static size_t textsize;
|
|
static unsigned int hashfraction;
|
|
static unsigned int log_hashfraction;
|
|
|
|
|
|
|
|
/* Set up profiling data to profile object desribed by MAP. The output
|
|
file is found (or created) in OUTPUT_DIR. */
|
|
void
|
|
internal_function
|
|
_dl_start_profile (struct link_map *map, const char *output_dir)
|
|
{
|
|
char *filename;
|
|
int fd;
|
|
struct stat64 st;
|
|
const ElfW(Phdr) *ph;
|
|
ElfW(Addr) mapstart = ~((ElfW(Addr)) 0);
|
|
ElfW(Addr) mapend = 0;
|
|
struct gmon_hdr gmon_hdr;
|
|
struct gmon_hist_hdr hist_hdr;
|
|
char *hist, *cp;
|
|
size_t idx;
|
|
size_t tossize;
|
|
size_t fromssize;
|
|
uintptr_t highpc;
|
|
struct gmon_hdr *addr = NULL;
|
|
off_t expected_size;
|
|
/* See profil(2) where this is described. */
|
|
int s_scale;
|
|
#define SCALE_1_TO_1 0x10000L
|
|
|
|
/* Compute the size of the sections which contain program code. */
|
|
for (ph = map->l_phdr; ph < &map->l_phdr[map->l_phnum]; ++ph)
|
|
if (ph->p_type == PT_LOAD && (ph->p_flags & PF_X))
|
|
{
|
|
ElfW(Addr) start = (ph->p_vaddr & ~(_dl_pagesize - 1));
|
|
ElfW(Addr) end = ((ph->p_vaddr + ph->p_memsz + _dl_pagesize - 1)
|
|
& ~(_dl_pagesize - 1));
|
|
|
|
if (start < mapstart)
|
|
mapstart = start;
|
|
if (end > mapend)
|
|
mapend = end;
|
|
}
|
|
|
|
/* Now we can compute the size of the profiling data. This is done
|
|
with the same formulars as in `monstartup' (see gmon.c). */
|
|
state = GMON_PROF_OFF;
|
|
lowpc = ROUNDDOWN (mapstart + map->l_addr,
|
|
HISTFRACTION * sizeof (HISTCOUNTER));
|
|
highpc = ROUNDUP (mapend + map->l_addr,
|
|
HISTFRACTION * sizeof (HISTCOUNTER));
|
|
textsize = highpc - lowpc;
|
|
kcountsize = textsize / HISTFRACTION;
|
|
hashfraction = HASHFRACTION;
|
|
if ((HASHFRACTION & (HASHFRACTION - 1)) == 0)
|
|
/* If HASHFRACTION is a power of two, mcount can use shifting
|
|
instead of integer division. Precompute shift amount. */
|
|
log_hashfraction = __ffs (hashfraction * sizeof (*froms)) - 1;
|
|
else
|
|
log_hashfraction = -1;
|
|
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 + fromssize * sizeof (struct here_cg_arc_record));
|
|
|
|
/* Create the gmon_hdr we expect or write. */
|
|
memset (&gmon_hdr, '\0', sizeof (struct gmon_hdr));
|
|
memcpy (&gmon_hdr.cookie[0], GMON_MAGIC, sizeof (gmon_hdr.cookie));
|
|
*(int32_t *) gmon_hdr.version = GMON_SHOBJ_VERSION;
|
|
|
|
/* Create the hist_hdr we expect or write. */
|
|
*(char **) hist_hdr.low_pc = (char *) mapstart;
|
|
*(char **) hist_hdr.high_pc = (char *) mapend;
|
|
*(int32_t *) hist_hdr.hist_size = kcountsize / sizeof (HISTCOUNTER);
|
|
*(int32_t *) hist_hdr.prof_rate = __profile_frequency ();
|
|
strncpy (hist_hdr.dimen, "seconds", sizeof (hist_hdr.dimen));
|
|
hist_hdr.dimen_abbrev = 's';
|
|
|
|
/* First determine the output name. We write in the directory
|
|
OUTPUT_DIR and the name is composed from the shared objects
|
|
soname (or the file name) and the ending ".profile". */
|
|
filename = (char *) alloca (strlen (output_dir) + 1 + strlen (_dl_profile)
|
|
+ sizeof ".profile");
|
|
cp = __stpcpy (filename, output_dir);
|
|
*cp++ = '/';
|
|
__stpcpy (__stpcpy (cp, _dl_profile), ".profile");
|
|
|
|
fd = __open (filename, O_RDWR | O_CREAT, 0666);
|
|
if (fd == -1)
|
|
{
|
|
/* We cannot write the profiling data so don't do anything. */
|
|
char buf[400];
|
|
_dl_sysdep_message (filename, ": cannot open file: ",
|
|
__strerror_r (errno, buf, sizeof buf),
|
|
"\n", NULL);
|
|
return;
|
|
}
|
|
|
|
if (__fxstat64 (_STAT_VER, fd, &st) < 0 || !S_ISREG (st.st_mode))
|
|
{
|
|
/* Not stat'able or not a regular file => don't use it. */
|
|
char buf[400];
|
|
int errnum = errno;
|
|
__close (fd);
|
|
_dl_sysdep_message (filename, ": cannot stat file: ",
|
|
__strerror_r (errnum, buf, sizeof buf),
|
|
"\n", NULL);
|
|
return;
|
|
}
|
|
|
|
/* Test the size. If it does not match what we expect from the size
|
|
values in the map MAP we don't use it and warn the user. */
|
|
if (st.st_size == 0)
|
|
{
|
|
/* We have to create the file. */
|
|
char buf[_dl_pagesize];
|
|
|
|
memset (buf, '\0', _dl_pagesize);
|
|
|
|
if (__lseek (fd, expected_size & ~(_dl_pagesize - 1), SEEK_SET) == -1)
|
|
{
|
|
char buf[400];
|
|
int errnum;
|
|
cannot_create:
|
|
errnum = errno;
|
|
__close (fd);
|
|
_dl_sysdep_message (filename, ": cannot create file: ",
|
|
__strerror_r (errnum, buf, sizeof buf),
|
|
"\n", NULL);
|
|
return;
|
|
}
|
|
|
|
if (TEMP_FAILURE_RETRY (__libc_write (fd, buf, (expected_size
|
|
& (_dl_pagesize - 1))))
|
|
< 0)
|
|
goto cannot_create;
|
|
}
|
|
else if (st.st_size != expected_size)
|
|
{
|
|
__close (fd);
|
|
wrong_format:
|
|
|
|
if (addr != NULL)
|
|
__munmap ((void *) addr, expected_size);
|
|
|
|
_dl_sysdep_message (filename,
|
|
": file is no correct profile data file for `",
|
|
_dl_profile, "'\n", NULL);
|
|
return;
|
|
}
|
|
|
|
addr = (struct gmon_hdr *) __mmap (NULL, expected_size, PROT_READ|PROT_WRITE,
|
|
MAP_SHARED|MAP_FILE, fd, 0);
|
|
if (addr == (struct gmon_hdr *) MAP_FAILED)
|
|
{
|
|
char buf[400];
|
|
int errnum = errno;
|
|
__close (fd);
|
|
_dl_sysdep_message (filename, ": cannot map file: ",
|
|
__strerror_r (errnum, buf, sizeof buf),
|
|
"\n", NULL);
|
|
return;
|
|
}
|
|
|
|
/* We don't need the file desriptor anymore. */
|
|
__close (fd);
|
|
|
|
/* Pointer to data after the header. */
|
|
hist = (char *) (addr + 1);
|
|
kcount = (uint16_t *) ((char *) hist + sizeof (uint32_t)
|
|
+ sizeof (struct gmon_hist_hdr));
|
|
|
|
/* Compute pointer to array of the arc information. */
|
|
narcsp = (uint32_t *) ((char *) kcount + kcountsize + sizeof (uint32_t));
|
|
data = (struct here_cg_arc_record *) ((char *) narcsp + sizeof (uint32_t));
|
|
|
|
if (st.st_size == 0)
|
|
{
|
|
/* Create the signature. */
|
|
memcpy (addr, &gmon_hdr, sizeof (struct gmon_hdr));
|
|
|
|
*(uint32_t *) hist = GMON_TAG_TIME_HIST;
|
|
memcpy (hist + sizeof (uint32_t), &hist_hdr,
|
|
sizeof (struct gmon_hist_hdr));
|
|
|
|
narcsp[-1] = GMON_TAG_CG_ARC;
|
|
}
|
|
else
|
|
{
|
|
/* Test the signature in the file. */
|
|
if (memcmp (addr, &gmon_hdr, sizeof (struct gmon_hdr)) != 0
|
|
|| *(uint32_t *) hist != GMON_TAG_TIME_HIST
|
|
|| memcmp (hist + sizeof (uint32_t), &hist_hdr,
|
|
sizeof (struct gmon_hist_hdr)) != 0
|
|
|| narcsp[-1] != GMON_TAG_CG_ARC)
|
|
goto wrong_format;
|
|
}
|
|
|
|
/* Allocate memory for the froms data and the pointer to the tos records. */
|
|
tos = (uint16_t *) calloc (tossize + fromssize, 1);
|
|
if (tos == NULL)
|
|
{
|
|
__munmap ((void *) addr, expected_size);
|
|
_dl_sysdep_fatal ("Out of memory while initializing profiler\n", NULL);
|
|
/* NOTREACHED */
|
|
}
|
|
|
|
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
|
|
we enter a new entry in to toset we will check that everything is
|
|
available in TOS. This happens in _dl_mcount.
|
|
|
|
Loading the entries in reverse order should help to get the most
|
|
frequently used entries at the front of the list. */
|
|
for (idx = narcs = MIN (*narcsp, fromlimit); idx > 0; )
|
|
{
|
|
size_t to_index;
|
|
size_t newfromidx;
|
|
--idx;
|
|
to_index = (data[idx].self_pc / (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)
|
|
{
|
|
#if 0
|
|
s_scale = ((double) kcountsize / (highpc - lowpc)) * SCALE_1_TO_1;
|
|
#else
|
|
size_t range = highpc - lowpc;
|
|
size_t quot = range / kcountsize;
|
|
|
|
if (quot >= SCALE_1_TO_1)
|
|
s_scale = 1;
|
|
else if (quot >= SCALE_1_TO_1 / 256)
|
|
s_scale = SCALE_1_TO_1 / quot;
|
|
else if (range > ULONG_MAX / 256)
|
|
s_scale = (SCALE_1_TO_1 * 256) / (range / (kcountsize / 256));
|
|
else
|
|
s_scale = (SCALE_1_TO_1 * 256) / ((range * 256) / kcountsize);
|
|
#endif
|
|
}
|
|
else
|
|
s_scale = SCALE_1_TO_1;
|
|
|
|
/* Start the profiler. */
|
|
__profil ((void *) kcount, kcountsize, lowpc, s_scale);
|
|
|
|
/* Turn on profiling. */
|
|
state = GMON_PROF_ON;
|
|
}
|
|
|
|
|
|
void
|
|
_dl_mcount (ElfW(Addr) frompc, ElfW(Addr) selfpc)
|
|
{
|
|
volatile uint16_t *topcindex;
|
|
size_t i, fromindex;
|
|
struct here_fromstruct *fromp;
|
|
|
|
#if 0
|
|
/* XXX I think this is now not necessary anymore. */
|
|
if (! compare_and_swap (&state, GMON_PROF_ON, GMON_PROF_BUSY))
|
|
return;
|
|
#endif
|
|
|
|
/* Compute relative addresses. The shared object can be loaded at
|
|
any address. The value of frompc could be anything. We cannot
|
|
restrict it in any way, just set to a fixed value (0) in case it
|
|
is outside the allowed range. These calls show up as calls from
|
|
<external> in the gprof output. */
|
|
frompc -= lowpc;
|
|
if (frompc >= textsize)
|
|
frompc = 0;
|
|
selfpc -= lowpc;
|
|
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->here->from_pc != frompc)
|
|
{
|
|
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 && narcs < fromlimit)
|
|
{
|
|
size_t to_index;
|
|
size_t newfromidx;
|
|
to_index = (data[narcs].self_pc
|
|
/ (hashfraction * sizeof (*tos)));
|
|
newfromidx = exchange_and_add (&fromidx, 1) + 1;
|
|
froms[newfromidx].here = &data[narcs];
|
|
froms[newfromidx].link = tos[to_index];
|
|
tos[to_index] = newfromidx;
|
|
atomic_add (&narcs, 1);
|
|
}
|
|
|
|
/* If we still have no entry stop searching and insert. */
|
|
if (*topcindex == 0)
|
|
{
|
|
uint_fast32_t newarc = 1 + exchange_and_add (narcsp, 1);
|
|
|
|
/* In rare cases it could happen that all entries in FROMS are
|
|
occupied. So we cannot count this anymore. */
|
|
if (newarc >= fromlimit)
|
|
goto done;
|
|
|
|
*topcindex = exchange_and_add (&fromidx, 1) + 1;
|
|
fromp = &froms[*topcindex];
|
|
|
|
fromp->here = &data[newarc];
|
|
data[newarc].from_pc = frompc;
|
|
data[newarc].self_pc = selfpc;
|
|
data[newarc].count = 0;
|
|
fromp->link = 0;
|
|
atomic_add (&narcs, 1);
|
|
|
|
break;
|
|
}
|
|
|
|
fromp = &froms[*topcindex];
|
|
}
|
|
else
|
|
/* Found in. */
|
|
break;
|
|
}
|
|
|
|
/* Increment the counter. */
|
|
atomic_add (&fromp->here->count, 1);
|
|
|
|
done:
|
|
#if 0
|
|
/* XXX See above, Shouldn't be necessary anymore. */
|
|
state = GMON_PROF_ON;
|
|
#endif
|
|
}
|
|
|