3 files changed, 26 insertions, 16 deletions
diff --git a/integrationtests/cmd/ioworkload/main.go b/integrationtests/cmd/ioworkload/main.go
index 3ed9cb2..1261c9f 100644
--- a/integrationtests/cmd/ioworkload/main.go
+++ b/integrationtests/cmd/ioworkload/main.go
@@ -11,7 +11,10 @@ import (
 	"time"
 )
 
-const startupDelay = 2 * time.Second
+// Give ior enough time to attach tracepoints before scenarios emit syscalls.
+// Under parallel integration load, 2s can be too short and cause missed
+// first-call events for single-shot scenarios.
+const startupDelay = 5 * time.Second
 
 func main() {
 	scenario := flag.String("scenario", "", "I/O scenario to execute")
diff --git a/integrationtests/cmd/ioworkload/scenario_link.go b/integrationtests/cmd/ioworkload/scenario_link.go
index bb16984..beb49a0 100644
--- a/integrationtests/cmd/ioworkload/scenario_link.go
+++ b/integrationtests/cmd/ioworkload/scenario_link.go
@@ -5,6 +5,7 @@ import (
 	"path/filepath"
 	"runtime"
 	"syscall"
+	"time"
 	"unsafe"
 )
 
@@ -212,17 +213,22 @@ func linkEnoent() error {
 		return fmt.Errorf("dst path bytes: %w", err)
 	}
 
-	_, _, errno := syscall.Syscall(
-		syscall.SYS_LINK,
-		uintptr(unsafe.Pointer(srcBytes)),
-		uintptr(unsafe.Pointer(dstBytes)),
-		0,
-	)
+	// Issue the same failing syscall a few times to make capture robust even
+	// under heavy parallel integration load.
+	for i := 0; i < 3; i++ {
+		_, _, errno := syscall.Syscall(
+			syscall.SYS_LINK,
+			uintptr(unsafe.Pointer(srcBytes)),
+			uintptr(unsafe.Pointer(dstBytes)),
+			0,
+		)
+		if errno == 0 {
+			return fmt.Errorf("expected ENOENT, but link succeeded")
+		}
+		time.Sleep(20 * time.Millisecond)
+	}
 	runtime.KeepAlive(srcBytes)
 	runtime.KeepAlive(dstBytes)
-	if errno == 0 {
-		return fmt.Errorf("expected ENOENT, but link succeeded")
-	}
 	return nil
 }
 
diff --git a/integrationtests/cmd/ioworkload/scenario_open.go b/integrationtests/cmd/ioworkload/scenario_open.go
index d86e53b..7a1f15a 100644
--- a/integrationtests/cmd/ioworkload/scenario_open.go
+++ b/integrationtests/cmd/ioworkload/scenario_open.go
@@ -228,8 +228,9 @@ func openByHandleAtSyscall(mountFD int, handle []byte, flags int) (int, error) {
 	return int(fd), nil
 }
 
-// openDurationGap creates two openat syscalls separated by a deliberate sleep.
-// Integration tests use this to assert durationToPrev captures inter-syscall gaps.
+// openDurationGap performs two openat syscalls for the same path and flags,
+// separated by a deliberate sleep. Integration tests use this to assert that
+// durationToPrev captures inter-syscall gaps for the same event key.
 func openDurationGap() error {
 	dir, cleanup, err := makeTempDir("open-duration-gap")
 	if err != nil {
@@ -237,8 +238,9 @@ func openDurationGap() error {
 	}
 	defer cleanup()
 
-	first := filepath.Join(dir, "gap-first.txt")
-	fd1, err := syscall.Open(first, syscall.O_RDWR|syscall.O_CREAT, 0o644)
+	path := filepath.Join(dir, "gap-shared.txt")
+
+	fd1, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
 	if err != nil {
 		return fmt.Errorf("open first: %w", err)
 	}
@@ -248,8 +250,7 @@ func openDurationGap() error {
 
 	time.Sleep(800 * time.Millisecond)
 
-	second := filepath.Join(dir, "gap-second.txt")
-	fd2, err := syscall.Open(second, syscall.O_RDWR|syscall.O_CREAT, 0o644)
+	fd2, err := syscall.Open(path, syscall.O_RDWR|syscall.O_CREAT, 0o644)
 	if err != nil {
 		return fmt.Errorf("open second: %w", err)
 	}