Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

libbpf-tools/offcputime: Add multi process/thread support #5111

Open
wants to merge 2 commits into
base: master
Choose a base branch
from
Open

libbpf-tools/offcputime: Add multi process/thread support #5111

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
ffa84f8
libbpf-tools/offcputime: Add multi process/thread support
ekyooo Sep 16, 2024
6478750
libbpf-tools/trace_helpers: Add a utility to split and convert string
ekyooo Sep 26, 2024
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
25 changes: 21 additions & 4 deletions libbpf-tools/offcputime.bpf.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -14,8 +14,8 @@ const volatile bool kernel_threads_only = false;
const volatile bool user_threads_only = false;
const volatile __u64 max_block_ns = -1;
const volatile __u64 min_block_ns = 1;
const volatile pid_t targ_tgid = -1;
const volatile pid_t targ_pid = -1;
const volatile bool filter_by_tgid = false;
const volatile bool filter_by_pid = false;
const volatile long state = -1;

struct internal_key {
Expand All @@ -42,11 +42,28 @@ struct {
__uint(max_entries, MAX_ENTRIES);
} info SEC(".maps");

struct {
__uint(type, BPF_MAP_TYPE_HASH);
__type(key, u32);
__type(value, u8);
__uint(max_entries, MAX_PID_NR);
} tgids SEC(".maps");

struct {
__uint(type, BPF_MAP_TYPE_HASH);
__type(key, u32);
__type(value, u8);
__uint(max_entries, MAX_TID_NR);
} pids SEC(".maps");

static bool allow_record(struct task_struct *t)
{
if (targ_tgid != -1 && targ_tgid != t->tgid)
u32 tgid = t->tgid;
u32 pid = t->pid;

if (filter_by_tgid && !bpf_map_lookup_elem(&tgids, &tgid))
return false;
if (targ_pid != -1 && targ_pid != t->pid)
if (filter_by_pid && !bpf_map_lookup_elem(&pids, &pid))
return false;
if (user_threads_only && t->flags & PF_KTHREAD)
return false;
Expand Down
117 changes: 93 additions & 24 deletions libbpf-tools/offcputime.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -16,8 +16,8 @@
#include "trace_helpers.h"

static struct env {
pid_t pid;
pid_t tid;
pid_t pids[MAX_PID_NR];
pid_t tids[MAX_TID_NR];
bool user_threads_only;
bool kernel_threads_only;
int stack_storage_size;
Expand All @@ -28,8 +28,6 @@ static struct env {
int duration;
bool verbose;
} env = {
.pid = -1,
.tid = -1,
.stack_storage_size = 1024,
.perf_max_stack_depth = 127,
.min_block_time = 1,
Expand All @@ -52,8 +50,8 @@ const char argp_program_doc[] =
" offcputime 5 # trace for 5 seconds only\n"
" offcputime -m 1000 # trace only events that last more than 1000 usec\n"
" offcputime -M 10000 # trace only events that last less than 10000 usec\n"
" offcputime -p 185 # only trace threads for PID 185\n"
" offcputime -t 188 # only trace thread 188\n"
" offcputime -p 185,175,165 # only trace threads for PID 185,175,165\n"
" offcputime -t 188,120,134 # only trace threads 188,120,134\n"
" offcputime -u # only trace user threads (no kernel)\n"
" offcputime -k # only trace kernel threads (no user)\n";

Expand All @@ -62,8 +60,8 @@ const char argp_program_doc[] =
#define OPT_STATE 3 /* --state */

static const struct argp_option opts[] = {
{ "pid", 'p', "PID", 0, "Trace this PID only", 0 },
{ "tid", 't', "TID", 0, "Trace this TID only", 0 },
{ "pid", 'p', "PID", 0, "Trace these PIDs only, comma-separated list", 0 },
{ "tid", 't', "TID", 0, "Trace these TIDs only, comma-separated list", 0 },
{ "user-threads-only", 'u', NULL, 0,
"User threads only (no kernel threads)", 0 },
{ "kernel-threads-only", 'k', NULL, 0,
Expand All @@ -85,6 +83,7 @@ static const struct argp_option opts[] = {
static error_t parse_arg(int key, char *arg, struct argp_state *state)
{
static int pos_args;
int ret;

switch (key) {
case 'h':
Expand All @@ -94,18 +93,28 @@ static error_t parse_arg(int key, char *arg, struct argp_state *state)
env.verbose = true;
break;
case 'p':
errno = 0;
env.pid = strtol(arg, NULL, 10);
if (errno) {
fprintf(stderr, "invalid PID: %s\n", arg);
ret = split_convert(strdup(arg), ",", env.pids, sizeof(env.pids),
sizeof(pid_t), str_to_int);
if (ret) {
if (ret == -ENOBUFS)
fprintf(stderr, "the number of pid is too big, please "
"increase MAX_PID_NR's value and recompile\n");
else
fprintf(stderr, "invalid PID: %s\n", arg);

argp_usage(state);
}
break;
case 't':
errno = 0;
env.tid = strtol(arg, NULL, 10);
if (errno || env.tid <= 0) {
fprintf(stderr, "Invalid TID: %s\n", arg);
ret = split_convert(strdup(arg), ",", env.tids, sizeof(env.tids),
sizeof(pid_t), str_to_int);
if (ret) {
if (ret == -ENOBUFS)
fprintf(stderr, "the number of tid is too big, please "
"increase MAX_TID_NR's value and recompile\n");
else
fprintf(stderr, "invalid TID: %s\n", arg);

argp_usage(state);
}
break;
Expand Down Expand Up @@ -281,6 +290,41 @@ static void print_map(struct ksyms *ksyms, struct syms_cache *syms_cache,
free(ip);
}

static bool print_header_threads()
{
int i;
bool printed = false;

if (env.pids[0]) {
printf(" PID [");
for (i = 0; i < MAX_PID_NR && env.pids[i]; i++)
printf("%d%s", env.pids[i], (i < MAX_PID_NR - 1 && env.pids[i + 1]) ? ", " : "]");
printed = true;
}

if (env.tids[0]) {
printf(" TID [");
for (i = 0; i < MAX_TID_NR && env.tids[i]; i++)
printf("%d%s", env.tids[i], (i < MAX_TID_NR - 1 && env.tids[i + 1]) ? ", " : "]");
printed = true;
}

return printed;
}

static void print_headers()
{
printf("Tracing off-CPU time (us) of");

if (!print_header_threads())
printf(" all threads");

if (env.duration < 99999999)
printf(" for %d secs.\n", env.duration);
else
printf("... Hit Ctrl-C to end.\n");
}

int main(int argc, char **argv)
{
static const struct argp argp = {
Expand All @@ -291,7 +335,9 @@ int main(int argc, char **argv)
struct syms_cache *syms_cache = NULL;
struct ksyms *ksyms = NULL;
struct offcputime_bpf *obj;
int err;
int pids_fd, tids_fd;
int err, i;
__u8 val = 0;

err = argp_parse(&argp, argc, argv, 0, NULL, NULL);
if (err)
Expand All @@ -314,14 +360,18 @@ int main(int argc, char **argv)
}

/* initialize global data (filtering options) */
obj->rodata->targ_tgid = env.pid;
obj->rodata->targ_pid = env.tid;
obj->rodata->user_threads_only = env.user_threads_only;
obj->rodata->kernel_threads_only = env.kernel_threads_only;
obj->rodata->state = env.state;
obj->rodata->min_block_ns = env.min_block_time;
obj->rodata->max_block_ns = env.max_block_time;

/* User space PID and TID correspond to TGID and PID in the kernel, respectively */
if (env.pids[0])
obj->rodata->filter_by_tgid = true;
if (env.tids[0])
obj->rodata->filter_by_pid = true;
Copy link
Collaborator

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Should we do both obj->rodata->filter_by_tgid and obj->rodata->filter_by_pid?

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

it's modified. thank you.


bpf_map__set_value_size(obj->maps.stackmap,
env.perf_max_stack_depth * sizeof(unsigned long));
bpf_map__set_max_entries(obj->maps.stackmap, env.stack_storage_size);
Expand All @@ -331,6 +381,28 @@ int main(int argc, char **argv)
fprintf(stderr, "failed to load BPF programs\n");
goto cleanup;
}

if (env.pids[0]) {
/* User pids_fd points to the tgids map in the BPF program */
pids_fd = bpf_map__fd(obj->maps.tgids);
for (i = 0; i < MAX_PID_NR && env.pids[i]; i++) {
if (bpf_map_update_elem(pids_fd, &(env.pids[i]), &val, BPF_ANY) != 0) {
fprintf(stderr, "failed to init pids map: %s\n", strerror(errno));
goto cleanup;
}
}
}
if (env.tids[0]) {
/* User tids_fd points to the pids map in the BPF program */
tids_fd = bpf_map__fd(obj->maps.pids);
for (i = 0; i < MAX_TID_NR && env.tids[i]; i++) {
if (bpf_map_update_elem(tids_fd, &(env.tids[i]), &val, BPF_ANY) != 0) {
fprintf(stderr, "failed to init tids map: %s\n", strerror(errno));
goto cleanup;
}
}
}

ksyms = ksyms__load();
if (!ksyms) {
fprintf(stderr, "failed to load kallsyms\n");
Expand All @@ -349,11 +421,8 @@ int main(int argc, char **argv)

signal(SIGINT, sig_handler);

printf("Tracing off-CPU time (us)");
if (env.duration < 99999999)
printf(" for %d secs.\n", env.duration);
else
printf("... Hit Ctrl-C to end.\n");
print_headers();

/*
* We'll get sleep interrupted when someone presses Ctrl-C (which will
* be "handled" with noop by sig_handler).
Expand Down
2 changes: 2 additions & 0 deletions libbpf-tools/offcputime.h
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -3,6 +3,8 @@
#define __OFFCPUTIME_H

#define TASK_COMM_LEN 16
#define MAX_PID_NR 30
#define MAX_TID_NR 30

struct key_t {
__u32 pid;
Expand Down
27 changes: 4 additions & 23 deletions libbpf-tools/profile.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -132,27 +132,6 @@ struct syms_cache *syms_cache;
struct syms *syms;
static char syminfo[SYM_INFO_LEN];

static int split_pidstr(char *s, char* sep, int max_split, pid_t *pids)
{
char *pid;
int nr = 0;

errno = 0;
pid = strtok(s, sep);
while (pid) {
if (nr >= max_split)
return -ENOBUFS;

pids[nr++] = strtol(pid, NULL, 10);
if (errno)
return -errno;

pid = strtok(NULL, ",");
}

return 0;
}

static error_t parse_arg(int key, char *arg, struct argp_state *state)
{
static int pos_args;
Expand All @@ -166,7 +145,8 @@ static error_t parse_arg(int key, char *arg, struct argp_state *state)
env.verbose = true;
break;
case 'p':
ret = split_pidstr(strdup(arg), ",", MAX_PID_NR, env.pids);
ret = split_convert(strdup(arg), ",", env.pids, sizeof(env.pids),
sizeof(pid_t), str_to_int);
if (ret) {
if (ret == -ENOBUFS)
fprintf(stderr, "the number of pid is too big, please "
Expand All @@ -178,7 +158,8 @@ static error_t parse_arg(int key, char *arg, struct argp_state *state)
}
break;
case 'L':
ret = split_pidstr(strdup(arg), ",", MAX_TID_NR, env.tids);
ret = split_convert(strdup(arg), ",", env.tids, sizeof(env.tids),
sizeof(pid_t), str_to_int);
if (ret) {
if (ret == -ENOBUFS)
fprintf(stderr, "the number of tid is too big, please "
Expand Down
42 changes: 42 additions & 0 deletions libbpf-tools/trace_helpers.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1247,3 +1247,45 @@ bool probe_ringbuf()
close(map_fd);
return true;
}

int split_convert(char *s, const char* delim, void *elems, size_t elems_size,
size_t elem_size, convert_fn_t convert)
{
char *token;
int ret;
char *pos = (char *)elems;

if (!s || !delim || !elems)
return -EINVAL;

token = strtok(s, delim);
while (token) {
if (pos + elem_size > (char*)elems + elems_size)
return -ENOBUFS;

ret = convert(token, pos);
if (ret)
return -ret;

pos += elem_size;
token = strtok(NULL, delim);
}

return 0;
}

int str_to_int(const char *src, void *dest)
{
errno = 0;
*(int*)dest = strtol(src, NULL, 10);

return errno;
Copy link
Collaborator

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Since str_to_int() and str_to_long() are in trace_helpers.c, we should add 'error = 0;' before strtol(). It is possible that errno is not 0 before strtol() and if strtol() works perfectly, errno won't change and the return value will be non-zero.

Copy link
Contributor Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Yes, it's right. It's fixed. Thank you very much.

}

int str_to_long(const char *src, void *dest)
{
errno = 0;
*(long*)dest = strtol(src, NULL, 10);

return errno;
}
12 changes: 12 additions & 0 deletions libbpf-tools/trace_helpers.h
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -108,4 +108,16 @@ bool module_btf_exists(const char *mod);
bool probe_tp_btf(const char *name);
bool probe_ringbuf();

typedef int (*convert_fn_t)(const char *src, void *dest);
int split_convert(char *s, const char* delim, void *elems, size_t elems_size,
size_t elem_size, convert_fn_t convert);
/*
* Implementations of convert_fn_t.
* This can be replaced with a user-defined callback function.
*/
/* converts a string to an integer */
int str_to_int(const char *src, void *dest);
/* converts a string to a long integer */
int str_to_long(const char *src, void *dest);

#endif /* __TRACE_HELPERS_H */