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Date: Fri, 10 Mar 2017 08:20:56 +0100
From: Ingo Molnar <mingo@kernel.org>
To: Andy Lutomirski <luto@amacapital.net>
Cc: Steven Rostedt <rostedt@goodmis.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Thomas Gleixner <tglx@linutronix.de>, "H. Peter Anvin" <hpa@zytor.com>,
        Andy Lutomirski <luto@kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH 1/2] x86/nmi: Optimize the check for being in the
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* Andy Lutomirski <luto@amacapital.net> wrote:

> > It had nothing to do with speedup. Linus said that the current code makes the 
> > assembly programmer in him die a little. I want to cure that.
> 
> One might argue that the world would be a better place if the assembly 
> programmer in some people died a little.

Joking aside, I'll bite: while in the kernel we try to avoid ever actually 
_writing_ new assembly code, assembly programming is still an invaluable skill, 
because it indirectly improves all the other 99% of non-assembly .c code:

 - Looking at the C compiler's assembly output tells us how close the code is to
   optimal.

 - Being able to tell whether our C abstractions are too far removed from how the
   compiler will map it to machine instructions is invaluable.

 - Being able to shape data structures and code in a machine-friendly way.

Much would be lost if the assembly programmer went extinct and it's no 
accident that annotated assembly output is just two <Enter> keys away
after launching 'perf top' or 'perf report'. The more developers know
assembly the better, IMHO.

Thanks,

	Ingo