Date: Tue, 13 Mar 2001 07:59:43 +0200 From: Mark Murray <mark@grondar.za> To: Matt Dillon <dillon@earth.backplane.com> Cc: "David Schwartz" <davids@webmaster.com>, current@FreeBSD.ORG Subject: Re: Ethernet entropy harvesting seriously pessimizes performance Message-ID: <200103130558.f2D5wnf94700@gratis.grondar.za> In-Reply-To: <200103122231.f2CMVaL75959@earth.backplane.com> ; from Matt Dillon <dillon@earth.backplane.com> "Mon, 12 Mar 2001 14:31:36 PST." References: <200103122231.f2CMVaL75959@earth.backplane.com>
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> Let me be clear about what I mean by interrupt rate limiting: > > interrupt() > { > harvester(...) > } It does that already. > harvester(...) > { > if (queue is not full) { > ... add data to queue (reasonably sized queue, like 32 entries) > } > } It does that. I guess we differ on the idea of "reasonable". > queue-runner(...) > { > for(;;) { > sleep for 1/10 second > > Pull next item (if any) off queue > } > } It almost does that, except it sleeps every N items where the user is given control of N. > That is what my patch does. If a high rate of interrupts occur, the > queue becomes full almost instantly because the queue-runner only > pulls one item off per 1/10 second. The result is that the > harvester() routine effectively becomes a NOP for most of the > interrupts. My code does that. Do a "cat /dev/zero > /dev/random" to see it in action. 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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