From mboxrd@z Thu Jan  1 00:00:00 1970
From: Rusty Russell <rusty@rustcorp.com.au>
Subject: Re: strange guest slowness after some time
Date: Wed, 8 Apr 2009 10:19:14 +0930
Message-ID: <200904081019.14768.rusty@rustcorp.com.au>
References: <49B29705.6000904@wpkg.org> <49D30801.5020201@wpkg.org> <49DA1D75.6000604@wpkg.org>
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Cc: "David S. Ahern" <daahern@cisco.com>,
	Felix Leimbach <felix.leimbach@gmx.net>, avi@redhat.com,
	kvm@vger.kernel.org, Anthony Liguori <anthony@codemonkey.ws>
To: Tomasz Chmielewski <mangoo@wpkg.org>
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	Tue, 7 Apr 2009 20:49:20 -0400
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On Tuesday 07 April 2009 00:49:17 Tomasz Chmielewski wrote:
> Tomasz Chmielewski schrieb:
> 
> > As I mentioned, it was using virtio net.
> > 
> > Guests running with e1000 (and virtio_blk) don't have this problem.
> 
> Also, virtio_console seem to be affected by this "slowness" issue.

I'm pretty sure this is different.  Older virtio_console code ignored
interrupts and polled, and use a heuristic to back off on polling (this was
because we used the generic "hvc" infrastructure which hacked support).

You'll find a delay on the first keystroke after idle, but none on the
second.

Hope that helps,
Rusty.