Thread: Intel Xeon PHI?
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Old 2020-12-02, 20:33   #148
ewmayer
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Sep 2002
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Just did a reboot and had a look at the CPU Configuration menu in the BIOs:

o CPU freq = 1.4GHz and not BIOS-adjustable (nor the min.max ratios), L1 = 4352KB (4.25MB), L2 = 34816KB (34MB),

o HT is enabled by default, since I found no gain from using it in my Mlucas timing tests, disabled it to see if that makes a difference for my current 1-thread-per-core running

Under the Advanced Power Management Configuration Power Technology menu:

o Config TDP submenus not shown

o EIST (P-states): "EIST (Enhanced Intel SpeedStep Technology) allows the system to automatically adjust processor voltage and core frequency to reduce power consumption and heat dissipation. The options are Disable and *Enable*" -- basically, a form of auto-throttling, I disabled, which should be safe to do with my case in side-panel-removed form with the resulting low CPU temps (I ordered the baking sheet as my first side-opening mesh-covering solution attempt, btw). Note the sidebar infopane adds "When disabled, CPU frequency is set at max non-turbo", which means the aforementioned 1.4GHz. But "non-Turbo" implies there might be an available "turbo" mode - that might refer to a particular version of the CPU which has the clock unlocked, though.

o CPU C State Control -- see nothing of interest there

o CPU T State Control (Available when Power Technology is set to Custom): has a single submenu, ACPI (Advanced Configuration Power Interface) T-States: "Select Enable to support CPU throttling by the operating system to reduce power consumption. The options are *Enable* and Disable" -- switched to Disable, saved changes, booted the OS, fired up big 64M-FFT F30 job on 64 cores, wait for next ~10-min checkpoint update ... and no discernible speed change. So unless someone else has any bright ideas, looks like we are more or less maxed out already at the default settings.
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