[ kvm-Bugs-1998355 ] IO Performance

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Bugs item #1998355, was opened at 2008-06-20 00:11
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Category: None
Group: None
Status: Open
Resolution: None
Priority: 5
Private: No
Submitted By: Joshua Rosen (bjrosen)
Assigned to: Nobody/Anonymous (nobody)
Summary: IO Performance 

Initial Comment:
Is there any way of mapping a host's directory into a KVM VM similar to VMware's Shared Folder feature?

I've been benchmarking the performance of NCVerilog under various VMs. The performance of KVM when using a virtual disk is excellent, in fact it's better than VMware Server or VMware Workstation, however if you use
an NFS mounted host directory the performance is unspeakably awful. An NFS mounted directory under VMware Server 2.0 (Beta 2) is also slow but it's still significantly better than KVM. Using a Shared Folder with VMware Workstation eliminates the IO bottleneck, the performance there is about the same as accessing a virtual disk.

The system that I did these benchmarks on is a 3GHz Core2 with 8G of RAM. VMware was running under CentOS5.1 with a 2.6.23.7 kernel. KVM is running on Fedora 9 with a 2.6.25.xx kernel. The Verilog simulation times for my test suite are as follows,

Native				06:34
VM Server 2, virtual disk	08:05
VM Server 2, NFS		18:37
VM Workstation, shared folder	08:14
KVM, Virtual disk		07:42
KVM, NFS			38:36


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You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=893831&aid=1998355&group_id=180599