Subject: Re: [PATCH] powerpc/configs: Enable function trace by default

From: Balbir Singh <[email-masked]>
Date: Thu, 13 Apr 2017 18:19:28 +1000

On Thu, 2017-04-13 at 09:24 +0200, Christophe LEROY wrote:
> Hi Baldir

Hi Christophe, It's Balbir

> 
> Le 13/04/2017 à 09:03, Balbir Singh a écrit :
> > We expect to have these configs on by default, most
> > distros turn them off, its always good to have them on
> > so that we can use them and hopefully not break them
> 
> Isn't it the purpose of the target allyesconfig to allow such tests ?
> 

As a developer I don't use allyesconfig for submitting patches or testing
the kernel.

> FTRACE is quite CPU consumming, shouldn't it really be on by default ?

It does some work at boot to NOP out function entry points at _mcount
locations. Is that what you are referring to? Or the overhead of the
code in terms of size? Most distro kernels have tracing on by default.

The rest of the overhead is enablement based.

Thanks for the review!
Balbir Singh