imported>CoolieCoolster: Added non-breaking space to non-template file size, frequency, bitrate, and bandwidth values (via WP:JWB)

2024-04-25T23:52:55Z

Added non-breaking space to non-template file size, frequency, bitrate, and bandwidth values (via WP:JWB)

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{{more footnotes|date=May 2014}}
'''Platform Environment Control Interface''' ('''PECI''') is an [[Intel]] proprietary single wire [[serial interface]] that provides a communication channel between [[Intel processors]] and [[chipset]] components to external system management logic and thermal monitoring devices. Also, PECI provides an interface for external devices to read processor temperature, perform processor manageability functions, and manage processor interface tuning and diagnostics. Typically in server platforms, [[CPU]]s are the PECI slaves and [[Platform Controller Hub]] (PCH) is the PECI master, meanwhile in client segment, CPU is usually the PECI slave and [[Embedded controller|EC]]/[[Baseboard Management Controller|BMC]] is the PECI master. PECI was introduced in 2006 with the [[Intel]] [[Core 2 Duo]] [[microprocessor]]s.

Support for PECI was added to the [[Linux kernel]] version 5.18 in 2022.<ref name="phoronix-5.18">{{Cite web |title=Intel PECI Code To Be Mainlined With Linux 5.18 |url=https://www.phoronix.com/scan.php?page=news_item&px=Intel-PECI-Linux-5.18 |access-date=2022-03-02 |website=www.phoronix.com |language=en}}</ref>

== Thermal monitoring details ==
While previous thermal management technologies have made use of [[thermal diode]]s, PECI instead uses on-die digital thermal sensors (DTS). These sensors, after being calibrated at the factory, are able to provide digital data concerning processor [[temperature]] information. The PECI [[bus (computing)|bus]], allowing access to this data from [[chipset]] components, is a [[Proprietary hardware|proprietary]] single-wire interface with a variable data transfer speed (from 2 kbit/s to 2 Mbit/s).

From a control standpoint, the main difference between PECI and the previously used thermal monitoring methods is that PECI reports a negative value expressing the difference between the current temperature and the [[thermal throttling|thermal throttle]] point (at which the CPU reduces speed or shuts down to prevent damage due to overheating) instead of the absolute temperature. For example, for a CPU with maximal temperature of 85 °C and a current temperature reading of 35 °C, the value reported by PECI would be −50 °C.

== Advantages ==
Since the value reported by PECI takes into account internal processor information about safe [[operating temperature]]s, it alleviates the need for the [[BIOS]] or [[operating system]] to make potentially incorrect assumptions about this limit. Furthermore, it supports dynamic fan control with a high degree of accuracy, where fan speed can be progressively increased as the value approaches zero.

== See also ==
* [[Host Embedded Controller Interface]] (HECI)
* [[Thermal Monitoring 2]]

==References==
{{Reflist}}

== Sources ==
* [http://download.intel.com/design/Xeon/datashts/31491501.pdf Dual-Core Intel Xeon Processor 3000 Series Datasheet]
* [http://www.intel.com/Assets/PDF/datasheet/313355.pdf Dual-Core Intel Xeon Processor 5100 Series Datasheet]
* [http://download.intel.com/design/processor/datashts/31327808.pdf Intel Core 2 Extreme X6800 and Core 2 Duo E6000 and E4000 Sequence Features]

{{Intel technology}}

[[Category:X86 architecture]]
[[Category:Computer hardware cooling]]
[[Category:Intel products]]

Platform Environment Control Interface - Revision history

imported>CoolieCoolster: Added non-breaking space to non-template file size, frequency, bitrate, and bandwidth values (via WP:JWB)