diff options
Diffstat (limited to 'internal/eventloop.go')
| -rw-r--r-- | internal/eventloop.go | 129 |
1 files changed, 98 insertions, 31 deletions
diff --git a/internal/eventloop.go b/internal/eventloop.go index d0f861d..62ab148 100644 --- a/internal/eventloop.go +++ b/internal/eventloop.go @@ -7,6 +7,7 @@ import ( "fmt" "os" "path/filepath" + "sync" "syscall" "time" @@ -38,13 +39,16 @@ type eventLoop struct { pendingHandles map[uint32]string // map of TID to pathname from name_to_handle_at files map[int32]file.File // Track all open files by file descriptor.. comms map[uint32]string // Program or thread name of the current Tid. - prevPairTimes map[uint32]uint64 // Previous event's time (to calculate time differences between two events) - rawHandlers map[EventType]rawEventHandler - flamegraph flamegraph.IorDataCollector // Storing all paths in a map structure for analysis - liveTrie *flamegraph.LiveTrie - printCb func(ep *event.Pair) // Callback to print the event - warningCb func(message string) // Optional callback for non-fatal event processing warnings - cfg eventLoopConfig + commsMu sync.RWMutex + // pendingCommLookups deduplicates async /proc comm lookups by TID. + pendingCommLookups map[uint32]struct{} + prevPairTimes map[uint32]uint64 // Previous event's time (to calculate time differences between two events) + rawHandlers map[EventType]rawEventHandler + flamegraph flamegraph.IorDataCollector // Storing all paths in a map structure for analysis + liveTrie *flamegraph.LiveTrie + printCb func(ep *event.Pair) // Callback to print the event + warningCb func(message string) // Optional callback for non-fatal event processing warnings + cfg eventLoopConfig // Statistics numTracepoints uint @@ -57,17 +61,18 @@ type eventLoop struct { func newEventLoop(cfg eventLoopConfig) *eventLoop { el := &eventLoop{ - filter: newEventFilter(), - enterEvs: make(map[uint32]*event.Pair), - pendingHandles: make(map[uint32]string), - files: make(map[int32]file.File), - comms: make(map[uint32]string), - prevPairTimes: make(map[uint32]uint64), - rawHandlers: make(map[EventType]rawEventHandler), - printCb: func(ep *event.Pair) { fmt.Println(ep); ep.Recycle() }, - flamegraph: flamegraph.New(), - cfg: cfg, - done: make(chan struct{}), + filter: newEventFilter(), + enterEvs: make(map[uint32]*event.Pair), + pendingHandles: make(map[uint32]string), + files: make(map[int32]file.File), + comms: make(map[uint32]string), + pendingCommLookups: make(map[uint32]struct{}), + prevPairTimes: make(map[uint32]uint64), + rawHandlers: make(map[EventType]rawEventHandler), + printCb: func(ep *event.Pair) { fmt.Println(ep); ep.Recycle() }, + flamegraph: flamegraph.New(), + cfg: cfg, + done: make(chan struct{}), } el.initRawHandlers() if cfg.liveFlamegraph { @@ -78,11 +83,26 @@ func newEventLoop(cfg eventLoopConfig) *eventLoop { } func (e *eventLoop) seedTrackedPidComm() { - pid := e.cfg.pidFilter - if pid <= 0 { - return + candidates := []uint32{uint32(os.Getpid()), uint32(os.Getppid())} + if pid := e.cfg.pidFilter; pid > 0 { + candidates = append(candidates, uint32(pid)) + } + + seen := make(map[uint32]struct{}, len(candidates)) + for _, tid := range candidates { + if tid == 0 { + continue + } + if _, ok := seen[tid]; ok { + continue + } + seen[tid] = struct{}{} + if comm := resolveCommFromProc(tid); comm != "" { + e.setCachedComm(tid, comm) + continue + } + e.queueCommLookup(tid) } - _ = e.comm(uint32(pid)) } func (e *eventLoop) stats() string { @@ -248,10 +268,8 @@ func (e *eventLoop) initRawHandlers() { func (e *eventLoop) tracepointEntered(enterEv event.Event) { tid := enterEv.GetTid() - // Cache comm as early as possible to reduce races for short-lived processes. - if _, ok := e.comms[tid]; !ok { - _ = e.comm(tid) - } + // Schedule comm lookup as early as possible to reduce races for short-lived processes. + e.queueCommLookup(tid) if !e.filter.commFilterEnable { e.enterEvs[tid] = event.NewPair(enterEv) return @@ -262,7 +280,7 @@ func (e *eventLoop) tracepointEntered(enterEv event.Event) { e.enterEvs[tid] = event.NewPair(enterEv) default: // Only, when we have a comm name - if _, ok := e.comms[tid]; ok { + if _, ok := e.cachedComm(tid); ok { e.enterEvs[tid] = event.NewPair(enterEv) } else { // Probably not an issue. @@ -340,7 +358,7 @@ func (e *eventLoop) handleOpenExit(ep *event.Pair, openEv *OpenEvent) bool { // Keep path information for failed opens so error scenarios remain observable. ep.File = file.NewPathname(openEv.Filename[:]) } - e.comms[openEv.Tid] = comm + e.setCachedComm(openEv.Tid, comm) return true } @@ -599,9 +617,60 @@ func (e *eventLoop) notifyWarning(message string) { } func (e *eventLoop) comm(tid uint32) string { - if comm, ok := e.comms[tid]; ok { + if comm, ok := e.cachedComm(tid); ok { return comm } + e.queueCommLookup(tid) + return "" +} + +func (e *eventLoop) cachedComm(tid uint32) (string, bool) { + e.commsMu.RLock() + defer e.commsMu.RUnlock() + comm, ok := e.comms[tid] + return comm, ok +} + +func (e *eventLoop) setCachedComm(tid uint32, comm string) { + if comm == "" { + return + } + e.commsMu.Lock() + e.comms[tid] = comm + e.commsMu.Unlock() +} + +func (e *eventLoop) queueCommLookup(tid uint32) { + if tid == 0 { + return + } + e.commsMu.Lock() + if _, ok := e.comms[tid]; ok { + e.commsMu.Unlock() + return + } + if e.pendingCommLookups == nil { + e.pendingCommLookups = make(map[uint32]struct{}) + } + if _, ok := e.pendingCommLookups[tid]; ok { + e.commsMu.Unlock() + return + } + e.pendingCommLookups[tid] = struct{}{} + e.commsMu.Unlock() + + go func() { + comm := resolveCommFromProc(tid) + e.commsMu.Lock() + delete(e.pendingCommLookups, tid) + if comm != "" { + e.comms[tid] = comm + } + e.commsMu.Unlock() + }() +} + +func resolveCommFromProc(tid uint32) string { commPath := fmt.Sprintf("/proc/%d/comm", tid) if data, err := os.ReadFile(commPath); err == nil { comm := string(data) @@ -609,13 +678,11 @@ func (e *eventLoop) comm(tid uint32) string { comm = comm[:len(comm)-1] } if comm != "" { - e.comms[tid] = comm return comm } } if linkName, err := os.Readlink(fmt.Sprintf("/proc/%d/exe", tid)); err == nil { linkName = filepath.Base(linkName) - e.comms[tid] = linkName return linkName } return "" |