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jitla1971
Enthusiast
Enthusiast

CPU READY% & %CSTP

I need some clarification.

CPU READY - I have read 10% upper acceptable limit for cpu ready per cpu.

which is understandable

%CSTP should be less than 3% otherwise co-scheduler is having scheduling issues with vm's with multiple vcpu's.

This 3% is that per vcpu or total?

Below is a screenshot from ESXTOP i have highlighted 2 %CSTP figues.

Both these servers have multiple CPU's, so do i need to expand the vm and check %CSTP is less than 3% for each cpu or do i just look at the total like in the screenshot.

ESXTOP CTSP.JPG

Any clarification would be helpful.

Thanks

Jit

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memaad
Virtuoso
Virtuoso

Hi,

From  screen shot above, I see over commitment of vCPU on ESXI host.  Here is  link to esxtop quick reference which will answer your queries.

ESXTOP - Yellow Bricks

Regards

Mohammed

Mohammed | Mark it as helpful or correct if my suggestion is useful.
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jitla1971
Enthusiast
Enthusiast


thank you, yes there is over provision.

Hence why i want to know %CSTP 3% guideline, is that per vcpu or you just take the total, as seen in esxtop without expanding the world.

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memaad
Virtuoso
Virtuoso

Hi,

Its total,

%CSTP  : Excessive usage of vSMP. Decrease amount of vCPUs for this particular VM. This should lead to increased scheduling opportunities.

Regards

Mohammed

Mohammed | Mark it as helpful or correct if my suggestion is useful.
jitla1971
Enthusiast
Enthusiast

Thank you so much, i will just look at the total amount.

So no need to look at individual cpu counters for %CSTP.

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jitla1971
Enthusiast
Enthusiast

Can %RDY be over 10% but %CSTP less than 3%

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memaad
Virtuoso
Virtuoso

Hi,

I dont think so. But in your case, %CSTP is huge. Which clearly explains about the  over commitment of vCPU.

Regards

Mohammed

Mohammed | Mark it as helpful or correct if my suggestion is useful.
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CedricAnto
VMware Employee
VMware Employee

Just noticed this thread,

To answer your question "do i need to expand the vm and check %CSTP is less than 3% for each cpu or do i just look at the total like in the screenshot."

You would need to look at the cumulative value to ascertain how time the VM Co-Stopped and thereby had performance degradation.

For a more elaborate explanation of CSTP , please look at my blog post

http://virtualknight.wordpress.com/2014/05/09/esxtop-cstp-explained/

Cedric http://in.linkedin.com/in/cedricrajendran/ http://virtualknightz.com/
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