NPT is already present in ESX 3.5. You may have read some old slide somewhere, but on ALL VMWare documentation (both internal and external) VMWare acknowledges the execution and implementation of NPTs in ESX 3.5. staring right at a slide deck from VMWare right now that states as such. We're running it in our lab right now on B3 Barcelonas with no issue whatsoever.
Sorry for the completely off post.
But I'm really curious, Mr. Dave Graham, did you eventually get barcelona running on your quad-fx board?
I know quad-fx is officially dead now, but maybe if it's finally working with quadcores its still worth getting one of these ancient boards... and who knows, some mobo maker might even do a quad-fx mobo with some more recent chipset even despite amd giving up on the platform.
Alternatively, is it ever possible that a server board will work with normal unbuffered ram?
hey, never got around to it...got tied into testing Tyan's GT28 systems (the dual twin 1U Johan talked about with regards to CeBit.) Have spent most of my time trying to regress BIOS issues for production units there. However, ESX 3.5 is running quite happily on Barcelona B3 2352s using Tyan S3992-E boards. ;)
I am searching for a way to verify this, but I heard at VMWorld 2008 (March 2008) in a session by VMWare architect Richard brunner that is was going to be enabled in one of the upcoming updates of 3.5.
Do you have proof? :-) No issues doesn't mean that NPT is enabled.
i can't give you access to VMWare internal documentation, so, i'll present what I can to you. you can email me directly if you wish. Talk to Kris Kubicki for my EMC email address.
In theory a marginal design advantage like this could result in a tangible performance benefit. But there are far greater design advantages (integrated memory controller) that still aren't able to redeem the lackluster overall speed.
It is too little in most apps, but not in virtualized apps. NPT gives us a 10-20% performance difference.. far from marginal. If you consider that page tables updates can cost from 4 to a 1000 time more cycles in a virtualized environment than in a native one, it is clear that TLB flushes are a lot more costly.
You are right in a native environment, but wrong about virtualized servers: TLB size does matter there!
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flicker180 - Monday, March 17, 2008 - link
Johan,NPT is already present in ESX 3.5. You may have read some old slide somewhere, but on ALL VMWare documentation (both internal and external) VMWare acknowledges the execution and implementation of NPTs in ESX 3.5. staring right at a slide deck from VMWare right now that states as such. We're running it in our lab right now on B3 Barcelonas with no issue whatsoever.
cheers,
Dave Graham
Visual - Tuesday, March 18, 2008 - link
Sorry for the completely off post.But I'm really curious, Mr. Dave Graham, did you eventually get barcelona running on your quad-fx board?
I know quad-fx is officially dead now, but maybe if it's finally working with quadcores its still worth getting one of these ancient boards... and who knows, some mobo maker might even do a quad-fx mobo with some more recent chipset even despite amd giving up on the platform.
Alternatively, is it ever possible that a server board will work with normal unbuffered ram?
flicker180 - Tuesday, March 18, 2008 - link
Visual,hey, never got around to it...got tied into testing Tyan's GT28 systems (the dual twin 1U Johan talked about with regards to CeBit.) Have spent most of my time trying to regress BIOS issues for production units there. However, ESX 3.5 is running quite happily on Barcelona B3 2352s using Tyan S3992-E boards. ;)
cheers,
Dave
JohanAnandtech - Tuesday, March 18, 2008 - link
I am searching for a way to verify this, but I heard at VMWorld 2008 (March 2008) in a session by VMWare architect Richard brunner that is was going to be enabled in one of the upcoming updates of 3.5.Do you have proof? :-) No issues doesn't mean that NPT is enabled.
flicker180 - Tuesday, March 18, 2008 - link
Johan,i can't give you access to VMWare internal documentation, so, i'll present what I can to you. you can email me directly if you wish. Talk to Kris Kubicki for my EMC email address.
cheers,
dave
OndrejSc - Monday, March 17, 2008 - link
In theory a marginal design advantage like this could result in a tangible performance benefit. But there are far greater design advantages (integrated memory controller) that still aren't able to redeem the lackluster overall speed.JohanAnandtech - Tuesday, March 18, 2008 - link
It is too little in most apps, but not in virtualized apps. NPT gives us a 10-20% performance difference.. far from marginal. If you consider that page tables updates can cost from 4 to a 1000 time more cycles in a virtualized environment than in a native one, it is clear that TLB flushes are a lot more costly.You are right in a native environment, but wrong about virtualized servers: TLB size does matter there!