Date: Tue, 20 Jul 2004 15:53:02 +0200 From: "jesk" <jesk@killall.org> To: "Robert Watson" <rwatson@freebsd.org>, <freebsd-current@freebsd.org> Subject: Re: I/O or Threading Suffer Message-ID: <044201c46e60$dfdb1810$45fea8c0@turbofresse> References: <Pine.NEB.3.96L.1040720093036.86342D-100000@fledge.watson.org>
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> On Tue, 20 Jul 2004, Scott Long wrote: > > > If you are dd'ing from /dev/random, then you are depleting the entropy > > pool. Anything else that tries to get random numbers is going to block > > in strange ways. Trying just dd'ing from /dev/zero and see if that > > makes a difference. > > With Yarrow, /dev/random should just keep on chugging, so this is unlikely > to be the source. However, lots of /dev/random I/O may take a while to > yield if it's working hard in kernel, so if that is combined with a > scheduling nit of some sort, we could be looking at a starvation issue. > > Do we know if this is on a UP box or SMP box, and if so, whether it's > using HTT? I could try reproducing it here and see if I see the same > thing. > > Robert N M Watson FreeBSD Core Team, TrustedBSD Projects > robert@fledge.watson.org Principal Research Scientist, McAfee Research > > > > hi, i have tested it with /dev/zero, /dev/random and /dev/urandom, the same everywhere. as i mentioned i noticed the problem while mysqldump was dumping the mysqldatabase over night. in this timespan the mysqld didnt responsed to anything. after the dump(3minutes of time) the mysqld was back again and everything worked again. i have tested it with 2 UP boxes (i386/pIII) without HTT.
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