Arm has officially joined the Compute Express Link (CXL) Consortium in a bid to enable its customers to implement the new CPU-to-Device interconnect and contribute to the specification. Arm was among a few major technology companies that was yet to join the CXL consortium and given the number of chips that use Arm’s IP, its support is hard to overestimate.

Arm is not completely new to CXL. The company has been participating in CXL workgroups and has provided technological and promotional resources to support development of the technology. The formal joining of the CXL consortium indicates the company’s commitment to provide its customers a full software framework to CXL, though the company does not say anything about plans to add appropriate logic to its upcoming AMBA PCIe Gen 5 PHY implementations.

Arm is a board member in the PCI SIG and the Gen-Z Consortium. Besides, the company supports its own CCIX interface for inter-package chip-to-chip interface. By supporting CXL, Arm will enable its clients to build CPUs or accelerators that support low-latency cache coherency as well as memory semantics between processors and accelerators.

Arm says that CCIX, which supports full cache coherency, will be used as an inter-package chip-to-chip interface for heterogeneous system-on-packages. Meanwhile, since this functionality is not in the scope of CXL at present, it will not compete against Arm’s version of CCIX.

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Source: Arm

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  • jeremyshaw - Friday, September 13, 2019 - link

    If OpenPOWER joins CXL, I think that will cover nearly all of the HPC industry (maybe Oracle, if they still do anything?).

    Looking at the list, Nvidia has joined as well (not only via Mellanox; Nvidia formally joined at some point).

    The consortium has added a lot of names to its list!
  • ksec - Saturday, September 14, 2019 - link

    Wow, I didn't Catch Nvidia joined as well, which leaves OpenPower as the only one not on the list?

    I have they have OpenCAPI, not too sure if they are going all in or abandon it.
  • melgross - Friday, September 13, 2019 - link

    I wonder who all of the “working” members are. In organizations like this one, not all of the members actually work on the standard, and just want to be there to keep up with what’s happening. I know from experience.
  • jeremyshaw - Friday, September 13, 2019 - link

    My best guess is the founding 9 members, mostly lead by Intel and their clients.

    The recent USB4 spec docs point out who were the contributors, and it's not that many companies nor people. One interesting thing I noted about the USB4 contributors, was Lenovo - all of the people on that team were Japanese.
  • Hul8 - Saturday, September 14, 2019 - link

    Lenovo probably has a research center in Japan, and that's the one responsible for their USB4 efforts?
  • Elstar - Saturday, September 14, 2019 - link

    I’d wager that everybody is joining CXL because Intel is too big to ignore. Basically everybody that makes high-performance PCIe boards has to join to stay relevant. This forces companies like Nvidia to join, even if they compete in other arenas. Ditto ARM.
  • mode_13h - Saturday, September 14, 2019 - link

    The diagram mentions "flit format". I assume that's not a typo, so what does it mean?

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