Date: Wed, 07 Mar 2001 16:38:40 +0200 From: Mark Murray <mark@grondar.za> To: Bruce Evans <bde@zeta.org.au> Cc: Maxim Sobolev <sobomax@FreeBSD.ORG>, dougb@FreeBSD.ORG, current@FreeBSD.ORG Subject: Re: harvest_interrupt=YES slows down machine Message-ID: <200103071437.f27EbmR59707@gratis.grondar.za> In-Reply-To: <Pine.BSF.4.21.0103080020001.2722-100000@besplex.bde.org> ; from Bruce Evans <bde@zeta.org.au> "Thu, 08 Mar 2001 00:42:39 %2B1100." References: <Pine.BSF.4.21.0103080020001.2722-100000@besplex.bde.org>
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> Just do something that causes a lot of interrupts that go through the > random harvester. E.g.: > > dd if=/dev/ad0 of=/dev/null > > causes 7750 interrupts/sec here (on a Celeron 366 overclocked to > 522). The random task takes 100% of the available cpu cycles. This > slows down cpu-bound processes by a factor of about 3.5. With a block > size of 64k instead of the default of 512, this causes only 300 > interrupts/sec. The random task takes a measly 27% of the cpu to > process these. It can apparently only handle about 10 interrupts/second > with a reasonable overhead (1%). OK. Try tweaking the "Computational intensity factor" ;-) by dropping the kern.random.yarrow.bins: # sysctl -w kern.random.yarrow.bins=2 And let me know how well that works. M -- Mark Murray Warning: this .sig is umop ap!sdn To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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