AVX2 and AVX-512 frequencies for W-2014

By: Jeff S. (fakity.delete@this.fake.com), August 16, 2018 6:19 am
Room: Moderated Discussions
Travis (travis.downs.delete@this.gmail.com) on August 15, 2018 12:52 pm wrote:
> Adrian (a.delete@this.acm.org) on August 15, 2018 12:17 am wrote:
>
> > You have probably seen that Anandtech has just published all the
> > turbo frequencies for most Xeon W models, but not for this one.
>
> Yes, they excluded the non-turbo models W-2104 and W-2102, unfortunately. They also don't make
> it clear where they sourced their info (since I'd like to go to the source if it is public).
>
> > I have no idea which are the frequencies for W-2104, but a reasonable
> > supposition would be 3.0 GHz for AVX2 and 2.8 GHz for AVX-512.
> >
> > For an only 4-core processor, it is very unlikely that lower frequencies would be needed.
> >
> > Another likely possibility is that it matches the behavior of W-2123. In that case
> > the AVX-512 and AVX2 frequencies would be the same, but 3.1 GHz would be the 2-core
> > AVX2/-512 frequency and 3.0 GHz would be the 4-core AVX2/-512 frequency.
>
> Right. I don't think there is any physical limitation here: if W-2123 can do 3.5/3.5/3.4/3.4,
> the very similar W-2104 could perhaps just do it's base frequency of 3.2 in all modes, no
> matter how many active cores. It is just a matter of how Intel wanted to segment it.
>
> Is anyone aware of any out-of-the box thing to either measure this or read the frequency
> from MSRs (I forget if these modes are both exposed, I think so though).

AFAIK, you still have to do a heuristic from the APERF/MPERF register for lack of a direct queryable register. See: kernel patch for active MHz calculation Just making the system call might be good enough for your purposes, since the AVX downclock window lasts like a full ms.

The AVX turbo offsets should be visible in BIOS, so you may not need to try dynamic measurements if you are just looking for the static turbo clock ranges and not what is actually achieved dynamically in the face of power limits.
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TopicPosted ByDate
AVX2 and AVX-512 frequencies for W-2014Travis2018/08/14 08:37 PM
  Should say W-2104 (NT)Travis2018/08/14 08:50 PM
  AVX2 and AVX-512 frequencies for W-2014Adrian2018/08/15 12:17 AM
    AVX2 and AVX-512 frequencies for W-2014Travis2018/08/15 12:52 PM
      AVX2 and AVX-512 frequencies for W-2014Jeff S.2018/08/16 06:19 AM
        AVX2 and AVX-512 frequencies for W-2014Travis2018/08/16 09:09 AM
        AVX2 and AVX-512 frequencies for W-2014Travis2018/08/23 11:25 PM
      AVX2 and AVX-512 frequencies for W-2014Adrian2018/08/16 11:31 PM
        AVX2 and AVX-512 frequencies for W-2014Travis Downs2018/08/17 08:16 AM
          AVX2 and AVX-512 frequencies for W-2014Adrian2018/08/17 10:29 AM
            AVX2 and AVX-512 frequencies for W-2014Travis2018/08/19 11:40 AM
    AVX2 and AVX-512 frequencies for W-2104Travis2018/08/23 10:49 PM
      AVX2 and AVX-512 frequencies for W-2104Adrian2018/08/24 02:32 AM
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