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From: Fabian Deutsch <fabian.deutsch@gmx.de>
To: kvm@vger.kernel.org
Subject: massive performance drop after a while when using virtio nics
Date: Sat, 23 Aug 2008 21:21:56 +0200	[thread overview]
Message-ID: <1219519317.2909.12.camel@decade.local> (raw)

Hey.

When running a guest in the following setup, I observ a "massive"
performance decrease after a couple of gigabytes of transfrerred data.

other guests keep running fine (no regressions) and nothing unusual is
observed on the host.

fedora 8 host, kvm-72 (user and module)

fedora 9 guest, all updates.
        nic 0, vtio:
        subnet a
        samba listening

        nic 1, vtio:
        subnet b
        iscsi initiator running

        samba shares a mount point, pointing to an iscsi target.


now pulling/pushing about 80GB over samba results in a drop from about
60/70Mbit to about 1/2Mbit of troughput.

The problem is reproducible.
The problem is solved after a reboot of the guest. Just restarting
networking doesn't help.
Guest's dmesg doesn't say anything about problems. No errors in
ifconfig.

Has someone observed something similar?


Greetings
- fabian


             reply	other threads:[~2008-08-23 19:22 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-08-23 19:21 Fabian Deutsch [this message]
2008-09-08 12:07 ` massive performance drop after a while when using virtio nics Yann Dupont
2008-09-08 13:16   ` Fabian Deutsch
2008-09-08 13:33     ` Yann Dupont
2008-09-09 10:22 ` Mark McLoughlin
2008-09-09 10:32   ` Fabian Deutsch
2008-09-09 10:47     ` Mark McLoughlin
2008-09-09 11:11       ` Henrik Holst
2008-09-09 11:41         ` Mark McLoughlin
2008-09-09 11:54   ` Yann Dupont

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