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Re: [Xen-devel] VT is comically slow

To: xen-devel@xxxxxxxxxxxxxxxxxxx
Subject: Re: [Xen-devel] VT is comically slow
From: alex@xxxxxxxxxxxxxxx
Date: Thu, 06 Jul 2006 11:16:18 -0800
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Rik van Riel wrote:
> VT by itself seems fine, but once a VT domain is running a workload that
> is network intensive combined with a disk/cpu intensive workload, things
> get incredibly slow.
> Operations that take less than a second with either workload running
> alone can now take many seconds, sometimes the better part of a minute!
> Is this some limitation of the qemu device model?

We (Virtual Iron) are in a process of developing accelerated drivers for the 
HVM guests.  Our goal for this effort is to get as close to native performance 
as possible and to make paravirtualization of guests unnecessary.  The drivers 
currently support most flavors of RHEL, SLES and Windows.  The early 
performance numbers are encouraging.  Some numbers are many times faster than 
QEMU emulation and are close to native performance numbers (and we are just 
beginning to tune the performance).

Just to give people a flavor of the performance that we are getting, here are 
some preliminary results on Intel Woodcrest (51xx series), with a Gigabit 
network, with SAN storage and all of the VMs were 1 CPU.  These numbers are 
very early, disks numbers are very good and we are still tuning the network 

Bonnie-SAN - bigger is better        RHEL-4.0 (32-bit)   VI-accel 
Write, KB/sec                          52,106                 49,500
Read, KB/sec                           59,392                 57,186 

netperf - bigger is better           RHEL-4.0 (32-bit)   VI-accel 
tcp req/resp (t/sec)                   6,831                  5,648

SPECjbb2000 - bigger is better       RHEL-4.0 (32-bit)   VI-accel 
JRockit JVM thruput                    43,061                 40,364

This code is modeled on Xen backend/frontend architecture concepts and will be 
-Alex V.

Alex Vasilevsky
Chief Technology Officer, Founder
Virtual Iron Software, Inc

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