bpfmaps

Documentation

Index

• Constants
• Variables
• type CombinedStack
• type Maps
  • func New(logger log.Logger, reg prometheus.Registerer, ...) (*Maps, error)
  • func (m *Maps) AddUnwindTableForProcess(pid int, executableMappings unwind.ExecutableMappings, ...) error
  • func (m *Maps) AddUnwinderInfo(pid int, unwinderInfo runtime.UnwinderInfo) error
  • func (m *Maps) AdjustMapSizes(debugEnabled bool, unwindTableShards, eventsBufferSize uint32) error
  • func (m *Maps) ByteOrder() binary.ByteOrder
  • func (m *Maps) Close() error
  • func (m *Maps) Create() error
  • func (m *Maps) FinalizeProfileLoop() error
  • func (m *Maps) GetUnwindFailedReasons() (map[int]profiler.UnwindFailedReasons, error)
  • func (m *Maps) InterpreterSymbolTable() (profile.InterpreterSymbolTable, error)
  • func (m *Maps) PersistUnwindTable() error
  • func (m *Maps) ReadStack(stackID uint64, stack []profile.StackFrame) error
  • func (m *Maps) ReadStackCount(keyBytes []byte) (uint64, error)
  • func (m *Maps) RefreshProcessInfo(pid int, shouldUseFPByDefault bool)
  • func (m *Maps) ReuseMaps() error
  • func (m *Maps) SetDebugPIDs(pids []int) error
  • func (m *Maps) SetUnwinderData() error
  • func (m *Maps) UpdateTailCallsMap() error
• type Metrics
  • func NewMetrics(reg prometheus.Registerer) *Metrics
• type ProcessCache
  • func NewProcessCache(logger log.Logger, reg prometheus.Registerer) *ProcessCache

Constants

const (
	StackCountsMapName  = "stack_counts"
	CustomLabelsMapName = "custom_labels"

	StackTracesMapName = "stack_traces"

	// rbperf maps.
	RubyPIDToRubyInterpreterInfoMapName = "pid_to_interpreter_info"
	RubyVersionSpecificOffsetMapName    = "version_specific_offsets"

	// pyperf maps.
	PythonPIDToInterpreterInfoMapName  = "pid_to_interpreter_info"
	PythonVersionSpecificOffsetMapName = "version_specific_offsets"
	PythonGlibcOffsetsMapName          = "glibc_offsets"
	PythonMuslOffsetsMapName           = "musl_offsets"

	// jvm maps.
	JavaPIDToVMInfoMapName           = "pid_to_vm_info"
	JavaVersionSpecificOffsetMapName = "version_specific_offsets"

	// native runtime info maps
	NativePIDToRuntimeInfoMapName = "pid_to_runtime_info"

	UnwindInfoChunksMapName    = "unwind_info_chunks"
	UnwindTablesMapName        = "unwind_tables"
	ProcessInfoMapName         = "process_info"
	ProgramsMapName            = "programs"
	PerCPUStatsMapName         = "percpu_stats"
	UnwindFailedReasonsMapName = "unwind_failed_reasons"

	// With the current compact rows, the max items we can store in the kernels
	// we have tested is 262k per map, which we rounded it down to 250k.
	MaxUnwindShards = 30 // How many unwind table shards we have.

	MaxCachedProcesses = 100_000
)

const (
	RequestUnwindInformation byte = iota
	RequestProcessMappings
	RequestRefreshProcInfo
	RequestRead
)

const (
	StackDepth = 128 // Always needs to be sync with MAX_STACK_DEPTH + 1 in BPF program. The +1 is because we can have an extra error frame.

)

Variables

var (
	ErrMissing                   = errors.New("missing stack trace")
	ErrUnwindFailed              = errors.New("stack ID is 0, probably stack unwinding failed")
	ErrUnrecoverable             = errors.New("unrecoverable error")
	ErrTooManyExecutableMappings = errors.New("too many executable mappings")
	ErrNeedMoreProfilingRounds   = errors.New("not enough profiling rounds with this unwind info")
)

Types

type CombinedStack

type CombinedStack [tripleStackDepth]profile.StackFrame

type Maps

type Maps struct {
	StackCounts *libbpf.BPFMap

	CustomLabels *libbpf.BPFMap
	// contains filtered or unexported fields
}

func New

func New(
	logger log.Logger,
	reg prometheus.Registerer,
	modules map[bpfprograms.ProfilerModuleType]*libbpf.Module,
	ofp *objectfile.Pool,
	processCache *ProcessCache,
	syncedUnwinderInfo *cache.Cache[int, runtime.UnwinderInfo],
	finder *debuginfo.Finder,
) (*Maps, error)

func (*Maps) AddUnwindTableForProcess

func (m *Maps) AddUnwindTableForProcess(pid int, executableMappings unwind.ExecutableMappings, checkCache, shouldUseFPByDefault bool) error

1. Find executable sections 2. For each section, generate compact table 3. Add table to maps 4. Add map metadata to process

func (*Maps) AddUnwinderInfo

func (m *Maps) AddUnwinderInfo(pid int, unwinderInfo runtime.UnwinderInfo) error

AddUnwinderInfo adds the unwinder information to the relevant BPF maps. It is a lookup table for the BPF program to find the unwinder information for corresponding process' runtime.

Process information is stored in a separate map and needs to be updated separately.

func (*Maps) AdjustMapSizes

func (m *Maps) AdjustMapSizes(debugEnabled bool, unwindTableShards, eventsBufferSize uint32) error

AdjustMapSizes updates the amount of unwind shards.

Note: It must be called before `BPFLoadObject()`.

func (*Maps) ByteOrder

func (m *Maps) ByteOrder() binary.ByteOrder

func (*Maps) Close

func (m *Maps) Close() error

Close closes all the resources associated with the maps.

func (*Maps) Create

func (m *Maps) Create() error

func (*Maps) FinalizeProfileLoop

func (m *Maps) FinalizeProfileLoop() error

func (*Maps) GetUnwindFailedReasons

func (m *Maps) GetUnwindFailedReasons() (map[int]profiler.UnwindFailedReasons, error)

func (*Maps) InterpreterSymbolTable

func (m *Maps) InterpreterSymbolTable() (profile.InterpreterSymbolTable, error)

PERF: This code presents (at least) presents two possible performance opportunities that we should measure.

- Preallocating the lookup table. - Batch the BPF map calls to read and update them.

func (*Maps) PersistUnwindTable

func (m *Maps) PersistUnwindTable() error

PersistUnwindTable calls persistUnwindTable but holding the mutex to ensure that shared state is mutated safely.

Never use this function from addUnwindTableForProcess, as it holds this same mutex.

func (*Maps) ReadStack

func (m *Maps) ReadStack(stackID uint64, stack []profile.StackFrame) error

ReadStack reads the walked stacktrace into the given buffer.

func (*Maps) ReadStackCount

func (m *Maps) ReadStackCount(keyBytes []byte) (uint64, error)

ReadStackCount reads the value of the given key from the counts ebpf map.

func (*Maps) RefreshProcessInfo

func (m *Maps) RefreshProcessInfo(pid int, shouldUseFPByDefault bool)

RefreshProcessInfo updates the process information such as mappings and unwind information if the executable mappings have changed.

func (*Maps) ReuseMaps

func (m *Maps) ReuseMaps() error

func (*Maps) SetDebugPIDs

func (m *Maps) SetDebugPIDs(pids []int) error

func (*Maps) SetUnwinderData

func (m *Maps) SetUnwinderData() error

func (*Maps) UpdateTailCallsMap

func (m *Maps) UpdateTailCallsMap() error

type Metrics

type Metrics struct {
	// contains filtered or unexported fields
}

func NewMetrics

func NewMetrics(reg prometheus.Registerer) *Metrics

type ProcessCache

type ProcessCache struct {
	*cache.Cache[int, uint64]
}

func NewProcessCache

func NewProcessCache(logger log.Logger, reg prometheus.Registerer) *ProcessCache