Re: [PATCH 10/10] perf, tools, stat: Output JSON MetricExpr metric

From: Andi Kleen
Date: Thu Feb 09 2017 - 12:15:47 EST

On Thu, Feb 09, 2017 at 12:39:37PM +0100, Jiri Olsa wrote:
> and this makes me think, that this is not the right approach
> adding extra copy of an event when you want to add new expression?

I don't want to add new expressions.

I don't even need arbitrary expressions, just DividedBy
to get percentages, you just forced me to do the expressions.

> why can't we have another list/file of those expressions

The last time I proposed separate files Ingo vetoed it.
He wanted everything built in.

> from which point we could point and configure events we need

If you want full flexibility you can use your perf stat report
approach, or what most people do is to just run a script/spreadsheet
over the the -x; output. This all continues to work.

This is just a minimum approach to provide some convenience
integrated with the event list to provide something similar
as the built in expressions in stat-shadow.

It's not trying to build the great perf scripting language.