Processor 'steal', the horrifying monster explained

jsg

@dev_vps said:
For my VPS, the core is dedicated (with both its HWT). That is why it shows one socket with 2 virtual CPU.

Maybe Windows is different. Me lacking experience with Windows.

Neoon

@jsg said:

@dev_vps said:
For my VPS, the core is dedicated (with both its HWT). That is why it shows one socket with 2 virtual CPU.

Maybe Windows is different. Me lacking experience with Windows.

That's just the task manager, left click on it Change Graph => Logical Processors.

rustelekom

To be honest, me personally always was think that VDS is old term and mostly used by Russian spoken users term. Never seen any VDS offer from western host. VDS term may be used in 2003-2008 yeats, but then were silently disappear. From those times some oldest Russian or Russian spoken hosts use VDS in their domains: FirstVDS, ruVDS and so on. I could recall when we use Hsphere (that was very long time ago) in their menu i seen VPS and not VDS. But again, of course you can use any term what you want.

rm_

@dev_vps said: For my VPS, the core is dedicated (with both its HWT). That is why it shows one socket with 2 virtual CPU.

So, what does it matter that it shows 1 or 2? How do you know there's no other customer using the same core? You do not. At least not from the pretty graph in your Windows app, since it doesn't show any equivalent for "steal %". So maybe from some performance testing only, to verify it's the same at all times. Or have to simply trust the host actually following up on their "dedicated CPU" promise.

@rustelekom said: To be honest, me personally always was think that VDS is old term and mostly used by Russian spoken users term. Never seen any VDS offer from western host. VDS term may be used in 2003-2008 yeats, but then were silently disappear. From those times some oldest Russian or Russian spoken hosts use VDS in their domains: FirstVDS, ruVDS and so on.

Thank you, this is exactly my observation too.

dev_vps

@rm_ said:

@dev_vps said: For my VPS, the core is dedicated (with both its HWT). That is why it shows one socket with 2 virtual CPU.

So, what does it matter that it shows 1 or 2? How do you know there's no other customer using the same core? You do not. At least not from the pretty graph in your Windows app, since it doesn't show any equivalent for "steal %". So maybe from some performance testing only, to verify it's the same at all times. Or have to simply trust the host actually following up on their "dedicated CPU" promise.

I trust what my provider has told me.

My applications are highly cpu intensive and running for 5+ months with no issues and no downtime. Having 16GB memory for the VPS helps as well.

The cost for VPS is $25 per quarter and in my opinion, it is pretty reasonably priced.

I will look for any windows app that can benchmark steal time.

drunkendog

@dev_vps said:

@rm_ said:

@dev_vps said: For my VPS, the core is dedicated (with both its HWT). That is why it shows one socket with 2 virtual CPU.

So, what does it matter that it shows 1 or 2? How do you know there's no other customer using the same core? You do not. At least not from the pretty graph in your Windows app, since it doesn't show any equivalent for "steal %". So maybe from some performance testing only, to verify it's the same at all times. Or have to simply trust the host actually following up on their "dedicated CPU" promise.

I trust what my provider has told me.

My applications are highly cpu intensive and running for 5+ months with no issues and no downtime. Having 16GB memory for the VPS helps as well.

The cost for VPS is $25 per quarter and in my opinion, it is pretty reasonably priced.

I will look for any windows app that can benchmark steal time.

$25/qtr for a Windows VPS with $16 GB ram is almost certainly into deadpool territory, and it's very hard to find a deal with that value right now so your example isn't completely relevant. You'd be looking at $50/qtr for a standard VPS rn at that price range.

AXYZE

@dev_vps said:
For my VPS, the core is dedicated (with both its HWT). That is why it shows one socket with 2 virtual CPU.

if the application is cpu intensive, VDS will save load of headaches.

It is exactly what it says - your vCPU is on one processor/socket. It has nothing to do with cores being dedicated. If you have dedi server with 2 sockets then it will show 2 sockets, so then you think its not dedicated?

In NetCup root server you can split 2 vCPUs into two sockets if you want to. Then Windows will show you 2 sockets, 2 vCPU, but it will be still dedicated.

Usually it is not something you want because of latency in communication between cores (even communication between CCXes on AMD EPYC is huge deal, let alone different socket), but if you want separation then you go with it.

dev_vps

@drunkendog said:

$25/qtr for a Windows VPS with $16 GB ram is almost certainly into deadpool territory, and it's very hard to find a deal with that value right now so your example isn't completely relevant. You'd be looking at $50/qtr for a standard VPS rn at that price range.

I posted, under Requests, for a custom VPS requiring dedicated core (with both threads) explaining that I will be running machine learning based algorithms. And it will take average 50-60 percent cpu usage with hitting 100 percent for extended times.

I got this custom VPS. I have been using the VPS for more than five months with absolutely no issues.

https://browser.geekbench.com/v5/cpu/7347949

chocolateshirt

@jsg said:

@Neoon said:
Well, there is a good quote:

"Steal time is the percentage of time a virtual CPU waits for a real CPU while the hypervisor is servicing another virtual processor."

Which brings it to the point.

Yes, correct.
But (a) we are talking about microseconds, and (b) if the virtual processor (aka vCore) of a VM actually is just say, 25% of a HWT - and again, it doesn't know about that

You can check CPU performance roughly with GeekBench, if CPU allocated 100% then the value should be the usual benchmark score, like single core Ryzen 3900 ~ 1000-1300, Xeon E-2276G around 1200-1300, and Ryzen 5990x around 1500-1650

rm_

@dev_vps said: I trust what my provider has told me.

Sure, but then no point posting a picture on forums, saying "look, this proves I got dedicated cores".

@dev_vps said: For my VPS, the core is dedicated (with both its HWT). That is why it shows one socket with 2 virtual CPU.

IOW there's no "this is why" relation between the screenshot, and the cores being dedicated (or not).

rustelekom

I think customer can detect that core is not dedicated to his server by checking "steal" column in top utility output.

jsg

@rustelekom @rm_ (and others interested)

Some - not russian - providers do call VM products with a dedicated HWT 'VDS'.

That said, I'm absolutely willing to use another term, provided that it is relatively short, actually makes sense (unlike e.g. 'root server') and is in current use at some providers.

In other words: I get your point and I do mostly agree but I don't know of any better term meeting the above mentioned criteria.

AlwaysSkint

@jsg Congrats on new tag.

yorch

@Neoon said:

@jar said:
0.00% iowait is ideal but you won't sustain it even on dedicated hardware. It's part of running a server. Shared boxes are shared boxes, and thus they'll always be.

On Virmach, I often do see 60% indeed.

However, a bunch of Virtual Machines I rented, got less than 1% steal.

Usually it goes somewhere between 1-2%, some spike to 5% sometimes.

Was curious what are you using to collect and chart that for your server?
Thanks

Neoon

@yorch said:

@Neoon said:

@jar said:
0.00% iowait is ideal but you won't sustain it even on dedicated hardware. It's part of running a server. Shared boxes are shared boxes, and thus they'll always be.

On Virmach, I often do see 60% indeed.

However, a bunch of Virtual Machines I rented, got less than 1% steal.

Usually it goes somewhere between 1-2%, some spike to 5% sometimes.

Was curious what are you using to collect and chart that for your server?
Thanks

Selfcoded stuff, not public.

tmyers

Interesting thread. In our past lives, @jbiloh and I discussed offering something like 64 core ARM servers pre-packaged with SolusVM specifically for the low end crowd. Our goal was the ability to offer a dedicated core at a price point of like $2.50/mo, and the provider would make something like 50% gross margin without overselling.

I'm surprised we haven't seen a service provider come out with an ARM option yet, and perhaps they have; admittedly since leaving the industry I haven't exactly paid the closest attention to new developments.