[OE-core] Results for xz compression with different -T and and -e

[Khem Raj]

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

if we have to use a default it should be -T0 IMO since everyone dont
have same number of CPUs

> regards,
>
> koen
>
>
>>
>> @g
>
> _______________________________________________
> Openembedded-core mailing list
> Openembedded-core at lists.openembedded.org
> http://lists.linuxtogo.org/cgi-bin/mailman/listinfo/openembedded-core