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Date: Mon, 3 Aug 2009 02:08:14 +0000
Message-ID: <9ae48b020908021908v123aa866g470b78477f369594@mail.gmail.com>
Subject: Re: [Qemu-devel] [PATCH] slirp: Read host DNS config on demand
From: Ed Swierk <eswierk@aristanetworks.com>
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To: Jan Kiszka <jan.kiszka@web.de>, "Michael S. Tsirkin" <mst@redhat.com>, qemu-devel@nongnu.org

On Sun, Aug 2, 2009 at 8:03 AM, Jan Kiszka<jan.kiszka@web.de> wrote:
> IMHO, 10 s is below the user surprise threshold for a dynamically
> changing network link. Moreover, inotify does not exist on all platforms.
>
> Let's keep things simple for the first step, we could still further
> improve it later on. 10 s are already an improvement over the current
> infinite timeout.

Right. The most common situation in which the DNS server address
changes is after you wake up your laptop and wait for it to connect to
a new network. DHCP itself can take several seconds to do its thing,
so you're unlikely to notice the up-to-10-second delay before full
network connectivity is restored in a VM.

Of course there's nothing magical about 10 seconds. A shorter timeout
would be even nicer, and I doubt anyone would really miss the CPU
cycles lost to re-reading a tiny text file, but I don't think
instantaneous response is required here.

--Ed