1 // Copyright 2023 The Go Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style
3 // license that can be found in the LICENSE file.
5 // Regression test for an issue found in development.
7 // The core of the issue is that if generation counters
8 // aren't considered as part of sequence numbers, then
9 // it's possible to accidentally advance without a
12 // The situation is one in which it just so happens that
13 // an event on the frontier for a following generation
14 // has a sequence number exactly one higher than the last
15 // sequence number for e.g. a goroutine in the previous
16 // generation. The parser should wait to find a GoStatus
17 // event before advancing into the next generation at all.
18 // It turns out this situation is pretty rare; the GoStatus
19 // event almost always shows up first in practice. But it
20 // can and did happen.
26 "internal/trace/v2/event/go122"
27 testgen "internal/trace/v2/internal/testgen/go122"
34 func gen(t *testgen.Trace) {
37 // A running goroutine blocks.
38 b10 := g1.Batch(trace.ThreadID(0), 0)
39 b10.Event("ProcStatus", trace.ProcID(0), go122.ProcRunning)
40 b10.Event("GoStatus", trace.GoID(1), trace.ThreadID(0), go122.GoRunning)
41 b10.Event("GoStop", "whatever", testgen.NoStack)
43 // The running goroutine gets unblocked.
44 b11 := g1.Batch(trace.ThreadID(1), 0)
45 b11.Event("ProcStatus", trace.ProcID(1), go122.ProcRunning)
46 b11.Event("GoStart", trace.GoID(1), testgen.Seq(1))
47 b11.Event("GoStop", "whatever", testgen.NoStack)
51 // Start running the goroutine, but later.
52 b21 := g2.Batch(trace.ThreadID(1), 3)
53 b21.Event("ProcStatus", trace.ProcID(1), go122.ProcRunning)
54 b21.Event("GoStart", trace.GoID(1), testgen.Seq(2))
56 // The goroutine starts running, then stops, then starts again.
57 b20 := g2.Batch(trace.ThreadID(0), 5)
58 b20.Event("ProcStatus", trace.ProcID(0), go122.ProcRunning)
59 b20.Event("GoStatus", trace.GoID(1), trace.ThreadID(0), go122.GoRunnable)
60 b20.Event("GoStart", trace.GoID(1), testgen.Seq(1))
61 b20.Event("GoStop", "whatever", testgen.NoStack)