<div class="gmail_quote">On Thu, Jul 12, 2012 at 6:40 PM, Koen Kooi <span dir="ltr"><<a href="mailto:koen@dominion.thruhere.net" target="_blank">koen@dominion.thruhere.net</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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Op 12 jul. 2012 om 17:29 heeft Andrei Gherzan <<a href="mailto:andrei@gherzan.ro">andrei@gherzan.ro</a>> het volgende geschreven:<br>
<div><div class="h5"><br>
> Hello,<br>
><br>
> Koen suggested to add -T to xz commands. We have this option implemented in our current version .1alpha.<br>
><br>
> -T threads, --threads=threads<br>
> Specify the number of worker threads to use. Setting threads to<br>
> a special value 0 makes xz use as many threads as there are CPU<br>
> cores on the system. The actual number of threads can be less<br>
> than threads if the input file is not big enough for threading<br>
> with the given settings or if using more threads would exceed<br>
> the memory usage limit.<br>
><br>
> -------------------<br>
><br>
> Memory: 7.8 GiB<br>
> Processor:: Intel® Core™ i5-2540M CPU @ 2.60GHz × 4<br>
><br>
> File to compress: 1.9G<br>
><br>
> xz -f -k -e -9 --check=crc32 (current configuration)<br>
> Memory: 673Mb<br>
> real 6m37.170s<br>
> user 6m35.389s<br>
> sys 0m0.884s<br>
> Compressed file size: 3.4Mb<br>
><br>
> xz -f -k -e -9 -T 4 --check=crc32<br>
> Memory: Cannot allocate memory<br>
><br>
> xz -f -k -e -8 -T 4 --check=crc32<br>
> Memory: 1.8G<br>
> real 3m24.462s<br>
> user 12m8.502s<br>
> sys 0m2.180s<br>
> Compressed file size: 3.4Mb<br>
><br>
> xz -f -k -T 4 --check=crc32 (-e defaults to -6)<br>
> Memory: 471Mb<br>
> real 1m9.265s<br>
> user 4m8.972s<br>
> sys 0m0.944s<br>
> Compressed file size: 3.4Mb<br>
><br>
> So my conclusion would be to use the default -e -6 with -T 4.<br>
<br>
</div></div>Out of curiousity, what does -T0 give you?<br><br></blockquote><div> </div><div>Exactly the same as -T 0. </div><div><br></div><div>@g</div></div><br>