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Date: Wed, 17 May 2017 13:33:41 +0300
From: Alexey Dobriyan <adobriyan@gmail.com>
To: joe@perches.com
Cc: akpm@linux-foundation.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] seq_file: delete small-value optimization
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> Joe Perches wrote:
> 
> On Tue, 2017-05-16 at 23:42 +0300, Alexey Dobriyan wrote:
> > num_to_str() optimizes printing small integers [0..9], so the same
> > check higher in callchain is unnecessary.
> 
> Doesn't the optimization exists for the frequent use of 0
> in seq output?  
> 
> These seq_put_decimal calls are now slightly more expensive.

That additional CALL instruction is hardly measurable so you're adding
branch to skip branch in the next function.