Messages in this thread | | | Subject | Re: Strange IDE performance change in 2.6.1-rc1 (again) | From | Valdis.Kletnieks@vt ... | Date | Fri, 02 Jan 2004 23:15:18 -0500 |
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On Sat, 03 Jan 2004 04:33:28 +0100, Tobias Diedrich <ranma@gmx.at> said:
> Very interesting tidbit: > > with 2.6.1-rc1 and "dd if=/dev/hda of=/dev/null" I get stable 28 MB/s, > but with "cat < /dev/hda > /dev/null" I get 48 MB/s according to "vmstat > 5".
'cat' is probably doing a stat() on stdout and seeing it's connected to /dev/null and not even bothering to do the write() call. I've seen similar behavior in other GNU utilities. [unhandled content-type:application/pgp-signature] | |