Re: Difficulties for compilation without extra optimisation
From: SF Markus Elfring
Date: Mon Dec 04 2017 - 05:19:49 EST
>> Will the compilation be a bit quicker when extra data processing
>> could be omitted?
>
> Why would you care more about the time it takes to compile the kernel,
> than the time it takes for executing it?
I am also interested in the evolution of compilation time frames.
> Benchmarks are all about performance of a running kernel,
This is generally reasonable.
> nobody compares benchmarks of the time it takes to compile it.
I guess that the situation can be occasionally different there.
> Sure, we like to make the compile times quicker
Good to know â
> (heck, I wrote "make localmodconfig" for just that purpose),
Thanks.
> but we never favor compiler time over execution time.
I imagine that the speed expectations could be adjusted during software development,
couldn't they?
> In fact, if we can improve the execution performance by sacrificing compile time,
> we are happy to do that.
I guess that you would like to consider some constraints there.
>>> In fact, we do a lot of tricks to make sure that things work the way
>>> we expect it to, because we add broken code that only gets compiled out
>>> when gcc optimizes the code the way we expect it to be,
>>> and the kernel build will break otherwise.
>>
>> * Can this goal be also achieved without the addition of âbroken codeâ?
>
> No.
Will any other contributors take another look?
>> * How do you think about to improve the error handling there?
>
> It works just fine as is.
I hope that further software improvements can be achieved also for this use case.
> Errors that can be detected at build time are 100 times better
> than detecting them at execution time.
I agree to such a general view.
Will an other (or no) error message be more appropriate?
Regards,
Markus