linux/tools/perf/util/event.c
Don Zickus bfd66cc71a perf tools: Fix synthesizing mmaps for threads
Currently if a process creates a bunch of threads using pthread_create
and then perf is run in system_wide mode, the mmaps for those threads
are not captured with a synthesized mmap event.

The reason is those threads are not visible when walking the /proc/
directory looking for /proc/<pid>/maps files.  Instead they are
discovered using the /proc/<pid>/tasks file (which the synthesized comm
event uses).

This causes problems when a program is trying to map a data address to a
tid.  Because the tid has no maps, the event is dropped.  Changing the
program to look up using the pid instead of the tid, finds the correct
maps but creates ugly hacks in the program to carry the correct tid
around.

Fix this by moving the walking of the /proc/<pid>/tasks up a level (out
of the comm function) based on Arnaldo's suggestion.

Tweaked things a bit to special case the 'full' bit and 'guest' check.

Signed-off-by: Don Zickus <dzickus@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1393429527-167840-2-git-send-email-dzickus@redhat.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2014-03-14 11:20:44 -03:00

801 lines
20 KiB
C

#include <linux/types.h>
#include "event.h"
#include "debug.h"
#include "machine.h"
#include "sort.h"
#include "string.h"
#include "strlist.h"
#include "thread.h"
#include "thread_map.h"
#include "symbol/kallsyms.h"
static const char *perf_event__names[] = {
[0] = "TOTAL",
[PERF_RECORD_MMAP] = "MMAP",
[PERF_RECORD_MMAP2] = "MMAP2",
[PERF_RECORD_LOST] = "LOST",
[PERF_RECORD_COMM] = "COMM",
[PERF_RECORD_EXIT] = "EXIT",
[PERF_RECORD_THROTTLE] = "THROTTLE",
[PERF_RECORD_UNTHROTTLE] = "UNTHROTTLE",
[PERF_RECORD_FORK] = "FORK",
[PERF_RECORD_READ] = "READ",
[PERF_RECORD_SAMPLE] = "SAMPLE",
[PERF_RECORD_HEADER_ATTR] = "ATTR",
[PERF_RECORD_HEADER_EVENT_TYPE] = "EVENT_TYPE",
[PERF_RECORD_HEADER_TRACING_DATA] = "TRACING_DATA",
[PERF_RECORD_HEADER_BUILD_ID] = "BUILD_ID",
[PERF_RECORD_FINISHED_ROUND] = "FINISHED_ROUND",
};
const char *perf_event__name(unsigned int id)
{
if (id >= ARRAY_SIZE(perf_event__names))
return "INVALID";
if (!perf_event__names[id])
return "UNKNOWN";
return perf_event__names[id];
}
static struct perf_sample synth_sample = {
.pid = -1,
.tid = -1,
.time = -1,
.stream_id = -1,
.cpu = -1,
.period = 1,
};
static pid_t perf_event__get_comm_tgid(pid_t pid, char *comm, size_t len)
{
char filename[PATH_MAX];
char bf[BUFSIZ];
FILE *fp;
size_t size = 0;
pid_t tgid = -1;
snprintf(filename, sizeof(filename), "/proc/%d/status", pid);
fp = fopen(filename, "r");
if (fp == NULL) {
pr_debug("couldn't open %s\n", filename);
return 0;
}
while (!comm[0] || (tgid < 0)) {
if (fgets(bf, sizeof(bf), fp) == NULL) {
pr_warning("couldn't get COMM and pgid, malformed %s\n",
filename);
break;
}
if (memcmp(bf, "Name:", 5) == 0) {
char *name = bf + 5;
while (*name && isspace(*name))
++name;
size = strlen(name) - 1;
if (size >= len)
size = len - 1;
memcpy(comm, name, size);
comm[size] = '\0';
} else if (memcmp(bf, "Tgid:", 5) == 0) {
char *tgids = bf + 5;
while (*tgids && isspace(*tgids))
++tgids;
tgid = atoi(tgids);
}
}
fclose(fp);
return tgid;
}
static pid_t perf_event__synthesize_comm(struct perf_tool *tool,
union perf_event *event, pid_t pid,
perf_event__handler_t process,
struct machine *machine)
{
size_t size;
pid_t tgid;
memset(&event->comm, 0, sizeof(event->comm));
if (machine__is_host(machine))
tgid = perf_event__get_comm_tgid(pid, event->comm.comm,
sizeof(event->comm.comm));
else
tgid = machine->pid;
if (tgid < 0)
goto out;
event->comm.pid = tgid;
event->comm.header.type = PERF_RECORD_COMM;
size = strlen(event->comm.comm) + 1;
size = PERF_ALIGN(size, sizeof(u64));
memset(event->comm.comm + size, 0, machine->id_hdr_size);
event->comm.header.size = (sizeof(event->comm) -
(sizeof(event->comm.comm) - size) +
machine->id_hdr_size);
event->comm.tid = pid;
if (process(tool, event, &synth_sample, machine) != 0)
return -1;
out:
return tgid;
}
int perf_event__synthesize_mmap_events(struct perf_tool *tool,
union perf_event *event,
pid_t pid, pid_t tgid,
perf_event__handler_t process,
struct machine *machine,
bool mmap_data)
{
char filename[PATH_MAX];
FILE *fp;
int rc = 0;
if (machine__is_default_guest(machine))
return 0;
snprintf(filename, sizeof(filename), "%s/proc/%d/maps",
machine->root_dir, pid);
fp = fopen(filename, "r");
if (fp == NULL) {
/*
* We raced with a task exiting - just return:
*/
pr_debug("couldn't open %s\n", filename);
return -1;
}
event->header.type = PERF_RECORD_MMAP;
while (1) {
char bf[BUFSIZ];
char prot[5];
char execname[PATH_MAX];
char anonstr[] = "//anon";
size_t size;
ssize_t n;
if (fgets(bf, sizeof(bf), fp) == NULL)
break;
/* ensure null termination since stack will be reused. */
strcpy(execname, "");
/* 00400000-0040c000 r-xp 00000000 fd:01 41038 /bin/cat */
n = sscanf(bf, "%"PRIx64"-%"PRIx64" %s %"PRIx64" %*x:%*x %*u %s\n",
&event->mmap.start, &event->mmap.len, prot,
&event->mmap.pgoff,
execname);
/*
* Anon maps don't have the execname.
*/
if (n < 4)
continue;
/*
* Just like the kernel, see __perf_event_mmap in kernel/perf_event.c
*/
if (machine__is_host(machine))
event->header.misc = PERF_RECORD_MISC_USER;
else
event->header.misc = PERF_RECORD_MISC_GUEST_USER;
if (prot[2] != 'x') {
if (!mmap_data || prot[0] != 'r')
continue;
event->header.misc |= PERF_RECORD_MISC_MMAP_DATA;
}
if (!strcmp(execname, ""))
strcpy(execname, anonstr);
size = strlen(execname) + 1;
memcpy(event->mmap.filename, execname, size);
size = PERF_ALIGN(size, sizeof(u64));
event->mmap.len -= event->mmap.start;
event->mmap.header.size = (sizeof(event->mmap) -
(sizeof(event->mmap.filename) - size));
memset(event->mmap.filename + size, 0, machine->id_hdr_size);
event->mmap.header.size += machine->id_hdr_size;
event->mmap.pid = tgid;
event->mmap.tid = pid;
if (process(tool, event, &synth_sample, machine) != 0) {
rc = -1;
break;
}
}
fclose(fp);
return rc;
}
int perf_event__synthesize_modules(struct perf_tool *tool,
perf_event__handler_t process,
struct machine *machine)
{
int rc = 0;
struct rb_node *nd;
struct map_groups *kmaps = &machine->kmaps;
union perf_event *event = zalloc((sizeof(event->mmap) +
machine->id_hdr_size));
if (event == NULL) {
pr_debug("Not enough memory synthesizing mmap event "
"for kernel modules\n");
return -1;
}
event->header.type = PERF_RECORD_MMAP;
/*
* kernel uses 0 for user space maps, see kernel/perf_event.c
* __perf_event_mmap
*/
if (machine__is_host(machine))
event->header.misc = PERF_RECORD_MISC_KERNEL;
else
event->header.misc = PERF_RECORD_MISC_GUEST_KERNEL;
for (nd = rb_first(&kmaps->maps[MAP__FUNCTION]);
nd; nd = rb_next(nd)) {
size_t size;
struct map *pos = rb_entry(nd, struct map, rb_node);
if (pos->dso->kernel)
continue;
size = PERF_ALIGN(pos->dso->long_name_len + 1, sizeof(u64));
event->mmap.header.type = PERF_RECORD_MMAP;
event->mmap.header.size = (sizeof(event->mmap) -
(sizeof(event->mmap.filename) - size));
memset(event->mmap.filename + size, 0, machine->id_hdr_size);
event->mmap.header.size += machine->id_hdr_size;
event->mmap.start = pos->start;
event->mmap.len = pos->end - pos->start;
event->mmap.pid = machine->pid;
memcpy(event->mmap.filename, pos->dso->long_name,
pos->dso->long_name_len + 1);
if (process(tool, event, &synth_sample, machine) != 0) {
rc = -1;
break;
}
}
free(event);
return rc;
}
static int __event__synthesize_thread(union perf_event *comm_event,
union perf_event *mmap_event,
pid_t pid, int full,
perf_event__handler_t process,
struct perf_tool *tool,
struct machine *machine, bool mmap_data)
{
char filename[PATH_MAX];
DIR *tasks;
struct dirent dirent, *next;
pid_t tgid;
/* special case: only send one comm event using passed in pid */
if (!full) {
tgid = perf_event__synthesize_comm(tool, comm_event, pid,
process, machine);
if (tgid == -1)
return -1;
return perf_event__synthesize_mmap_events(tool, mmap_event, pid, tgid,
process, machine, mmap_data);
}
if (machine__is_default_guest(machine))
return 0;
snprintf(filename, sizeof(filename), "%s/proc/%d/task",
machine->root_dir, pid);
tasks = opendir(filename);
if (tasks == NULL) {
pr_debug("couldn't open %s\n", filename);
return 0;
}
while (!readdir_r(tasks, &dirent, &next) && next) {
char *end;
int rc = 0;
pid_t _pid;
_pid = strtol(dirent.d_name, &end, 10);
if (*end)
continue;
tgid = perf_event__synthesize_comm(tool, comm_event, _pid,
process, machine);
if (tgid == -1)
return -1;
/* process the thread's maps too */
rc = perf_event__synthesize_mmap_events(tool, mmap_event, _pid, tgid,
process, machine, mmap_data);
if (rc)
return rc;
}
closedir(tasks);
return 0;
}
int perf_event__synthesize_thread_map(struct perf_tool *tool,
struct thread_map *threads,
perf_event__handler_t process,
struct machine *machine,
bool mmap_data)
{
union perf_event *comm_event, *mmap_event;
int err = -1, thread, j;
comm_event = malloc(sizeof(comm_event->comm) + machine->id_hdr_size);
if (comm_event == NULL)
goto out;
mmap_event = malloc(sizeof(mmap_event->mmap) + machine->id_hdr_size);
if (mmap_event == NULL)
goto out_free_comm;
err = 0;
for (thread = 0; thread < threads->nr; ++thread) {
if (__event__synthesize_thread(comm_event, mmap_event,
threads->map[thread], 0,
process, tool, machine,
mmap_data)) {
err = -1;
break;
}
/*
* comm.pid is set to thread group id by
* perf_event__synthesize_comm
*/
if ((int) comm_event->comm.pid != threads->map[thread]) {
bool need_leader = true;
/* is thread group leader in thread_map? */
for (j = 0; j < threads->nr; ++j) {
if ((int) comm_event->comm.pid == threads->map[j]) {
need_leader = false;
break;
}
}
/* if not, generate events for it */
if (need_leader &&
__event__synthesize_thread(comm_event, mmap_event,
comm_event->comm.pid, 0,
process, tool, machine,
mmap_data)) {
err = -1;
break;
}
}
}
free(mmap_event);
out_free_comm:
free(comm_event);
out:
return err;
}
int perf_event__synthesize_threads(struct perf_tool *tool,
perf_event__handler_t process,
struct machine *machine, bool mmap_data)
{
DIR *proc;
char proc_path[PATH_MAX];
struct dirent dirent, *next;
union perf_event *comm_event, *mmap_event;
int err = -1;
comm_event = malloc(sizeof(comm_event->comm) + machine->id_hdr_size);
if (comm_event == NULL)
goto out;
mmap_event = malloc(sizeof(mmap_event->mmap) + machine->id_hdr_size);
if (mmap_event == NULL)
goto out_free_comm;
if (machine__is_default_guest(machine))
return 0;
snprintf(proc_path, sizeof(proc_path), "%s/proc", machine->root_dir);
proc = opendir(proc_path);
if (proc == NULL)
goto out_free_mmap;
while (!readdir_r(proc, &dirent, &next) && next) {
char *end;
pid_t pid = strtol(dirent.d_name, &end, 10);
if (*end) /* only interested in proper numerical dirents */
continue;
/*
* We may race with exiting thread, so don't stop just because
* one thread couldn't be synthesized.
*/
__event__synthesize_thread(comm_event, mmap_event, pid, 1,
process, tool, machine, mmap_data);
}
err = 0;
closedir(proc);
out_free_mmap:
free(mmap_event);
out_free_comm:
free(comm_event);
out:
return err;
}
struct process_symbol_args {
const char *name;
u64 start;
};
static int find_symbol_cb(void *arg, const char *name, char type,
u64 start)
{
struct process_symbol_args *args = arg;
/*
* Must be a function or at least an alias, as in PARISC64, where "_text" is
* an 'A' to the same address as "_stext".
*/
if (!(symbol_type__is_a(type, MAP__FUNCTION) ||
type == 'A') || strcmp(name, args->name))
return 0;
args->start = start;
return 1;
}
u64 kallsyms__get_function_start(const char *kallsyms_filename,
const char *symbol_name)
{
struct process_symbol_args args = { .name = symbol_name, };
if (kallsyms__parse(kallsyms_filename, &args, find_symbol_cb) <= 0)
return 0;
return args.start;
}
int perf_event__synthesize_kernel_mmap(struct perf_tool *tool,
perf_event__handler_t process,
struct machine *machine)
{
size_t size;
const char *mmap_name;
char name_buff[PATH_MAX];
struct map *map;
struct kmap *kmap;
int err;
/*
* We should get this from /sys/kernel/sections/.text, but till that is
* available use this, and after it is use this as a fallback for older
* kernels.
*/
union perf_event *event = zalloc((sizeof(event->mmap) +
machine->id_hdr_size));
if (event == NULL) {
pr_debug("Not enough memory synthesizing mmap event "
"for kernel modules\n");
return -1;
}
mmap_name = machine__mmap_name(machine, name_buff, sizeof(name_buff));
if (machine__is_host(machine)) {
/*
* kernel uses PERF_RECORD_MISC_USER for user space maps,
* see kernel/perf_event.c __perf_event_mmap
*/
event->header.misc = PERF_RECORD_MISC_KERNEL;
} else {
event->header.misc = PERF_RECORD_MISC_GUEST_KERNEL;
}
map = machine->vmlinux_maps[MAP__FUNCTION];
kmap = map__kmap(map);
size = snprintf(event->mmap.filename, sizeof(event->mmap.filename),
"%s%s", mmap_name, kmap->ref_reloc_sym->name) + 1;
size = PERF_ALIGN(size, sizeof(u64));
event->mmap.header.type = PERF_RECORD_MMAP;
event->mmap.header.size = (sizeof(event->mmap) -
(sizeof(event->mmap.filename) - size) + machine->id_hdr_size);
event->mmap.pgoff = kmap->ref_reloc_sym->addr;
event->mmap.start = map->start;
event->mmap.len = map->end - event->mmap.start;
event->mmap.pid = machine->pid;
err = process(tool, event, &synth_sample, machine);
free(event);
return err;
}
size_t perf_event__fprintf_comm(union perf_event *event, FILE *fp)
{
return fprintf(fp, ": %s:%d\n", event->comm.comm, event->comm.tid);
}
int perf_event__process_comm(struct perf_tool *tool __maybe_unused,
union perf_event *event,
struct perf_sample *sample,
struct machine *machine)
{
return machine__process_comm_event(machine, event, sample);
}
int perf_event__process_lost(struct perf_tool *tool __maybe_unused,
union perf_event *event,
struct perf_sample *sample,
struct machine *machine)
{
return machine__process_lost_event(machine, event, sample);
}
size_t perf_event__fprintf_mmap(union perf_event *event, FILE *fp)
{
return fprintf(fp, " %d/%d: [%#" PRIx64 "(%#" PRIx64 ") @ %#" PRIx64 "]: %c %s\n",
event->mmap.pid, event->mmap.tid, event->mmap.start,
event->mmap.len, event->mmap.pgoff,
(event->header.misc & PERF_RECORD_MISC_MMAP_DATA) ? 'r' : 'x',
event->mmap.filename);
}
size_t perf_event__fprintf_mmap2(union perf_event *event, FILE *fp)
{
return fprintf(fp, " %d/%d: [%#" PRIx64 "(%#" PRIx64 ") @ %#" PRIx64
" %02x:%02x %"PRIu64" %"PRIu64"]: %c %s\n",
event->mmap2.pid, event->mmap2.tid, event->mmap2.start,
event->mmap2.len, event->mmap2.pgoff, event->mmap2.maj,
event->mmap2.min, event->mmap2.ino,
event->mmap2.ino_generation,
(event->header.misc & PERF_RECORD_MISC_MMAP_DATA) ? 'r' : 'x',
event->mmap2.filename);
}
int perf_event__process_mmap(struct perf_tool *tool __maybe_unused,
union perf_event *event,
struct perf_sample *sample,
struct machine *machine)
{
return machine__process_mmap_event(machine, event, sample);
}
int perf_event__process_mmap2(struct perf_tool *tool __maybe_unused,
union perf_event *event,
struct perf_sample *sample,
struct machine *machine)
{
return machine__process_mmap2_event(machine, event, sample);
}
size_t perf_event__fprintf_task(union perf_event *event, FILE *fp)
{
return fprintf(fp, "(%d:%d):(%d:%d)\n",
event->fork.pid, event->fork.tid,
event->fork.ppid, event->fork.ptid);
}
int perf_event__process_fork(struct perf_tool *tool __maybe_unused,
union perf_event *event,
struct perf_sample *sample,
struct machine *machine)
{
return machine__process_fork_event(machine, event, sample);
}
int perf_event__process_exit(struct perf_tool *tool __maybe_unused,
union perf_event *event,
struct perf_sample *sample,
struct machine *machine)
{
return machine__process_exit_event(machine, event, sample);
}
size_t perf_event__fprintf(union perf_event *event, FILE *fp)
{
size_t ret = fprintf(fp, "PERF_RECORD_%s",
perf_event__name(event->header.type));
switch (event->header.type) {
case PERF_RECORD_COMM:
ret += perf_event__fprintf_comm(event, fp);
break;
case PERF_RECORD_FORK:
case PERF_RECORD_EXIT:
ret += perf_event__fprintf_task(event, fp);
break;
case PERF_RECORD_MMAP:
ret += perf_event__fprintf_mmap(event, fp);
break;
case PERF_RECORD_MMAP2:
ret += perf_event__fprintf_mmap2(event, fp);
break;
default:
ret += fprintf(fp, "\n");
}
return ret;
}
int perf_event__process(struct perf_tool *tool __maybe_unused,
union perf_event *event,
struct perf_sample *sample,
struct machine *machine)
{
return machine__process_event(machine, event, sample);
}
void thread__find_addr_map(struct thread *thread,
struct machine *machine, u8 cpumode,
enum map_type type, u64 addr,
struct addr_location *al)
{
struct map_groups *mg = &thread->mg;
bool load_map = false;
al->machine = machine;
al->thread = thread;
al->addr = addr;
al->cpumode = cpumode;
al->filtered = false;
if (machine == NULL) {
al->map = NULL;
return;
}
if (cpumode == PERF_RECORD_MISC_KERNEL && perf_host) {
al->level = 'k';
mg = &machine->kmaps;
load_map = true;
} else if (cpumode == PERF_RECORD_MISC_USER && perf_host) {
al->level = '.';
} else if (cpumode == PERF_RECORD_MISC_GUEST_KERNEL && perf_guest) {
al->level = 'g';
mg = &machine->kmaps;
load_map = true;
} else if (cpumode == PERF_RECORD_MISC_GUEST_USER && perf_guest) {
al->level = 'u';
} else {
al->level = 'H';
al->map = NULL;
if ((cpumode == PERF_RECORD_MISC_GUEST_USER ||
cpumode == PERF_RECORD_MISC_GUEST_KERNEL) &&
!perf_guest)
al->filtered = true;
if ((cpumode == PERF_RECORD_MISC_USER ||
cpumode == PERF_RECORD_MISC_KERNEL) &&
!perf_host)
al->filtered = true;
return;
}
try_again:
al->map = map_groups__find(mg, type, al->addr);
if (al->map == NULL) {
/*
* If this is outside of all known maps, and is a negative
* address, try to look it up in the kernel dso, as it might be
* a vsyscall or vdso (which executes in user-mode).
*
* XXX This is nasty, we should have a symbol list in the
* "[vdso]" dso, but for now lets use the old trick of looking
* in the whole kernel symbol list.
*/
if ((long long)al->addr < 0 &&
cpumode == PERF_RECORD_MISC_USER &&
machine && mg != &machine->kmaps) {
mg = &machine->kmaps;
goto try_again;
}
} else {
/*
* Kernel maps might be changed when loading symbols so loading
* must be done prior to using kernel maps.
*/
if (load_map)
map__load(al->map, machine->symbol_filter);
al->addr = al->map->map_ip(al->map, al->addr);
}
}
void thread__find_addr_location(struct thread *thread, struct machine *machine,
u8 cpumode, enum map_type type, u64 addr,
struct addr_location *al)
{
thread__find_addr_map(thread, machine, cpumode, type, addr, al);
if (al->map != NULL)
al->sym = map__find_symbol(al->map, al->addr,
machine->symbol_filter);
else
al->sym = NULL;
}
int perf_event__preprocess_sample(const union perf_event *event,
struct machine *machine,
struct addr_location *al,
struct perf_sample *sample)
{
u8 cpumode = event->header.misc & PERF_RECORD_MISC_CPUMODE_MASK;
struct thread *thread = machine__findnew_thread(machine, sample->pid,
sample->pid);
if (thread == NULL)
return -1;
if (thread__is_filtered(thread))
goto out_filtered;
dump_printf(" ... thread: %s:%d\n", thread__comm_str(thread), thread->tid);
/*
* Have we already created the kernel maps for this machine?
*
* This should have happened earlier, when we processed the kernel MMAP
* events, but for older perf.data files there was no such thing, so do
* it now.
*/
if (cpumode == PERF_RECORD_MISC_KERNEL &&
machine->vmlinux_maps[MAP__FUNCTION] == NULL)
machine__create_kernel_maps(machine);
thread__find_addr_map(thread, machine, cpumode, MAP__FUNCTION,
sample->ip, al);
dump_printf(" ...... dso: %s\n",
al->map ? al->map->dso->long_name :
al->level == 'H' ? "[hypervisor]" : "<not found>");
al->sym = NULL;
al->cpu = sample->cpu;
if (al->map) {
struct dso *dso = al->map->dso;
if (symbol_conf.dso_list &&
(!dso || !(strlist__has_entry(symbol_conf.dso_list,
dso->short_name) ||
(dso->short_name != dso->long_name &&
strlist__has_entry(symbol_conf.dso_list,
dso->long_name)))))
goto out_filtered;
al->sym = map__find_symbol(al->map, al->addr,
machine->symbol_filter);
}
if (symbol_conf.sym_list &&
(!al->sym || !strlist__has_entry(symbol_conf.sym_list,
al->sym->name)))
goto out_filtered;
return 0;
out_filtered:
al->filtered = true;
return 0;
}