Subject: Re: Difficulties for compilation without extra optimisation
To: Steven Rostedt <rostedt@goodmis.org>, kernel-janitors@vger.kernel.org
Cc: linux-kselftest@vger.kernel.org, linux-nfs@vger.kernel.org,
        linux-kernel@vger.kernel.org, Peter Zijlstra <peterz@infradead.org>,
        Trond Myklebust <trondmy@primarydata.com>
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 <1512314250.3673.6.camel@primarydata.com>
 <20171203162256.4ea0750d@vmware.local.home>
From: SF Markus Elfring <elfring@users.sourceforge.net>
Message-ID: <bd57d7d5-c8f5-0bc9-c96f-37550557dca3@users.sourceforge.net>
Date: Sun, 3 Dec 2017 22:56:51 +0100
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> Why would you compile the kernel without optimization?

I would like to see how big an effect finally is in such a build configuration
after specific source code adjustments.


> There's many places in the kernel that WILL NOT BUILD without optimization.

I did not really know this detail so far.

I noticed that the optimised build variants worked during my test comparisons.


> 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.

Thanks for your information.

Can the software areas distinguished where such special handling matters?

Regards,
Markus