Linux Erroneously Thinks Intel Bartlett Lake CPUs Run At 7GHz
With Intel's recently-launched Bartlett Lake P-core-only processors intended for the embedded market, there is a rather surprising oversight under Linux: the Intel P-State driver reporting a 7.0+ GHz clock speed. While many would yearn for a 7GHz CPU, the Core 9 273PE where this issue was discovered in reality can only boost up to 5.7GHz for its maximum turbo frequency.
A QNAP engineer has been posting patches this week for the Intel P-State driver to correct the scaling factor for the Bartlett Lake P-core processors. QNAP engineer Henry Tseng sums up simply:
This comes down to the wrong CPU scaling factor being propagated for Bartlett Lake processors. A six line patch to the Intel P-State CPU frequency scaling driver is then able to report the correct scaling factor and in turn the correct maximum frequencies for these P-core-only processors.
With Intel Bartlett Lake catering to the embedded market and edge computing where Linux is heavily used, it's surprising this issue was only uncovered and being patched now after these P-core CPUs are already shipping to customers. More so, surprising it's a QNAP engineer taking to getting this Linux kernel driver issue fixed rather than Intel engineers.
In any event, if you happen to have your hands on Intel Bartlett Lake, this patch series is what's being worked on for reporting the correct maximum frequency.
A QNAP engineer has been posting patches this week for the Intel P-State driver to correct the scaling factor for the Bartlett Lake P-core processors. QNAP engineer Henry Tseng sums up simply:
"On Bartlett Lake P-core only SKUs (e.g. Intel Core 9 273PE), cpuinfo_max_freq is reported as 7.0/7.3 GHz, exceeding the datasheet Max Turbo Frequency of 5.7 GHz."
This comes down to the wrong CPU scaling factor being propagated for Bartlett Lake processors. A six line patch to the Intel P-State CPU frequency scaling driver is then able to report the correct scaling factor and in turn the correct maximum frequencies for these P-core-only processors.
With Intel Bartlett Lake catering to the embedded market and edge computing where Linux is heavily used, it's surprising this issue was only uncovered and being patched now after these P-core CPUs are already shipping to customers. More so, surprising it's a QNAP engineer taking to getting this Linux kernel driver issue fixed rather than Intel engineers.
👁 Intel Bartlett Lake CPU SKU table
In any event, if you happen to have your hands on Intel Bartlett Lake, this patch series is what's being worked on for reporting the correct maximum frequency.