Re: [PATCH 1/2] accel/tcg/plugin: export host insn size

[Alex Bennée]

Richard Henderson <richard.henderson@linaro.org> writes:

> On 4/6/23 00:46, Alex Bennée wrote:
>> If your aim is to examine JIT efficiency what is wrong with the current
>> "info jit" that you can access via the HMP? Also I'm wondering if its
>> time to remove the #ifdefs from CONFIG_PROFILER because I doubt the
>> extra data it collects is that expensive.
>> Richard, what do you think?
>
> What is it that you want from CONFIG_PROFILER that you can't get from perf?
> I've been tempted to remove CONFIG_PROFILER entirely.

I think perf is pretty good at getting the hot paths in the translator
and pretty much all of the timer related stuff in CONFIG_PROFILER could
be dropped. However some of the additional information about TCG ops
usage and distribution is useful. That said last time I had a tilt at
this on the back of a GSoC project:

  Subject: [PATCH  v9 00/13] TCG code quality tracking and perf integration
  Date: Mon,  7 Oct 2019 16:28:26 +0100
  Message-Id: <20191007152839.30804-1-alex.bennee@linaro.org>

The series ended up moving all the useful bits of CONFIG_PROFILER into
tb stats which was dynamically controlled on a per TB basis. Now that
the perf integration stuff was merged maybe there is a simpler series to
be picked out of the remains?

Fei Wu,

Have you looked at the above series? Is that gathering the sort of
things you need? Is this all in service of examining the translation
quality of hot code?

>
>
> r~


-- 
Alex Bennée
Virtualisation Tech Lead @ Linaro