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Re: [PATCH] ARM: Add optimized ARMv7 strcmp implementation

On Fri, Apr 25, 2014 at 4:11 AM, Richard Earnshaw <> wrote:
> These are the improvements for a production board with cortex-a15.  For
> very short strings there's a fair amount of noise in the measurements,
> but the regressions are generally very small, while the improvements can
> be significant. Yes, there are cases where the new code is more than
> three times faster.
> Length  1024    alignment       0/0:     238.38%
> Length  1024    alignment       0/0:     239.21%
> Length  1024    alignment       0/0:     247.45%

While for these cases it's clear from the surrounding context what
these numbers mean, I recommend not using percentages to describe
performance improvements. I'd be nice for glibc to adopt this policy
for sake of consistency and clarity.

If I saw in isolation

> Length  16      alignment       0/0:     105.97%

I wouldn't know whether this was measured relative to the original
performance (and was 5% faster) or as a speed up over the original
performance (and was a bit more than twice as fast).

This could be unambiguously written as

> Length  16      alignment       0/0:     2.0597x

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