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Merge branch 'bpf-Add-BPF-support-to-all-perf_event'

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Merge branch 'bpf-Add-BPF-support-to-all-perf_event'

Alexei Starovoitov says:

====================
bpf: Add BPF support to all perf_event

v3->v4: one more tweak to reject unsupported events at map
update time as Peter suggested

v2->v3: more refactoring to address Peter's feedback.
Now all perf_events are attachable and readable

v1->v2: address Peter's feedback. Refactor patch 1 to allow attaching
bpf programs to all event types and reading counters from all of them as well
patch 2 - more tests
patch 3 - address Dave's feedback and document bpf_perf_event_read()
and bpf_perf_event_output() properly
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David S. Miller 2017-06-04 21:58:24 -04:00
commit a11227dcc3
10 changed files with 290 additions and 120 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
include/linux/perf_event.h
View File

@ -896,7 +896,7 @@ perf_event_create_kernel_counter(struct perf_event_attr *attr,
void *context);
extern void perf_pmu_migrate_context(struct pmu *pmu,
int src_cpu, int dst_cpu);
extern u64 perf_event_read_local(struct perf_event *event);
int perf_event_read_local(struct perf_event *event, u64 *value);
extern u64 perf_event_read_value(struct perf_event *event,
u64 *enabled, u64 *running);
@ -1301,7 +1301,10 @@ static inline const struct perf_event_attr *perf_event_attrs(struct perf_event *
{
return ERR_PTR(-EINVAL);
}
static inline u64 perf_event_read_local(struct perf_event *event) { return -EINVAL; }
static inline int perf_event_read_local(struct perf_event *event, u64 *value)
{
return -EINVAL;
}
static inline void perf_event_print_debug(void) { }
static inline int perf_event_task_disable(void) { return -EINVAL; }
static inline int perf_event_task_enable(void) { return -EINVAL; }

11
include/uapi/linux/bpf.h
View File

@ -313,8 +313,11 @@ union bpf_attr {
* @flags: room for future extensions
* Return: 0 on success or negative error
*
* u64 bpf_perf_event_read(&map, index)
* Return: Number events read or error code
* u64 bpf_perf_event_read(map, flags)
* read perf event counter value
* @map: pointer to perf_event_array map
* @flags: index of event in the map or bitmask flags
* Return: value of perf event counter read or error code
*
* int bpf_redirect(ifindex, flags)
* redirect to another netdev
@ -328,11 +331,11 @@ union bpf_attr {
* @skb: pointer to skb
* Return: realm if != 0
*
* int bpf_perf_event_output(ctx, map, index, data, size)
* int bpf_perf_event_output(ctx, map, flags, data, size)
* output perf raw sample
* @ctx: struct pt_regs*
* @map: pointer to perf_event_array map
* @index: index of event in the map
* @flags: index of event in the map or bitmask flags
* @data: data on stack to be output as raw data
* @size: size of data
* Return: 0 on success or negative error

28
kernel/bpf/arraymap.c
View File

@ -452,38 +452,24 @@ static void bpf_event_entry_free_rcu(struct bpf_event_entry *ee)
static void *perf_event_fd_array_get_ptr(struct bpf_map *map,
struct file *map_file, int fd)
{
const struct perf_event_attr *attr;
struct bpf_event_entry *ee;
struct perf_event *event;
struct file *perf_file;
u64 value;
perf_file = perf_event_get(fd);
if (IS_ERR(perf_file))
return perf_file;
ee = ERR_PTR(-EOPNOTSUPP);
event = perf_file->private_data;
ee = ERR_PTR(-EINVAL);
attr = perf_event_attrs(event);
if (IS_ERR(attr) || attr->inherit)
if (perf_event_read_local(event, &value) == -EOPNOTSUPP)
goto err_out;
switch (attr->type) {
case PERF_TYPE_SOFTWARE:
if (attr->config != PERF_COUNT_SW_BPF_OUTPUT)
goto err_out;
/* fall-through */
case PERF_TYPE_RAW:
case PERF_TYPE_HARDWARE:
ee = bpf_event_entry_gen(perf_file, map_file);
if (ee)
return ee;
ee = ERR_PTR(-ENOMEM);
/* fall-through */
default:
break;
}
ee = bpf_event_entry_gen(perf_file, map_file);
if (ee)
return ee;
ee = ERR_PTR(-ENOMEM);
err_out:
fput(perf_file);
return ee;

47
kernel/events/core.c
View File

@ -3636,10 +3636,10 @@ static inline u64 perf_event_count(struct perf_event *event)
* will not be local and we cannot read them atomically
* - must not have a pmu::count method
*/
u64 perf_event_read_local(struct perf_event *event)
int perf_event_read_local(struct perf_event *event, u64 *value)
{
unsigned long flags;
u64 val;
int ret = 0;
/*
* Disabling interrupts avoids all counter scheduling (context
@ -3647,25 +3647,37 @@ u64 perf_event_read_local(struct perf_event *event)
*/
local_irq_save(flags);
/* If this is a per-task event, it must be for current */
WARN_ON_ONCE((event->attach_state & PERF_ATTACH_TASK) &&
event->hw.target != current);
/* If this is a per-CPU event, it must be for this CPU */
WARN_ON_ONCE(!(event->attach_state & PERF_ATTACH_TASK) &&
event->cpu != smp_processor_id());
/*
* It must not be an event with inherit set, we cannot read
* all child counters from atomic context.
*/
WARN_ON_ONCE(event->attr.inherit);
if (event->attr.inherit) {
ret = -EOPNOTSUPP;
goto out;
}
/*
* It must not have a pmu::count method, those are not
* NMI safe.
*/
WARN_ON_ONCE(event->pmu->count);
if (event->pmu->count) {
ret = -EOPNOTSUPP;
goto out;
}
/* If this is a per-task event, it must be for current */
if ((event->attach_state & PERF_ATTACH_TASK) &&
event->hw.target != current) {
ret = -EINVAL;
goto out;
}
/* If this is a per-CPU event, it must be for this CPU */
if (!(event->attach_state & PERF_ATTACH_TASK) &&
event->cpu != smp_processor_id()) {
ret = -EINVAL;
goto out;
}
/*
* If the event is currently on this CPU, its either a per-task event,
@ -3675,10 +3687,11 @@ u64 perf_event_read_local(struct perf_event *event)
if (event->oncpu == smp_processor_id())
event->pmu->read(event);
val = local64_read(&event->count);
*value = local64_read(&event->count);
out:
local_irq_restore(flags);
return val;
return ret;
}
static int perf_event_read(struct perf_event *event, bool group)
@ -8037,12 +8050,8 @@ static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
bool is_kprobe, is_tracepoint;
struct bpf_prog *prog;
if (event->attr.type == PERF_TYPE_HARDWARE ||
event->attr.type == PERF_TYPE_SOFTWARE)
return perf_event_set_bpf_handler(event, prog_fd);
if (event->attr.type != PERF_TYPE_TRACEPOINT)
return -EINVAL;
return perf_event_set_bpf_handler(event, prog_fd);
if (event->tp_event->prog)
return -EEXIST;

22
kernel/trace/bpf_trace.c
View File

@ -234,7 +234,8 @@ BPF_CALL_2(bpf_perf_event_read, struct bpf_map *, map, u64, flags)
unsigned int cpu = smp_processor_id();
u64 index = flags & BPF_F_INDEX_MASK;
struct bpf_event_entry *ee;
struct perf_event *event;
u64 value = 0;
int err;
if (unlikely(flags & ~(BPF_F_INDEX_MASK)))
return -EINVAL;
@ -247,21 +248,14 @@ BPF_CALL_2(bpf_perf_event_read, struct bpf_map *, map, u64, flags)
if (!ee)
return -ENOENT;
event = ee->event;
if (unlikely(event->attr.type != PERF_TYPE_HARDWARE &&
event->attr.type != PERF_TYPE_RAW))
return -EINVAL;
/* make sure event is local and doesn't have pmu::count */
if (unlikely(event->oncpu != cpu || event->pmu->count))
return -EINVAL;
err = perf_event_read_local(ee->event, &value);
/*
* we don't know if the function is run successfully by the
* return value. It can be judged in other places, such as
* eBPF programs.
* this api is ugly since we miss [-22..-2] range of valid
* counter values, but that's uapi
*/
return perf_event_read_local(event);
if (err)
return err;
return value;
}
static const struct bpf_func_proto bpf_perf_event_read_proto = {

3
samples/bpf/bpf_helpers.h
View File

@ -31,7 +31,8 @@ static unsigned long long (*bpf_get_current_uid_gid)(void) =
(void *) BPF_FUNC_get_current_uid_gid;
static int (*bpf_get_current_comm)(void *buf, int buf_size) =
(void *) BPF_FUNC_get_current_comm;
static int (*bpf_perf_event_read)(void *map, int index) =
static unsigned long long (*bpf_perf_event_read)(void *map,
unsigned long long flags) =
(void *) BPF_FUNC_perf_event_read;
static int (*bpf_clone_redirect)(void *ctx, int ifindex, int flags) =
(void *) BPF_FUNC_clone_redirect;

73
samples/bpf/trace_event_user.c
View File

@ -75,7 +75,10 @@ static void print_stack(struct key_t *key, __u64 count)
for (i = PERF_MAX_STACK_DEPTH - 1; i >= 0; i--)
print_addr(ip[i]);
}
printf("\n");
if (count < 6)
printf("\r");
else
printf("\n");
if (key->kernstack == -EEXIST && !warned) {
printf("stackmap collisions seen. Consider increasing size\n");
@ -105,7 +108,7 @@ static void print_stacks(void)
bpf_map_delete_elem(fd, &next_key);
key = next_key;
}
printf("\n");
if (!sys_read_seen || !sys_write_seen) {
printf("BUG kernel stack doesn't contain sys_read() and sys_write()\n");
int_exit(0);
@ -122,24 +125,29 @@ static void test_perf_event_all_cpu(struct perf_event_attr *attr)
{
int nr_cpus = sysconf(_SC_NPROCESSORS_CONF);
int *pmu_fd = malloc(nr_cpus * sizeof(int));
int i;
int i, error = 0;
/* open perf_event on all cpus */
for (i = 0; i < nr_cpus; i++) {
pmu_fd[i] = sys_perf_event_open(attr, -1, i, -1, 0);
if (pmu_fd[i] < 0) {
printf("sys_perf_event_open failed\n");
error = 1;
goto all_cpu_err;
}
assert(ioctl(pmu_fd[i], PERF_EVENT_IOC_SET_BPF, prog_fd[0]) == 0);
assert(ioctl(pmu_fd[i], PERF_EVENT_IOC_ENABLE, 0) == 0);
assert(ioctl(pmu_fd[i], PERF_EVENT_IOC_ENABLE) == 0);
}
system("dd if=/dev/zero of=/dev/null count=5000k");
system("dd if=/dev/zero of=/dev/null count=5000k status=none");
print_stacks();
all_cpu_err:
for (i--; i >= 0; i--)
for (i--; i >= 0; i--) {
ioctl(pmu_fd[i], PERF_EVENT_IOC_DISABLE);
close(pmu_fd[i]);
}
free(pmu_fd);
if (error)
int_exit(0);
}
static void test_perf_event_task(struct perf_event_attr *attr)
@ -150,12 +158,13 @@ static void test_perf_event_task(struct perf_event_attr *attr)
pmu_fd = sys_perf_event_open(attr, 0, -1, -1, 0);
if (pmu_fd < 0) {
printf("sys_perf_event_open failed\n");
return;
int_exit(0);
}
assert(ioctl(pmu_fd, PERF_EVENT_IOC_SET_BPF, prog_fd[0]) == 0);
assert(ioctl(pmu_fd, PERF_EVENT_IOC_ENABLE, 0) == 0);
system("dd if=/dev/zero of=/dev/null count=5000k");
assert(ioctl(pmu_fd, PERF_EVENT_IOC_ENABLE) == 0);
system("dd if=/dev/zero of=/dev/null count=5000k status=none");
print_stacks();
ioctl(pmu_fd, PERF_EVENT_IOC_DISABLE);
close(pmu_fd);
}
@ -175,11 +184,56 @@ static void test_bpf_perf_event(void)
.config = PERF_COUNT_SW_CPU_CLOCK,
.inherit = 1,
};
struct perf_event_attr attr_hw_cache_l1d = {
.sample_freq = SAMPLE_FREQ,
.freq = 1,
.type = PERF_TYPE_HW_CACHE,
.config =
PERF_COUNT_HW_CACHE_L1D |
(PERF_COUNT_HW_CACHE_OP_READ << 8) |
(PERF_COUNT_HW_CACHE_RESULT_ACCESS << 16),
.inherit = 1,
};
struct perf_event_attr attr_hw_cache_branch_miss = {
.sample_freq = SAMPLE_FREQ,
.freq = 1,
.type = PERF_TYPE_HW_CACHE,
.config =
PERF_COUNT_HW_CACHE_BPU |
(PERF_COUNT_HW_CACHE_OP_READ << 8) |
(PERF_COUNT_HW_CACHE_RESULT_MISS << 16),
.inherit = 1,
};
struct perf_event_attr attr_type_raw = {
.sample_freq = SAMPLE_FREQ,
.freq = 1,
.type = PERF_TYPE_RAW,
/* Intel Instruction Retired */
.config = 0xc0,
.inherit = 1,
};
printf("Test HW_CPU_CYCLES\n");
test_perf_event_all_cpu(&attr_type_hw);
test_perf_event_task(&attr_type_hw);
printf("Test SW_CPU_CLOCK\n");
test_perf_event_all_cpu(&attr_type_sw);
test_perf_event_task(&attr_type_sw);
printf("Test HW_CACHE_L1D\n");
test_perf_event_all_cpu(&attr_hw_cache_l1d);
test_perf_event_task(&attr_hw_cache_l1d);
printf("Test HW_CACHE_BPU\n");
test_perf_event_all_cpu(&attr_hw_cache_branch_miss);
test_perf_event_task(&attr_hw_cache_branch_miss);
printf("Test Instruction Retired\n");
test_perf_event_all_cpu(&attr_type_raw);
test_perf_event_task(&attr_type_raw);
printf("*** PASS ***\n");
}
@ -209,7 +263,6 @@ int main(int argc, char **argv)
return 0;
}
test_bpf_perf_event();
int_exit(0);
return 0;
}

28
samples/bpf/tracex6_kern.c
View File

@ -3,22 +3,36 @@
#include <uapi/linux/bpf.h>
#include "bpf_helpers.h"
struct bpf_map_def SEC("maps") my_map = {
struct bpf_map_def SEC("maps") counters = {
.type = BPF_MAP_TYPE_PERF_EVENT_ARRAY,
.key_size = sizeof(int),
.value_size = sizeof(u32),
.max_entries = 32,
.max_entries = 64,
};
struct bpf_map_def SEC("maps") values = {
.type = BPF_MAP_TYPE_HASH,
.key_size = sizeof(int),
.value_size = sizeof(u64),
.max_entries = 64,
};
SEC("kprobe/sys_write")
SEC("kprobe/htab_map_get_next_key")
int bpf_prog1(struct pt_regs *ctx)
{
u64 count;
u32 key = bpf_get_smp_processor_id();
char fmt[] = "CPU-%d %llu\n";
u64 count, *val;
s64 error;
count = bpf_perf_event_read(&my_map, key);
bpf_trace_printk(fmt, sizeof(fmt), key, count);
count = bpf_perf_event_read(&counters, key);
error = (s64)count;
if (error <= -2 && error >= -22)
return 0;
val = bpf_map_lookup_elem(&values, &key);
if (val)
*val = count;
else
bpf_map_update_elem(&values, &key, &count, BPF_NOEXIST);
return 0;
}

180
samples/bpf/tracex6_user.c
View File

@ -1,73 +1,177 @@
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdbool.h>
#include <string.h>
#define _GNU_SOURCE
#include <assert.h>
#include <fcntl.h>
#include <poll.h>
#include <sys/ioctl.h>
#include <linux/perf_event.h>
#include <linux/bpf.h>
#include "libbpf.h"
#include <sched.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/ioctl.h>
#include <sys/resource.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <unistd.h>
#include "bpf_load.h"
#include "libbpf.h"
#include "perf-sys.h"
#define SAMPLE_PERIOD 0x7fffffffffffffffULL
static void check_on_cpu(int cpu, struct perf_event_attr *attr)
{
int pmu_fd, error = 0;
cpu_set_t set;
__u64 value;
/* Move to target CPU */
CPU_ZERO(&set);
CPU_SET(cpu, &set);
assert(sched_setaffinity(0, sizeof(set), &set) == 0);
/* Open perf event and attach to the perf_event_array */
pmu_fd = sys_perf_event_open(attr, -1/*pid*/, cpu/*cpu*/, -1/*group_fd*/, 0);
if (pmu_fd < 0) {
fprintf(stderr, "sys_perf_event_open failed on CPU %d\n", cpu);
error = 1;
goto on_exit;
}
assert(bpf_map_update_elem(map_fd[0], &cpu, &pmu_fd, BPF_ANY) == 0);
assert(ioctl(pmu_fd, PERF_EVENT_IOC_ENABLE, 0) == 0);
/* Trigger the kprobe */
bpf_map_get_next_key(map_fd[1], &cpu, NULL);
/* Check the value */
if (bpf_map_lookup_elem(map_fd[1], &cpu, &value)) {
fprintf(stderr, "Value missing for CPU %d\n", cpu);
error = 1;
goto on_exit;
}
fprintf(stderr, "CPU %d: %llu\n", cpu, value);
on_exit:
assert(bpf_map_delete_elem(map_fd[0], &cpu) == 0 || error);
assert(ioctl(pmu_fd, PERF_EVENT_IOC_DISABLE, 0) == 0 || error);
assert(close(pmu_fd) == 0 || error);
assert(bpf_map_delete_elem(map_fd[1], &cpu) == 0 || error);
exit(error);
}
static void test_perf_event_array(struct perf_event_attr *attr,
const char *name)
{
int i, status, nr_cpus = sysconf(_SC_NPROCESSORS_CONF);
pid_t pid[nr_cpus];
int err = 0;
printf("Test reading %s counters\n", name);
for (i = 0; i < nr_cpus; i++) {
pid[i] = fork();
assert(pid[i] >= 0);
if (pid[i] == 0) {
check_on_cpu(i, attr);
exit(1);
}
}
for (i = 0; i < nr_cpus; i++) {
assert(waitpid(pid[i], &status, 0) == pid[i]);
err |= status;
}
if (err)
printf("Test: %s FAILED\n", name);
}
static void test_bpf_perf_event(void)
{
int nr_cpus = sysconf(_SC_NPROCESSORS_CONF);
int *pmu_fd = malloc(nr_cpus * sizeof(int));
int status, i;
struct perf_event_attr attr_insn_pmu = {
struct perf_event_attr attr_cycles = {
.freq = 0,
.sample_period = SAMPLE_PERIOD,
.inherit = 0,
.type = PERF_TYPE_HARDWARE,
.read_format = 0,
.sample_type = 0,
.config = 0,/* PMU: cycles */
.config = PERF_COUNT_HW_CPU_CYCLES,
};
struct perf_event_attr attr_clock = {
.freq = 0,
.sample_period = SAMPLE_PERIOD,
.inherit = 0,
.type = PERF_TYPE_SOFTWARE,
.read_format = 0,
.sample_type = 0,
.config = PERF_COUNT_SW_CPU_CLOCK,
};
struct perf_event_attr attr_raw = {
.freq = 0,
.sample_period = SAMPLE_PERIOD,
.inherit = 0,
.type = PERF_TYPE_RAW,
.read_format = 0,
.sample_type = 0,
/* Intel Instruction Retired */
.config = 0xc0,
};
struct perf_event_attr attr_l1d_load = {
.freq = 0,
.sample_period = SAMPLE_PERIOD,
.inherit = 0,
.type = PERF_TYPE_HW_CACHE,
.read_format = 0,
.sample_type = 0,
.config =
PERF_COUNT_HW_CACHE_L1D |
(PERF_COUNT_HW_CACHE_OP_READ << 8) |
(PERF_COUNT_HW_CACHE_RESULT_ACCESS << 16),
};
struct perf_event_attr attr_llc_miss = {
.freq = 0,
.sample_period = SAMPLE_PERIOD,
.inherit = 0,
.type = PERF_TYPE_HW_CACHE,
.read_format = 0,
.sample_type = 0,
.config =
PERF_COUNT_HW_CACHE_LL |
(PERF_COUNT_HW_CACHE_OP_READ << 8) |
(PERF_COUNT_HW_CACHE_RESULT_MISS << 16),
};
struct perf_event_attr attr_msr_tsc = {
.freq = 0,
.sample_period = 0,
.inherit = 0,
/* From /sys/bus/event_source/devices/msr/ */
.type = 7,
.read_format = 0,
.sample_type = 0,
.config = 0,
};
for (i = 0; i < nr_cpus; i++) {
pmu_fd[i] = sys_perf_event_open(&attr_insn_pmu, -1/*pid*/, i/*cpu*/, -1/*group_fd*/, 0);
if (pmu_fd[i] < 0) {
printf("event syscall failed\n");
goto exit;
}
test_perf_event_array(&attr_cycles, "HARDWARE-cycles");
test_perf_event_array(&attr_clock, "SOFTWARE-clock");
test_perf_event_array(&attr_raw, "RAW-instruction-retired");
test_perf_event_array(&attr_l1d_load, "HW_CACHE-L1D-load");
bpf_map_update_elem(map_fd[0], &i, &pmu_fd[i], BPF_ANY);
ioctl(pmu_fd[i], PERF_EVENT_IOC_ENABLE, 0);
}
status = system("ls > /dev/null");
if (status)
goto exit;
status = system("sleep 2");
if (status)
goto exit;
exit:
for (i = 0; i < nr_cpus; i++)
close(pmu_fd[i]);
close(map_fd[0]);
free(pmu_fd);
/* below tests may fail in qemu */
test_perf_event_array(&attr_llc_miss, "HW_CACHE-LLC-miss");
test_perf_event_array(&attr_msr_tsc, "Dynamic-msr-tsc");
}
int main(int argc, char **argv)
{
struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
char filename[256];
snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
setrlimit(RLIMIT_MEMLOCK, &r);
if (load_bpf_file(filename)) {
printf("%s", bpf_log_buf);
return 1;
}
test_bpf_perf_event();
read_trace_pipe();
return 0;
}

11
tools/include/uapi/linux/bpf.h
View File

@ -313,8 +313,11 @@ union bpf_attr {
* @flags: room for future extensions
* Return: 0 on success or negative error
*
* u64 bpf_perf_event_read(&map, index)
* Return: Number events read or error code
* u64 bpf_perf_event_read(map, flags)
* read perf event counter value
* @map: pointer to perf_event_array map
* @flags: index of event in the map or bitmask flags
* Return: value of perf event counter read or error code
*
* int bpf_redirect(ifindex, flags)
* redirect to another netdev
@ -328,11 +331,11 @@ union bpf_attr {
* @skb: pointer to skb
* Return: realm if != 0
*
* int bpf_perf_event_output(ctx, map, index, data, size)
* int bpf_perf_event_output(ctx, map, flags, data, size)
* output perf raw sample
* @ctx: struct pt_regs*
* @map: pointer to perf_event_array map
* @index: index of event in the map
* @flags: index of event in the map or bitmask flags
* @data: data on stack to be output as raw data
* @size: size of data
* Return: 0 on success or negative error