Re: [PATCH v2 2/2] scripts: ftrace - move the nop-processing in ftrace_init to compile time

[Yinan Liu]

在 2021/11/16 下午4:10, Peter Zijlstra 写道:
> On Tue, Nov 16, 2021 at 10:49:42AM +0800, Yinan Liu wrote:
> > In some business scenarios, GCC versions are so old that
> > optimizations in ftrace cannot be completed, such as
> > -mrecord-mcount and -mnop-mcount. The recordmCount in the
> > kernel is actually used. In this case, ftrace_init will
> > consume a period of time, usually around 9~12ms. Do nop
> > substitution in recordmcount.c to speed up ftrace_init.
>
> I really don't buy this.. if you can build a fresh kernel, you can
> install a fresh gcc too -- and if you care about performance that's a
> very good idea anyway.
Thanks! You are right. We should get rid of the burden.