
Some Dynamic Measurements of Firefox on X86-64 - ingve
http://robert.ocallahan.org/2016/06/some-dynamic-measurements-of-firefox-on.html
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azinman2
Unrelated to content: anyone else (on mobile) find bloggers "gesture
detection" to go back/forward in the blog to be bloody annoying and never
desirable? I find as I scroll I often inadvertently am now on a different blog
post from that linked and then I'm having to fight it vs safari in navigating
history.

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cwzwarich
I find it odd that the GPRs r12/r13 are used more than r14/r15, because
they're both callee-save and the former have more restrictions on their use in
memory operands.

Also, the posts mentions video codecs, but if you're doing SW video decoding
then you've already failed at performance and power.

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cm3
Interesting analysis, but in what ways can we realistically affect the
instructions used without involving assembly?

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linkregister
Perhaps writing longer functions would cause the compiler to use more
registers, since it needs to keep track of more variables. Though I think this
is not the point.

I think the author was just pointing this out as an interesting exercise
rather than a call to action.

The hottest 5 instructions for the call to std::fill were generated by the
compiler that inexplicably didn't end up using a _rep_ (or variant)
instruction. But we don't know if in this case, fewer x86_64 instructions
profiles faster or slower.

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greglindahl
Compilers routinely inline code, even between source files. Programmers don't
need to stress about that.

And I don't think REP is ever the fastest, although it's sometimes the
shortest code.

