Hi,
When I run some workloads from SPECCPU2006. I found that the retired
instruction number vary significantly between VM and PM according to
xenoprof. For example:
Workload Insts
Platform
435.gromacs (CPU intensive) 4458151
PM
435.gromacs * 151265683*
VM
450.soplex (Memory intensive) 760142
PM
450.soplex * 23311208*
VM
What is the reason? Does Xen use interpret? Thank you!
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On Tue, May 22, 2012 at 7:51 AM, suixiufeng <suixiufeng@gmail.com> wrote:> Hi, > When I run some workloads from SPECCPU2006. I found that the retired > instruction number vary significantly between VM and PM according to > xenoprof. For example: > > Workload Insts > Platform > 435.gromacs (CPU intensive) 4458151 > PM > 435.gromacs 151265683 > VM > 450.soplex (Memory intensive) 760142 > PM > 450.soplex 23311208 > VM > > What is the reason? Does Xen use interpret? Thank you!I take you to mean, "Does Xen emulate guest instructions"? The answer is "No", with one exception: for HVM guests, Xen will emulate accesses to devices, including MMIO and PIO. There''s not really enough information here to even make a guess as to what might be causing your numbers here; it''s not even really clear what the numbers you''re reporting are, as they seem to be instructions rather than the performance. If you could give a bit more information about what kind of guest OS you''re running, your setup, how you''re collecting data, and what it means, we might be able to be more helpful. -George
---------- Forwarded message ---------- From: suixiufeng <suixiufeng@gmail.com> Date: 2012/5/22 Subject: Re: [Xen-devel] Benchmark in the VM To: George Dunlap <George.Dunlap@eu.citrix.com> The dom0 kernel is centos5.5, and the Hypervisor is xen-4.1.2. The domU kernel is centos5.5, which is installed through the virt-install command (I think it belongs to HVM). Then I use xenoprof to collect the cycle, instruction number, LLC access number and LLC miss number information when running spec cpu 2006 benchmarks. And I found the instruction number increased significantly as shown in my last email. I don''t know what''s the reason. 2012/5/22 George Dunlap <George.Dunlap@eu.citrix.com>> On Tue, May 22, 2012 at 7:51 AM, suixiufeng <suixiufeng@gmail.com> wrote: > > Hi, > > When I run some workloads from SPECCPU2006. I found that the retired > > instruction number vary significantly between VM and PM according to > > xenoprof. For example: > > > > Workload Insts > > Platform > > 435.gromacs (CPU intensive) 4458151 > > PM > > 435.gromacs 151265683 > > VM > > 450.soplex (Memory intensive) 760142 > > PM > > 450.soplex 23311208 > > VM > > > > What is the reason? Does Xen use interpret? Thank you! > > I take you to mean, "Does Xen emulate guest instructions"? The answer > is "No", with one exception: for HVM guests, Xen will emulate accesses > to devices, including MMIO and PIO. > > There''s not really enough information here to even make a guess as to > what might be causing your numbers here; it''s not even really clear > what the numbers you''re reporting are, as they seem to be instructions > rather than the performance. If you could give a bit more information > about what kind of guest OS you''re running, your setup, how you''re > collecting data, and what it means, we might be able to be more > helpful. > > -George >_______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
On Wed, May 23, 2012 at 2:13 AM, suixiufeng <suixiufeng@gmail.com> wrote:> Then I use xenoprof to collect the cycle, instruction number, LLC access > number and LLC miss number information when running spec cpu 2006 > benchmarks.Just to be clear: "PM" means you''re not running with Xen at all? (In which case the numbers were collected using oprofile, not xenoprof)? Or do you mean you''re comparing running it in a dom0 to a domU? (Also, just FYI: the standard on the xen-devel list is to reply in-line, or at the bottom, rather than top-posting.) -George