Ron Johnson wrote: > On 12/22/08 09:13, Eugene V. Lyubimkin wrote: >> Thomas Preud'homme wrote: >>> The Monday 22 December 2008 13:53:43 Eugene V. Lyubimkin, you wrote : >>>> Volkan YAZICI wrote: >>>>> Hi, >>>>> >>>>> Are there any compression tools in the official Debian GNU/Linux >>>>> repositories that can take the benefit of multiple cores/cpus? >>>> pbzip2? >>> >>> I profit of this thread to ask you if you see amelioration with >>> pbzip2. I made 2 tests on file of 50 MB and the result if >>> approximately the same time as bzip2 (a little much longer with >>> pbzip2 !!!) but a CPU twice time more used. I have a core 2 duo and >>> time give me a usage of almost 200% with pbzip2 >>> >>> Anyone has better results ? >> Yes, see following: >> >> jackyf@work:~/temp$ time tar -cjf temp1.tar.bz2 debian >> >> real 0m18.830s >> user 0m18.317s >> sys 0m0.268s >> jackyf@work:~/temp$ time bash -c "tar -cf - debian | pbzip2 -c > >> temp2.tar.bz2" >> >> real 0m10.494s >> user 0m19.557s >> sys 0m0.488s >> >> 10 is much less than 18. > > That might be because much of the data is already cached. Each of those > commands should be run 3 times to get good numbers. We are not testing filesystem or disks, we testing CPU, and no even modern desktop CPUs can cache 36 MiB of data. But I retried these commands several times anyway to verify, and results are almost the same, maybe +/- 5%. -- Eugene V. Lyubimkin aka JackYF, JID: jackyf.devel(maildog)gmail.com Ukrainian C++ Developer, Debian Maintainer, APT contributor
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