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|
// +build linux
package perf
import (
"fmt"
"strconv"
"strings"
"unsafe"
"golang.org/x/sys/unix"
)
const (
// PERF_TYPE_TRACEPOINT is a kernel tracepoint.
PERF_TYPE_TRACEPOINT = 2
)
// AvailableEvents returns a mapping of available subsystems and their
// corresponding list of available events.
func AvailableEvents() (map[string][]string, error) {
events := map[string][]string{}
// BUG(hodgesds): this should ideally check mounts for debugfs
rawEvents, err := fileToStrings(TracingDir + "/available_events")
// Events are colon delimited by type so parse the type and add sub
// events appropriately.
if err != nil {
return events, err
}
for _, rawEvent := range rawEvents {
splits := strings.Split(rawEvent, ":")
if len(splits) <= 1 {
continue
}
eventTypeEvents, found := events[splits[0]]
if found {
events[splits[0]] = append(eventTypeEvents, splits[1])
continue
}
events[splits[0]] = []string{splits[1]}
}
return events, err
}
// AvailableSubsystems returns a slice of available subsystems.
func AvailableSubsystems() ([]string, error) {
subsystems := []string{}
// BUG(hodgesds): this should ideally check mounts for debugfs
rawEvents, err := fileToStrings(TracingDir + "/available_events")
// Events are colon delimited by type so parse the type and add sub
// events appropriately.
if err != nil {
return subsystems, err
}
for _, rawEvent := range rawEvents {
splits := strings.Split(rawEvent, ":")
if len(splits) <= 1 {
continue
}
subsystems = append(subsystems, splits[0])
}
return subsystems, nil
}
// AvailableTracers returns the list of available tracers.
func AvailableTracers() ([]string, error) {
return fileToStrings(TracingDir + "/available_tracers")
}
// CurrentTracer returns the current tracer.
func CurrentTracer() (string, error) {
res, err := fileToStrings(TracingDir + "/current_tracer")
return res[0], err
}
// GetTracepointConfig is used to get the configuration for a trace event.
func GetTracepointConfig(subsystem, event string) (uint64, error) {
res, err := fileToStrings(
TracingDir + fmt.Sprintf("/events/%s/%s/id", subsystem, event))
if err != nil {
return 0, err
}
return strconv.ParseUint(res[0], 10, 64)
}
// ProfileTracepoint is used to profile a kernel tracepoint event for a
// specific PID. Events can be listed with `perf list` for Tracepoint Events or
// in the /sys/kernel/debug/tracing/events directory with the kind being the
// directory and the event being the subdirectory.
func ProfileTracepoint(subsystem, event string, pid, cpu int, opts ...int) (BPFProfiler, error) {
config, err := GetTracepointConfig(subsystem, event)
if err != nil {
return nil, err
}
eventAttr := &unix.PerfEventAttr{
Type: PERF_TYPE_TRACEPOINT,
Config: config,
Size: uint32(unsafe.Sizeof(unix.PerfEventAttr{})),
Bits: unix.PerfBitDisabled | unix.PerfBitExcludeHv,
Read_format: unix.PERF_FORMAT_TOTAL_TIME_RUNNING | unix.PERF_FORMAT_TOTAL_TIME_ENABLED,
Sample_type: PERF_SAMPLE_IDENTIFIER,
}
var eventOps int
if len(opts) > 0 {
eventOps = opts[0]
}
fd, err := unix.PerfEventOpen(
eventAttr,
pid,
cpu,
-1,
eventOps,
)
if err != nil {
return nil, err
}
return &profiler{
fd: fd,
}, nil
}
// TracepointEventAttr is used to return an PerfEventAttr for a trace event.
func TracepointEventAttr(subsystem, event string) (*unix.PerfEventAttr, error) {
config, err := GetTracepointConfig(subsystem, event)
if err != nil {
return nil, err
}
return &unix.PerfEventAttr{
Type: PERF_TYPE_TRACEPOINT,
Config: config,
Size: uint32(unsafe.Sizeof(unix.PerfEventAttr{})),
Bits: unix.PerfBitDisabled | unix.PerfBitExcludeHv,
Read_format: unix.PERF_FORMAT_TOTAL_TIME_RUNNING | unix.PERF_FORMAT_TOTAL_TIME_ENABLED,
Sample_type: PERF_SAMPLE_IDENTIFIER,
}, nil
}
|
