[vfio-users] Regarding ACS support

[Erik Adler]

A couple of us are using Xeons over at

https://virtualkvm.com

Personally I have found the Xeon E5-2620v3 to have a “nice” price to
performance ratio.

Pros – ACS on root ports, low power, 6 cores, HT, 40 lanes PCIe
Cons - RAM speed is “only” 1866 MHz DDR4

Many motherboards that support Xeons will have some sort of “VGA”
contact for video on them.
The reason being many Xeons do not have graphics hardware built in and
dropping a GPU into a server board is not expected.

Chipsets like the AST2400 will pump 1920x1080 though that VGA contact.
For about $10 on ebay you can get an active VGA to HDMI HD converter
of you want hdmi.

The segment that becomes interesting is the “WS” or work station
boards that work with Xeons.
Its not unusual to find six full length (I have seven) PCIe x16 slots
and have built in graphics on the motherboard.
WS boards are a wacky combination of server technology mixed with the
desktop. Having a mix like IPMI, HD Audio, dual Xeons, tons of USB
ports, ECC and over clocking on a C612 motherboard? Yup! All that and
not having to worry about your root ports. A nice mix.

Just my two cents


On Sun, Oct 25, 2015 at 4:54 PM, Zir Blazer <zir_blazer at hotmail.com> wrote:
> I don't have any type of Blogger account to post a comment here:
> http://vfio.blogspot.com.ar/2015/10/intel-processors-with-acs-support.html
> So instead I drop an E-Mail.
>
>
> All the LGA 2011 (Sandy Bridge-E, Ivy Bridge-E) and LGA 2011-3 (Haswell-E
> and next to come Broadwell-E) Core i7s are actually rebranded Xeons E5,
> they're based on the same physical dies. Its not surprising that they have
> ACS, but more that Intel did not disable it in these parts. As LGA 2011 Core
> i7 are a subset of Xeons E5, Xeons E3 are pretty much a superset of consumer
> LGA 1155/1150/1151 Core i5/i7 (They also use the same dies), that's why they
> don't support ACS.
> Skylake-E is supposedly for 2017. The -E platform is usually a generation or
> two behind the consumer one, only during the initial Sandy Bridge generation
> and the recent Haswell era you had consumer and enterprise platforms with
> the same CPU architecture. Now you have consumer Skylake and enterprise
> Haswell-E, once again, a two generation gap.
>
> The latest Xeons E3 V5 Skylake has also been recently released:
> http://www.cpu-world.com/news_2015/2015102001_Intel_Greenlow_platform_and_Xeon_E3-1200_v5_series_launched.html
> I DO NOT suggest to get one right now since Intel "forgot" to enable a
> feature, SGX, and you need to wait for a new Stepping for it:
> http://www.cpu-world.com/news_2015/2015100301_Intel_to_enable_Software_Guard_Extensions_on_Skylake_processors.html
> Also, there are claims that Intel has limited Xeons E3 V5 with consumer
> Motherboards and that you CANNOT USE them in non-C Chipsets. They will not
> boot based on published tests. So if you want the new Xeons E3 V5, you need
> a true Server or Workstation Motherboard. May as well use them with DDR4
> Unbuffered + ECC RAM.
>
>
> Should you want LGA 2011-3, check the full Processor list here:
> https://www.pugetsystems.com/labs/articles/Intel-CPUs-Xeon-E5-vs-Core-i7-634/
>
> Besides the standard Core i7 5820K, you also have the Xeon E5-1620V3. It is
> an actually interesing Processor since it works more as an entry level
> alternative. It is a humble Quad Core and it cost around 300 U$D, while the
> Core i7 5820K has 6 Cores but cost 400 U$D. The Xeon has also the full 40
> PCIe Lanes while the 5820K is the only model to have 28 (Since Intel had to
> artificially differenciate it from the Ci7 5930K, causing that due to a
> single model in the entire LGA 2011-3 lineup, you have Motherboards Manuals
> that needs to specify what PCIe Slots and features works or not depending on
> if you use a Ci7 5820K or anything else). Also, at 300 U$D, the Xeon
> E5-1620V3 is around the cost of the LGA 1150 Xeon E3-1246V3/Core i7 4790
> Haswell, and specs are also around the same, so expect that type of
> performance.
>
> With XenGT and KVMGT coming (Renamed to Intel GVT-g), a very important thing
> is that LGA 2011 based Processors do NOT have integrated GPU. You will have
> to choose between having 4+ Cores with ACS support or GPU virtualization of
> the IGP. Xeons E3 with no IGP (Like the Xeon E3-1241V3) are excluded for
> obvious reasons, and since Intel seems to price the IGP versions around 20
> U$D or so more than the IGP less ones, it is rather stupid to NOT purchase
> the models with IGP considering that KVMGT could be a killer feature.
>
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