xcp-ng CPU low performance issue
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@tuxen said in xcp-ng CPU low performance issue:
xenpm start 1 | grep -i "avg freq"
[06:13 xcp-ng-lmtguftk ~]# xenpm start 1 | grep -i "avg freq"
Avg freq 64 KHz
Avg freq 64 KHz
Avg freq 64 KHz
Avg freq 64 KHz
Avg freq 64 KHz
Avg freq 64 KHz
Avg freq 64 KHz
Avg freq 64 KHz
Avg freq 64 KHz
Avg freq 64 KHz
Avg freq 64 KHz
Avg freq 64 KHz -
ll performance settings in the server bios settings are as follows.
System Profile Current Value Pending Value
CPU Power Management System DBPM (DAPC)
Memory Frequency Maximum Performance
Turbo Boost Enabled
C1E Enabled
C States Enabled
Write Data CRC Disabled
Memory Patrol Scrub Standard
Memory Refresh Rate 1x
Uncore Frequency Dynamic
Energy Efficient Policy Balanced Performance
Number of Turbo Boost Enabled Cores for Processor 1 All
Number of Turbo Boost Enabled Cores for Processor 2 All
Monitor/Mwait Enabled
Workload Profile Not Available
CPU Interconnect Bus Link Power Management Enabled
PCI ASPM L1 Link Power Management EnabledCPU Power Management Some options include = Performans Per Watt (OS ), Performans Per Watt (DAPC ), Performance, Workstation Performans, Custom
Workload Profile Some options include = HPC Profile =,Low Latency Optimized Prodile, Virtualization Optimized Performans Profile, Virtualization Optimized Performans Per Watt Profile, Database Optimized Performans Profile, Database Optimized Performans Per Watt Profile, SDS Optimized Performans Profile and SDS Optimized Performans Per Watt Profile
I have tried the above options one by one but the result has not changed. -
The incorrect clock results mean that Xen isn't in charge of frequency scaling management. Set the CPU Power Management to
Performance Per Watt (OS)and run the previousxenpm, this time with awatchfor real-time:# watch 'xenpm start 1 | grep -i "avg freq"'Start a VM boot storm (or a stress test inside one or more VMs) in order to generate some CPU load.
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This is one of our production servers with the CPU Power Management config I posted earlier. It's a Dell R730 - Xeon E5-2630v3 @ 2.40 Ghz. As you can see, some cores are boosting to
3.0-3.1GHz. The maximum for this CPU model is 3.2 GHz:Avg freq 2737140 KHz Avg freq 2737140 KHz Avg freq 2689120 KHz Avg freq 2665110 KHz Avg freq 2737140 KHz Avg freq 3097290 KHz Avg freq 3073280 KHz Avg freq 2713130 KHz Avg freq 2665110 KHz Avg freq 2641100 KHz Avg freq 2761150 KHz Avg freq 2665110 KHz Avg freq 2689120 KHz Avg freq 2617090 KHz Avg freq 2881200 KHz Avg freq 2785160 KHz Avg freq 2641100 KHz Avg freq 2713130 KHz Avg freq 2689120 KHz Avg freq 2689120 KHz Avg freq 2689120 KHz Avg freq 2785160 KHz Avg freq 2833180 KHz Avg freq 2761150 KHz Avg freq 2761150 KHz Avg freq 2905210 KHz Avg freq 2713130 KHz Avg freq 3025260 KHz Avg freq 2761150 KHz Avg freq 2713130 KHz Avg freq 2833180 KHz Avg freq 2617090 KHz -
@tuxen said in xcp-ng CPU low performance issue:
Start a VM boot storm (or a stress test inside one or more VMs) in order to generate some CPU load.
Thank you very much for your information. I tried and saw the following results in real time.Every 2,0s: xenpm start 1 | grep -i "avg freq" Thu Nov 28 13:27:00 2019
Avg freq 2521200 KHz
Avg freq 2689280 KHz
Avg freq 2836350 KHz
Avg freq 2689280 KHz
Avg freq 2731300 KHz
Avg freq 2689280 KHz
Avg freq 2773320 KHz
Avg freq 2752310 KHz
Avg freq 2689280 KHz
Avg freq 2689280 KHz
Avg freq 2710290 KHz
Avg freq 2710290 KHz
Avg freq 2689280 KHz
Avg freq 2710290 KHz -
Try to disable C-States, it could also improve a lot of operations, including storage.
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@ruskofd I turned off the C1E and C States features. Problem is solved. But SSD performance is very low compared to windows machine.
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bumping this as it is relevant for my datacenter. Don't want to forget it!
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Feel free to submit a PR in our official doc, we might have a place for "Best practice" or something like that
