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Hyper-V Perf Problems?


Ncage1974
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1) Unless you're seeing significant slow downs on the bare metal (i.e. Server 2012) desktop, it ain't your CPU. It is more than powerful enough, and supports virtualization.

2) I sort of disagree with the more memory solution. Granted, more memory is (almost) always better, and for a Plex server it might help, but 4GB is more than enough to run a Chrome instance. 

3) Also don't agree with the dynamic memory solution. If the problem really is lack of memory, and adding more memory to the VM *does* help, then only use dynamic if you don't have enough physical to allocate. There are still timing issues with dynamic memory allocation, even when you reserve a significant percentage.

 

My guess - hard drive speed the VMs are located on.

 

The other part is the virtual graphics card (unless you are using RemoteFX) is just slow. Using RDP is going to show delays. Using the actual terminal services will be much more responsive, but if you want to get good results from Chrome (or any other recent browser that uses GPU acceleration as well as CPU) you'll need to enable RemoteFX.

 

Definitely not using RemoteFX unless its enabled by default and i didn't do anything to enable it. My video card in this machine isn't very powerful but, unless i'm mistaken, vmware doesn't have any technology similar to remotefx. I can tell you i have about the same setup locally on my more powerfully ivy bridge (i7-3770) and everything is smooth. I'm even using the same hard drive for the vm. The only difference is that i when i use RDP i'm RDPing locally rather than remotely but on my internal gigabit network it shouldn't make that much difference.

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Hey guys. Went home tonight and increased the vCPUs to 4. I also turned off dynamic memory & increased memory for the VM to 8GB. Fired up chrome and yep the problem is still there. Maybe it was a *little* faster but not much. To give you an idea i decided to take a screen shot (task manger in the vm itself). My hard drive are traditional 7200 rpm spinners. I shouldn't be putting that much load on them though. Got my new hardware from newegg today but don't know when i'll have time to install it. I'd still be nice to know what caused this before i put in the new hardware. I'm assuming the new hardware will make it go away. 

 

My apologies if I simply missed it in the thread -- what HD's are the VM's on?  Spinners? SSD's? RAID?

 

No reason to appoligize i took forever to respond back to the thread  :) . Just traditional 7200rpm spinners. No raid.


Oh i about forgot i tried to disable GPU accelerating in chrome hoping that would help but no dice.

badperf.PNG

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I have a Win8.1Pro64b running right now in a VM with 3 Win7VM's and a XP VM  all on the same VM drive but my VM drive is 4 VR's 6gen in RAID0 (see my tag line).  My Win8.1Enterprise isn't up right now (I need to fix some things on it)

 

My Win8.1 VM has 4 CPU's with 2GB base and Dynamic Memory enabled to go to the max as needed (allowing for a 20% memory buffer)

 

I keep my Snapshots, Smartpaging, VHDs, & VM's in different folders but all on the same VM drive.

 

Dumb question: you're using a separate network adapter for your VM's?

 

The i7-920 should be plenty power enough -- I've run a number of VM's on my desktop without any issues. Actually, I've run a number of VM's on my N40L without issues.  Could you check Task Manager and see which processes are chewing up your CPU cycles?

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I have a Win8.1Pro64b running right now in a VM with 3 Win7VM's and a XP VM  all on the same VM drive but my VM drive is 4 VR's 6gen in RAID0 (see my tag line).  My Win8.1Enterprise isn't up right now (I need to fix some things on it)

 

My Win8.1 VM has 4 CPU's with 2GB base and Dynamic Memory enabled to go to the max as needed (allowing for a 20% memory buffer)

 

I keep my Snapshots, Smartpaging, VHDs, & VM's in different folders but all on the same VM drive.

 

Dumb question: you're using a separate network adapter for your VM's?

 

The i7-920 should be plenty power enough -- I've run a number of VM's on my desktop without any issues. Actually, I've run a number of VM's on my N40L without issues.  Could you check Task Manager and see which processes are chewing up your CPU cycles?

 

Yep same thing i was thinking that the i7-920 should have plenty of juice for what i'm doing. I'm only running the server off of one intel gigabit nic

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Well just to add more to the unexplained i dug into the problem more. The host was previously running server core so i added the GUI elements back in to see if i could figure things out. Like you guys said i doubt its the cpu. When the cpu is pegged in the guest really don't see cpu go over 20% in the host. Its usually around 15-16%. The hardest thing hit seems to be the disk. For example when i tried to RDP in i seen the disk get hit pretty heavy (100% activity time with disk queue length up to 15). It did settle down after awhile though. When i ran chrome i could get the cpu to spike without overwhelming the disk and from the host's perspective everything looks ok. I'm sure if i dug into correctly monitoring perfmon counters & etw data for hyper-v i could figure out more info but unfortunately i doubt i'll have the time. I did notice the guest was running the microsoft stock video drivers and tried to upgrade to the OEM drivers to see if that would help but then again no dice. Its a ATI 3400 which should be just fine for a vm server. 

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Well i dug a little into perfmon counters. It seems like my last post was wrong. I thought the host would give you a good idea and it doesn't. You "have" to use perfmon to really see true cpu usage and of all the counters "% guest run time" is one of the most important. Here is me browsing with chrome and monitoring the counters:

 

perfmon.PNG

 

This i while i was doing "light" browsing with chrome. If interested here is a descent post on perfmon + hyper-v http://www.savision.com/resources/blog/will-real-cpu-usage-please-stand

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That's considerable CPU usage, but it's still not over 50% very much. Am I reading it right? OTOH, a disk cue length of 15 is, to my mind, huge. I've always heard anything over 4 needs to be addressed.

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I agree. Much like physical systems, the single biggest bottleneck in actual as well as perceived responsiveness for my VMs is hard drives. I suppose if memory were an issue that would of course be a problem, but with 32 GB of RAM over 5-6 VMs that hasn't been an issue. Moving my VMs to SSDs and/or a three drive RAID made huge improvements.

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