wikiActivate SATA Link Power Management in OPNsense
FreeBSD (and thus also OPNsense) allows to set different settings for the power management of the SATA interface (SATA Link Power Management). In this example we show how enabling SATA Device Initiated Power Management (DIPM) via Tuneable hint.ahcich.0.pm_level = 1 reduces power consumption by about 1 watt.
Configuration options
The FreeBSD AHCI driver allows to set different settings for the power management of the SATA interface via the tuneable variable hint.ahcich.X.pm_level. The following configuration options are selectable:[3]
- 0 - SATA link power management is disabled (default).
- 1 - SATA device is allowed to initiate PM state change (DIPM - Device Initiated Power Management), host is passive.
- 2 - Host initiates PARTIAL PM state transition each time port becomes inactive.
- 3 - Host initiates SLUMBER PM state transition each time port becomes inactive.
- 4 - The driver initiates the PARTIAL PM state transition 1ms after the port becomes idle.
- 5 - The driver initiates the SLUMBER PM state transition 125ms after the port becomes inactive.
Example IoT Firewall
In the following example, a Thomas-Krenn Edge 4L Firewall with the following configuration is used:
- BIOS version: (information to follow)
- RAM: 2 GB DDR3
- SSD: 120 GB ATP A600Sc (AF120GSTIC-T22) with Power Loss Protection
- Headless operation (no attached monitor, keyboard, mouse) with two active NICs (1 Gbit/s)
- OS : OPNsense 23.1.9-amd64 / FreeBSD 13.1-RELEASE-p7
- Default configuration
- SSH server enabled (LAN port)
- os-smart plugin and drivedb.h update[4]
- Ambient temperature: 23.9 - 24.4 °C
- Power measurement of the whole system using a Christ Electronic CLM1000-Professional Plus connected before the power supply (Delta Electronics ADP-36PH B, 12V / 3A / 36W, Efficency Class VI) of the DC3455-4-4F
| hint.ahcich.0.pm_level | 120 GB ATP A600Sc SSD
AF120GSTIC-T22 FW T0205B
|
128 GB ATP A600Sv SSD
AT128GSTIC-TM2 FW SBFMT1.3
|
120 GB ATP A600Sc TM1 mSATA SSD[note 1]
(AF120GSMHI-TM1, FW Q0303B) | ||||
|---|---|---|---|---|---|---|---|
| System
Idle Power |
SSD Temp.
Board (ID 194) |
SSD Temp.
Controller (ID 231) |
System
Idle Power |
System
Idle Power |
SSD Temp.
Board (ID 194) |
SSD Temp.
Controller (ID 231) | |
| 0 | 5.9 - 7.7 Watt | 53 °C | 73 °C | 5.4 - 7.4 Watt | 7.6 - 10.4 Watt | 55 °C | 63 °C |
| 1 | 4.6 - 6.8 Watt | 44 °C | 44 °C | 4.6 - 6.4 Watt | 6.8 - 9.1 Watt | 47 °C | 47 °C |
| 2 | 5.0 - 6.5 Watt | 45 °C | 45 °C | (not tested) | (not tested) | ||
| 3 | 5.0 - 6.9 Watt | 45 °C | 45 °C | ||||
| 4 | 4.9 - 6.2 Watt | 45 °C | 45 °C | ||||
| 5 | 5.0 - 6.7 Watt | 47 °C | 50 °C | ||||
| Savings at pm_level = 1 | ~ 1 Watt | ~ 9 °C | ~ 29 °C | ~ 0.8 - 1 Watt | ~ 0.8 - 1 Watt | ~ 8 °C | ~ 16 °C |
Footnote:
- ↑ Testsystem LES compact 4L, including LTE modem
References
- ↑ system: name unknown tunables as "environment" (github.com/opnsense/core, 17.07.2023)
- ↑ Support SATA Link Power Management - savings of ~1 watt (forum.opnsense.org, 22.06.2023)
- ↑ ahci(4) - FreeBSD Manual Pages (man.freebsd.org)
- ↑ drivedb.h: Add ATP SATA III SSDs (github.com/smartmontools)
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Author: Werner Fischer Werner Fischer, working in the Knowledge Transfer team at Thomas-Krenn, completed his studies of Computer and Media Security at FH Hagenberg in Austria. He is a regular speaker at many conferences like LinuxTag, OSMC, OSDC, LinuxCon, and author for various IT magazines. In his spare time he enjoys playing the piano and training for a good result at the annual Linz marathon relay.
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