Re: [Qemu-devel] [RFC PATCH 04/21] trace: enable the exec_tb trace events

[Emilio G. Cota]

On Fri, Oct 05, 2018 at 16:48:53 +0100, Alex Bennée wrote:
> Our performance isn't so critical that we can't spare a simple flag
> check when we exec a TB considering everything else we check in the
> outer loop.

[I know this is just done to illustrate how function names
in plugins can bind to tracing calls, but someone might
get confused by expecting more from "exec_tb" than it
actually does.]

This flag check costs nothing because "exec_tb" is
almost never called. The way it works right now, we
need -d nochain for "exec_tb" to actually generate
an event every time a TB executes.

IMO an eventual plugin API should let plugins decide whether
to subscribe to the execution of a particular TB, when
said TB is being translated, instead of providing
an all-or-nothing switch.

Thanks,

                E.