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terintamel
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Hypervisor - Too much CPU usage?

Fri Apr 26, 2019 2:05 am

I am wondering what is the expected CPU overhead for the Hypervisor? My ESXI host shows a CPU used % as around 67-70%. However my CHR VM in Winbox shows CPU usage of around 30%. Is it correct that the Hypervisor has around 40% overhead? That seems excessive.

My HW Specs
• CPU: LGA1151 socket for 7th Generation Intel® Core™ i7 processor
• Processor: Kaby Lake 7th Gen. i7-7700. Speed: 3.6GHz/8M
• Chipset: Intel® C236
• RAM: 32GB 2 x 16GB DDR4-2400
• SSD: 500GB mSata Samsung Evo
• Ethernet: Eight 10/100/1000 Auto MDI-X (4 bypass)
• Fiber: Two 1000 Auto SFP ports
• Fiber: Four 10G SFP+ ports
• Expansion: PCI-E 8x, MiniPCI slot
• USB: 2 x 3.0 ports on front
• Power: 1U redundant 280 W power supply (1+1)
• Operating System: VMware OSXi 6.5 (free edition) / MikroTik RouterOS CHR P10 (10Gig) as a VM

All NICs are running as VMXNET3.
 
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TomjNorthIdaho
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Re: Hypervisor - Too much CPU usage?

Fri Apr 26, 2019 7:48 pm

I am wondering what is the expected CPU overhead for the Hypervisor? My ESXI host shows a CPU used % as around 67-70%. However my CHR VM in Winbox shows CPU usage of around 30%. Is it correct that the Hypervisor has around 40% overhead? That seems excessive.

My HW Specs
• CPU: LGA1151 socket for 7th Generation Intel® Core™ i7 processor
• Processor: Kaby Lake 7th Gen. i7-7700. Speed: 3.6GHz/8M
• Chipset: Intel® C236
• RAM: 32GB 2 x 16GB DDR4-2400
• SSD: 500GB mSata Samsung Evo
• Ethernet: Eight 10/100/1000 Auto MDI-X (4 bypass)
• Fiber: Two 1000 Auto SFP ports
• Fiber: Four 10G SFP+ ports
• Expansion: PCI-E 8x, MiniPCI slot
• USB: 2 x 3.0 ports on front
• Power: 1U redundant 280 W power supply (1+1)
• Operating System: VMware OSXi 6.5 (free edition) / MikroTik RouterOS CHR P10 (10Gig) as a VM

All NICs are running as VMXNET3.
Is your VMware ESXi running other virtual servers at the same time? If so, you HyperVisor might be performing some swapping of resources.
If your HyperVisor is running multiple hosted systems, in VMware ESXi you have the ability to also configure the following:
- What cores are assigned to what virtual hosted systems. You want to avoid having any physical CPU cores swapping between different virtual hosted systems.
- In the BIOS for the physical machine and each virtual BIOS for each virtual machine , disable/remove all un-necessary devices (serial ports , parallel printer ports , CD-Drives .. ). Also disable all power management settings
- Use paravirtual drivers when possible for all virtual machines (network interfaces & SCSI controller selections)
- Consider using a Delayed-Ack setting of ( 1 )
- Disable hyper-threading
 
terintamel
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Posts: 47
Joined: Sun Sep 05, 2010 3:09 am

Re: Hypervisor - Too much CPU usage?

Sat Apr 27, 2019 3:20 am

No this ESXI host was purchased for just running one instance of CHR and nothing else.
Hyper-threading is disabled. NICs are Vmxnet3. Not sure about disk controller. Have not checked System or Virtual BIOS settings. As this is running as our Border router I will have to schedule downtime to check those.

Also as this was a preconfigured device I bought from BalticNetworks it already had the CHR created. However they setup the CHR to use 4 virtual cores, but the host only has 4 physical cores. Would I get better performance if I set the CHR to use 3 cores which would leave 1 core always open to the hypervisor than having the CHR use all 4 cores?
 
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TomjNorthIdaho
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Re: Hypervisor - Too much CPU usage?

Sat Apr 27, 2019 11:35 pm

No this ESXI host was purchased for just running one instance of CHR and nothing else.
Hyper-threading is disabled. NICs are Vmxnet3. Not sure about disk controller. Have not checked System or Virtual BIOS settings. As this is running as our Border router I will have to schedule downtime to check those.

Also as this was a preconfigured device I bought from BalticNetworks it already had the CHR created. However they setup the CHR to use 4 virtual cores, but the host only has 4 physical cores. Would I get better performance if I set the CHR to use 3 cores which would leave 1 core always open to the hypervisor than having the CHR use all 4 cores?
Not sure about what works best if you only have 4 cores.
However , FYI - something I recently read about … VMXNET-3 usage does use an additional CPU . You may want to read and check info about that.

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