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Re: [Qemu-devel] [RFC PATCH 04/21] trace: enable the exec_tb trace event
From: |
Emilio G. Cota |
Subject: |
Re: [Qemu-devel] [RFC PATCH 04/21] trace: enable the exec_tb trace events |
Date: |
Sat, 6 Oct 2018 21:42:16 -0400 |
User-agent: |
Mutt/1.9.4 (2018-02-28) |
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.
- [Qemu-devel] [RFC PATCH 00/21] Trace updates and plugin RFC, Alex Bennée, 2018/10/05
- [Qemu-devel] [RFC PATCH 04/21] trace: enable the exec_tb trace events, Alex Bennée, 2018/10/05
- [Qemu-devel] [RFC PATCH 01/21] util/log: allow -dfilter to stack, Alex Bennée, 2018/10/05
- [Qemu-devel] [RFC PATCH 05/21] trace: keep a count of trace-point hits, Alex Bennée, 2018/10/05
- [Qemu-devel] [RFC PATCH 18/21] linux-user: allow dumping of plugin status at end of run, Alex Bennée, 2018/10/05
- [Qemu-devel] [RFC PATCH 10/21] qom/cpu: add a cpu_exit trace event, Alex Bennée, 2018/10/05
- [Qemu-devel] [RFC PATCH 12/21] configure: expose a plugin to the trace-backends, Alex Bennée, 2018/10/05