cmd/trace: use the focustask mode for user task/region trace views
The taskid mode is based on the goroutine-oriented trace view,
which displays each goroutine as a separate row. This is good when
inspecting the interaction and timeline among related goroutines,
and the user region information (associated with each goroutine)
in detail, but when many goroutines are involved, this mode does
not scale.
The focustask mode is based on the default trace view with the
user task hierarchy at the top. Each row is a P and there are only
a handful number of Ps in most cases, so browsers can handle
this mode more gracefully. But, I had difficulty in displaying
the user region information (because a goroutine can start/stop/
migrate across Ps, and visualizing the stack of regions nicely
was complicated). It may be doable, but it's a work.
This CL surfaces the hidden focustask mode. Moreover, use it
as the default user task view mode. The taskid mode can be still
accessible through 'goroutine view' links.
Unlike taskid-based user annotation view that extends goroutine-based
trace view, the focustask view
Change-Id: Ib691a5e1dd14695fa70a0ae67bff62817025e8c3
Reviewed-on: https://go-review.googlesource.com/c/go/+/227921 Reviewed-by: Michael Matloob <matloob@golang.org>
Run-TryBot: Hyang-Ah Hana Kim <hyangah@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>