Thread: Intel Xeon PHI?
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Old 2020-11-18, 20:09   #64
ewmayer's Avatar
Sep 2002
República de California

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Finally completed a bunch of proof-of-principle coding/testing re. the p-1 algo which will debut in Mlucas v20 yesterday, had a little time to play with the KNL I setup with Ubuntu 19.10 again - on boot, once it gets to the Ubuntu-load screen, htting Esc has no effect, it simply continues on to PSOD (purple screen of death) as before. Again, my expectation was that the KNL would need some enterprise/server flavor of Linux, possibly also a custom Intel software stack. Did a bit of digging:

o From the Let's Buy GIMPS a KNL thread, post #43: "it comes preconfigured with all the tools and CentOS", said Linux distro being a free enterprise-oriented fork of Redhat, whose own enterprise distro, RHEL, requires a paid subscription.

o Intel's website, OTOH, describes the Intel Manycore Platform Software Stack:
Manycore Platform Software Stack." is necessary to run the Intel® Xeon Phi Coprocessor. Users often call this stack "MPSS" for short. It is dependent on Linux kernels 2.6.34 or later , and it has been tested to work with specific versions of 64-bit Operating Systems:

o Red Hat Enterprise 6.0, 6.1, 6.2, 6.3, 6.4 and 6.5 (for MPSS 3.2 and earlier releases); versions 6.3, 6.4, 6.5, 6.6 and 7.0 (MPSS 3.3 and 3.4), versions 6.4, 6.5, 6.6 and 7.1 (MPSS 3.5), versions 6.7, version 7.2 (MPSS 3.6 and 3.7) and version 7.3 (MPSS 3.8)
o SuSE Linux Enterprise Server (SLES) 11 SP1 and SP2 (MPSS 2.1), SuSE Linux Enterprise Server (SLES) 11 SP2 and SP3 (MPSS 3.3), SuSE 11 SP2 and SP3, SuSE 12 (MPSS 3.4), SuSE 11 SP3 and SuSE 12 (MPSS 3.5), SuSE 11 SP4, SuSE 12 SP1 (MPSS 3.6 and 3.7), SuSE 12 SP2 (MPSS 3.8)
o Microsoft* Windows 7 Enterprise SP1, Windows 8/8.1 Enterprise, Windows 10, Windows Server 2008 R2 SP1, Windows Server 2012 and Windows Server 2012 R2

The readme files (referenced in the Download section) have more information on how to build and install the stack.

The open source updates we have made are in support of the instruction set, the ABI, initializing and controlling an SMP on-a-chip, and the glue software to support the coprocessor communication with the host system. The changes in the Linux kernel are primarily for three reasons:

o Numerous little changes to support the unique combination of an Intel® Pentium® processor core that also supports 64-bits including the Intel® Initial Many Core Instructions (Intel® IMCI).
o Power management, which is a feature not associated with the original Pentium processors. Power management is much more important when you have up to 61 cores on a single die
o The Intel® Many Integrated Core (MIC) check architecture, also a feature not present in the original Pentium processor designs.

The Symmetric Communications InterFace (SCIF) is included in the RPM bundle. SCIF provides a mechanism for inter-node communications within a single platform. A node, for SCIF purposes, is defined as either a Intel® Xeon Phi Coprocessor or the Intel® Xeon® processor. In particular, SCIF abstracts the details of communicating over the PCI Express bus. The SCIF APIs are callable from both user space (uSCIF) and kernel-space (kSCIF).
Now if CentOS works as advertised, it should be drop-in-able in place of RHEL, right? And are all those Intel special tools likely must-haves, or nice-to-haves? (E.g. the SCIF sounds like something people with multiple Xeon processors might want or need, single-Xeon-ers like me less so.)
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