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Groups > comp.os.linux.misc > #16970
| From | Robert Riches <spamtrap42@jacob21819.net> |
|---|---|
| Newsgroups | comp.os.linux.misc |
| Subject | Re: seq command terribly slow |
| Date | 2016-03-13 16:42 +0000 |
| Organization | none-at-all |
| Message-ID | <slrnneb63g.p81.spamtrap42@one.localnet> (permalink) |
| References | <slrnne9qgo.5pk.spamtrap42@one.localnet> <874mca36r7.fsf@mantic.terraraq.uk> |
On 2016-03-13, Richard Kettlewell <rjk@greenend.org.uk> wrote: > Robert Riches <spamtrap42@jacob21819.net> writes: >> Any ideas why the seq command is so terribly slow? >> >> In order to test whether a new (well, used, but that's another >> story) disk, I tried using seq to generate a non-repeating >> pattern. After seeing seq consuming 100% CPU time and a very low >> data rate being written to disk, I did some checking on a >> few-years-old system with a Xeon W3680 running Debian 7/Wheezy. >> >> This command shows about 15MB/s: >> >> seq 1e12 | pv > /dev/null >> >> This command shows about 600MB/s, ~40X faster with much lower >> total CPU use: >> >> yes '' | cat -n | tr -d ' \t' | head -c 1000000000000 | pv > /dev/null > > I see near-reverse behaviour in jessie (on a Q6600). seq yields more > than 500MB/s while the pipeline is below 300MB/s. > > Perhaps seq has been improved since the version in wheezy. Good to hear it has apparently improved. That would make it much more useful. I plan to switch to a different distribution soon due to Wheezy's age, so I'll look forward to confirming that improvement. Thanks. -- Robert Riches spamtrap42@jacob21819.net (Yes, that is one of my email addresses.)
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seq command terribly slow Robert Riches <spamtrap42@jacob21819.net> - 2016-03-13 04:18 +0000
Re: seq command terribly slow Richard Kettlewell <rjk@greenend.org.uk> - 2016-03-13 12:24 +0000
Re: seq command terribly slow Robert Riches <spamtrap42@jacob21819.net> - 2016-03-13 16:42 +0000
Re: seq command terribly slow "Anonymous Remailer (austria)" <mixmaster@remailer.privacy.at> - 2016-03-14 14:22 +0100
Re: seq command terribly slow Robert Riches <spamtrap42@jacob21819.net> - 2016-03-15 02:38 +0000
Re: seq command terribly slow Gernot Fink <g.fink@gmx.net> - 2016-03-13 18:21 +0100
Re: seq command terribly slow Richard Kettlewell <rjk@greenend.org.uk> - 2016-03-13 17:45 +0000
Re: seq command terribly slow Eli the Bearded <*@eli.users.panix.com> - 2016-03-14 21:58 +0000
Re: seq command terribly slow Robert Riches <spamtrap42@jacob21819.net> - 2016-03-15 02:44 +0000
Re: seq command terribly slow Eli the Bearded <*@eli.users.panix.com> - 2016-03-16 00:41 +0000
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