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<div class="moz-cite-prefix">Just to add a tiny bit to the
conversation...<br>
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On 07/24/13 07:04, Renato Golin wrote:<br>
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<div dir="ltr">On 24 July 2013 02:08, Marcelo Sousa <span
dir="ltr"><<a moz-do-not-send="true"
href="mailto:marceloabsousa@gmail.com" target="_blank">marceloabsousa@gmail.com</a>></span>
wrote:<br>
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<div> - Vectorization can explode the amount of IR
beyond recognition</div>
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<div>Are you referring to vectorization as a
compiler transformation? Please elaborate and if
possible provide an example of this. Nevertheless,
I doubt that this happens in the particular case
of the Linux Kernel. </div>
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<div>Yes, and I agree, it's possible that the Kernel has
nothing worth vectorizing. It's just an example where your
tool wouldn't work at all.</div>
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In general the various cpu vector extensions and the FPU aren't used
in the kernel (though there are a few exceptions to this rule where
it makes sense). The overhead in always saving/restoring the state
of these parts of the CPU during system calls would be too high
(context switches between user and kernel space are many and already
relatively expensive). The FPU and vector extensions are saved for
use in userspace where they tend to have the most impact.<br>
<br>
Behan<br>
<pre class="moz-signature" cols="72">--
Behan Webster
<a class="moz-txt-link-abbreviated" href="mailto:behanw@converseincode.com">behanw@converseincode.com</a></pre>
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