Hi All,
I am new to Xen, and would like to know if anyone can help with this problem
I have.
I have a dual - Quad Core Intel 5535 VT 2.66 server, with 24G ram running
CentOS5 dom0 and domU (both 64 bit). Everything works great and I am VERY
impressed with the efficiency of Xen (i have always been a UML man). I would
however, like to run a single domU domain, with a single VCPU, but get the
power of say, 7 cores, leaving 1 to the dom0 instance. First off, I would
like to know if this is possible.
In my config file I have specified cpus = "1-7" and vpus=1 in the hope
that
the 1 vcpu would be an almighty powerful one, but this isn''t the case.
There
is no errors booting it up, and
[\047cpus\047, \0470-7\047]
appears in the xend logfile.
Here is a copy of the config file.
name = "test1"
builder = "hvm"
memory = "20000"
disk = [ ''file:/virtual/test1,hda,w'', ]
vif = [ ''type=ioemu, mac=00:16:3e:18:34:76, bridge=xenbr0'', ]
uuid = "d8a2a092-399a-ecb9-24fb-7caf66f883b2"
device_model = "/usr/lib64/xen/bin/qemu-dm"
kernel = "/usr/lib/xen/boot/hvmloader"
vnc=0
# vncunused=1
apic=1
acpi=1
pae=1
cpus="0-7"
vcpus=1
usb=0
serial = "pty" # enable serial console
on_reboot = ''restart''
on_crash = ''restart''
Any help / advice / comments and greatly appreciated.
Regards, Matt Hanna
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Hello,> I would > however, like to run a single domU domain, with a single VCPU, but get the > power of say, 7 cores, leaving 1 to the dom0 instance. First off, I would > like to know if this is possible. >No it''s imppossible : multiples cpus means parallelization, so the scheduler of the guest OS has to be aware of each cpus. 1 vcpu = 1 hardware thread.> In my config file I have specified cpus = "1-7" and vpus=1 in the hope > that > the 1 vcpu would be an almighty powerful one, but this isn''t the case.This mean that your vcpus can use one of the 1-7 cpus, and not the 0 one. But only one at a time. Mehdi _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
On Tue, Oct 02, 2007 at 04:49:17PM -0700, matthewh wrote:> > I have a dual - Quad Core Intel 5535 VT 2.66 server, with 24G ram running > CentOS5 dom0 and domU (both 64 bit). Everything works great and I am VERY > impressed with the efficiency of Xen (i have always been a UML man). I would > however, like to run a single domU domain, with a single VCPU, but get the > power of say, 7 cores, leaving 1 to the dom0 instance. First off, I would > like to know if this is possible.If this would work it could be the answer to all scaling problems, just add cores together and present this as one to the domU. Cant work if you imagine that there get instructions computed on multiple cores simultaneously, you cant ''shuffle those instructions around to present it as one fast core'' to the domU.> cpus="0-7""the domU can run on the physical cores numbered 0-7"> vcpus=1"present one logical core to the domU" is what you are saying in the config. Christian _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users
You can''t combine CPUs to make a more powerful virtual CPU, sadly. However, there are a flexible set of parametrs that you can use to portion power: you can dedicate whole cores to a domU, you can allow it to run only on certain cores, you can allow it to run share some cores with other domains, you can specify the aggregate power it gets (in terms of % of one CPU) per unit time. Hopefully this will help get you where you want to go. If there''s something specific you want to achieve, maybe you could explain it to the list and somebody might have helpful ideas / comments. Cheers, Mark On Wednesday 03 October 2007, matthewh wrote:> Hi All, > > I am new to Xen, and would like to know if anyone can help with this > problem I have. > > I have a dual - Quad Core Intel 5535 VT 2.66 server, with 24G ram running > CentOS5 dom0 and domU (both 64 bit). Everything works great and I am VERY > impressed with the efficiency of Xen (i have always been a UML man). I > would however, like to run a single domU domain, with a single VCPU, but > get the power of say, 7 cores, leaving 1 to the dom0 instance. First off, I > would like to know if this is possible. > > In my config file I have specified cpus = "1-7" and vpus=1 in the hope that > the 1 vcpu would be an almighty powerful one, but this isn''t the case. > There is no errors booting it up, and > [\047cpus\047, \0470-7\047] > appears in the xend logfile. > > Here is a copy of the config file. > > name = "test1" > builder = "hvm" > memory = "20000" > disk = [ ''file:/virtual/test1,hda,w'', ] > vif = [ ''type=ioemu, mac=00:16:3e:18:34:76, bridge=xenbr0'', ] > uuid = "d8a2a092-399a-ecb9-24fb-7caf66f883b2" > device_model = "/usr/lib64/xen/bin/qemu-dm" > kernel = "/usr/lib/xen/boot/hvmloader" > vnc=0 > # vncunused=1 > apic=1 > acpi=1 > pae=1 > cpus="0-7" > vcpus=1 > usb=0 > serial = "pty" # enable serial console > on_reboot = ''restart'' > on_crash = ''restart'' > > Any help / advice / comments and greatly appreciated. > > Regards, Matt Hanna-- Dave: Just a question. What use is a unicyle with no seat? And no pedals! Mark: To answer a question with a question: What use is a skateboard? Dave: Skateboards have wheels. Mark: My wheel has a wheel! _______________________________________________ Xen-users mailing list Xen-users@lists.xensource.com http://lists.xensource.com/xen-users