[release-branch.go1.22] cmd/trace/v2,internal/trace: use correct frame for identifying goroutines
To determine the identity of a goroutine for displaying in the trace UI,
we should use the root frame from a call stack. This will be the
starting function for the goroutine and is the same for each call stack
from a given goroutine. The new tracer no longer includes starting PCs
for goroutines which existed at the start of tracing, so we can't use a
PC for grouping together goroutines any more. Instead, we just use the
name of the entry function for grouping.
For #65574
Fixes #65577
Change-Id: I5324653316f1acf0ab90c30680f181060ea45dd7
Reviewed-on: https://go-review.googlesource.com/c/go/+/562455
Reviewed-by: Michael Knyszek <mknyszek@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: David Chase <drchase@google.com>
(cherry picked from commit
a51713103b5769a792b691e313254b7806855fa6)
Reviewed-on: https://go-review.googlesource.com/c/go/+/562558
Reviewed-by: Michael Pratt <mpratt@google.com>