Remove timeoutWait due to improved scheduler handling

proctl/proctl_linux_amd64.go

@@ -9,7 +9,6 @@ import (
 	"os/exec"
 	"sync"
 	"syscall"
-	"time"
 
 	"github.com/derekparker/delve/dwarf/frame"
 	"github.com/derekparker/delve/vendor/elf"
@@ -319,11 +318,7 @@ func (dbp *DebuggedProcess) Continue() error {
 	for _, thread := range dbp.Threads {
 		err := thread.Continue()
 		if err != nil {
-			// TODO(dp): There are some coordination issues
-			// here that need to be resolved.
-			if _, ok := err.(TimeoutError); !ok && err != syscall.ESRCH {
-				return err
-			}
+			return err
 		}
 	}
 
@@ -558,57 +553,6 @@ type waitstats struct {
 	status *syscall.WaitStatus
 }
 
-type TimeoutError struct {
-	pid int
-}
-
-func (err TimeoutError) Error() string {
-	return fmt.Sprintf("timeout waiting for %d", err.pid)
-}
-
-// TODO(dp): this is a hacky, racy implementation. Ideally this method will
-// become defunct and replaced by a non-blocking incremental sleeping wait.
-// The purpose is to detect whether a thread is sleeping. However, this is
-// tricky because a thread can be sleeping due to being a blocked M in the
-// scheduler or sleeping due to a user calling sleep.
-func timeoutWait(thread *ThreadContext, options int) (int, *syscall.WaitStatus, error) {
-	var (
-		statchan = make(chan *waitstats)
-		errchan  = make(chan error)
-	)
-
-	ps, err := parseProcessStatus(thread.Id)
-	if err != nil {
-		return -1, nil, err
-	}
-
-	if ps.state == STATUS_SLEEPING {
-		return 0, nil, nil
-	}
-
-	go func(pid int, statchan chan *waitstats, errchan chan error) {
-		wpid, status, err := wait(pid, 0)
-		if err != nil {
-			errchan <- fmt.Errorf("wait err %s %d", err, pid)
-		}
-
-		statchan <- &waitstats{pid: wpid, status: status}
-	}(thread.Id, statchan, errchan)
-
-	select {
-	case s := <-statchan:
-		return s.pid, s.status, nil
-	case <-time.After(10 * time.Millisecond):
-		if err := syscall.Tgkill(thread.Process.Pid, thread.Id, syscall.SIGSTOP); err != nil {
-			return -1, nil, err
-		}
-		<-statchan
-		return 0, nil, TimeoutError{thread.Id}
-	case err := <-errchan:
-		return -1, nil, err
-	}
-}
-
 func wait(pid, options int) (int, *syscall.WaitStatus, error) {
 	var status syscall.WaitStatus
 	wpid, err := syscall.Wait4(pid, &status, syscall.WALL|options, nil)

proctl/proctl_test.go

@@ -102,9 +102,7 @@ func TestBreakPoint(t *testing.T) {
 		}
 
 		err = p.Step()
-		if _, ok := err.(proctl.TimeoutError); !ok {
-			assertNoError(err, t, "Step()")
-		}
+		assertNoError(err, t, "Step()")
 
 		pc, err = p.CurrentPC()
 		if err != nil {

proctl/threads_linux_amd64.go

@@ -170,7 +170,7 @@ func (thread *ThreadContext) Step() (err error) {
 		return fmt.Errorf("step failed: %s", err.Error())
 	}
 
-	_, _, err = timeoutWait(thread, 0)
+	_, _, err = wait(thread.Id, 0)
 	if err != nil {
 		return err
 	}