Date: Tue, 20 Jul 2004 09:32:08 -0400 (EDT) From: Robert Watson <rwatson@freebsd.org> To: Scott Long <scottl@samsco.org> Cc: freebsd-current@freebsd.org Subject: Re: I/O or Threading Suffer Message-ID: <Pine.NEB.3.96L.1040720093036.86342D-100000@fledge.watson.org> In-Reply-To: <40FD03E7.8000300@samsco.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
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