runtime: print irrelevant IDs as nil in schedtrace

We currently print these as -1, but some are technically uint64. We can
be more explicit about their irrelevance by printing 'nil' rather than
-1.

Change-Id: I267fd8830564c75032bfe9176af59047f5a90202
Reviewed-on: https://go-review.googlesource.com/c/go/+/419441
Reviewed-by: Austin Clements <austin@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Michael Pratt <mpratt@google.com>

diff --git a/src/runtime/proc.go b/src/runtime/proc.go
index ff9caed2126870d41c508ae32c233803f3eee53c..2ebca7b2679d2cb13a98189bc999c5144a733632 100644 (file)
--- a/src/runtime/proc.go
+++ b/src/runtime/proc.go
@@ -5421,11 +5421,13 @@ func schedtrace(detailed bool) {
                h := atomic.Load(&pp.runqhead)
                t := atomic.Load(&pp.runqtail)
                if detailed {
-                       id := int64(-1)
+                       print("  P", i, ": status=", pp.status, " schedtick=", pp.schedtick, " syscalltick=", pp.syscalltick, " m=")
                        if mp != nil {
-                               id = mp.id
+                               print(mp.id)
+                       } else {
+                               print("nil")
                        }
-                       print("  P", i, ": status=", pp.status, " schedtick=", pp.schedtick, " syscalltick=", pp.syscalltick, " m=", id, " runqsize=", t-h, " gfreecnt=", pp.gFree.n, " timerslen=", len(pp.timers), "\n")
+                       print(" runqsize=", t-h, " gfreecnt=", pp.gFree.n, " timerslen=", len(pp.timers), "\n")
                } else {
                        // In non-detailed mode format lengths of per-P run queues as:
                        // [len1 len2 len3 len4]
@@ -5447,35 +5449,41 @@ func schedtrace(detailed bool) {
 
        for mp := allm; mp != nil; mp = mp.alllink {
                pp := mp.p.ptr()
-               gp := mp.curg
-               lockedg := mp.lockedg.ptr()
-               id1 := int32(-1)
+               print("  M", mp.id, ": p=")
                if pp != nil {
-                       id1 = pp.id
+                       print(pp.id)
+               } else {
+                       print("nil")
                }
-               id2 := int64(-1)
-               if gp != nil {
-                       id2 = int64(gp.goid)
+               print(" curg=")
+               if mp.curg != nil {
+                       print(mp.curg.goid)
+               } else {
+                       print("nil")
                }
-               id3 := int64(-1)
-               if lockedg != nil {
-                       id3 = int64(lockedg.goid)
+               print(" mallocing=", mp.mallocing, " throwing=", mp.throwing, " preemptoff=", mp.preemptoff, " locks=", mp.locks, " dying=", mp.dying, " spinning=", mp.spinning, " blocked=", mp.blocked, " lockedg=")
+               if lockedg := mp.lockedg.ptr(); lockedg != nil {
+                       print(lockedg.goid)
+               } else {
+                       print("nil")
                }
-               print("  M", mp.id, ": p=", id1, " curg=", id2, " mallocing=", mp.mallocing, " throwing=", mp.throwing, " preemptoff=", mp.preemptoff, " locks=", mp.locks, " dying=", mp.dying, " spinning=", mp.spinning, " blocked=", mp.blocked, " lockedg=", id3, "\n")
+               print("\n")
        }
 
        forEachG(func(gp *g) {
-               mp := gp.m
-               lockedm := gp.lockedm.ptr()
-               id1 := int64(-1)
-               if mp != nil {
-                       id1 = mp.id
+               print("  G", gp.goid, ": status=", readgstatus(gp), "(", gp.waitreason.String(), ") m=")
+               if gp.m != nil {
+                       print(gp.m.id)
+               } else {
+                       print("nil")
                }
-               id2 := int64(-1)
-               if lockedm != nil {
-                       id2 = lockedm.id
+               print(" lockedm=")
+               if lockedm := gp.lockedm.ptr(); lockedm != nil {
+                       print(lockedm.id)
+               } else {
+                       print("nil")
                }
-               print("  G", gp.goid, ": status=", readgstatus(gp), "(", gp.waitreason.String(), ") m=", id1, " lockedm=", id2, "\n")
+               print("\n")
        })
        unlock(&sched.lock)
 }