Investigate use of SMT setting file #48

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opened 2022-10-31 21:36:55 +00:00 by NGnius · 1 comment

NGnius commented

2022-10-31 21:36:55 +00:00

(Migrated from github.com)

Describe what you'd like to be able to do
Investigate toggling SMT with the dedicated sysfs file /sys/devices/system/cpu/smt/control instead of (or in conjunction with) disabling every second thread.

Describe alternatives you've considered
The current implementation works, but if there's a less janky way I'd prefer that.

Additional context
The file /sys/devices/system/cpu/smt/control is rw with root and seems to accept on or off(?) as input to set SMT mode. There's also /sys/devices/system/cpu/smt/active which is ro but is an integer/bool (0 is off, 1 is on) which can be used to determine the SMT status. I don't know how this affects cpu# listings in /sys/devices/system/cpu/.

Originally mentioned here https://github.com/ValveSoftware/SteamOS/issues/864#issuecomment-1263493809
(Aside: Valve please make this project obsolete)

**Describe what you'd like to be able to do** Investigate toggling SMT with the dedicated sysfs file `/sys/devices/system/cpu/smt/control` instead of (or in conjunction with) disabling every second thread. **Describe alternatives you've considered** The current implementation works, but if there's a less janky way I'd prefer that. **Additional context** The file `/sys/devices/system/cpu/smt/control` is rw with root and seems to accept `on` or `off`(?) as input to set SMT mode. There's also `/sys/devices/system/cpu/smt/active` which is ro but is an integer/bool (0 is off, 1 is on) which can be used to determine the SMT status. I don't know how this affects cpu# listings in `/sys/devices/system/cpu/`. Originally mentioned here https://github.com/ValveSoftware/SteamOS/issues/864#issuecomment-1263493809 (Aside: Valve please make this project obsolete)

👍 1

NGnius commented

2022-12-03 19:11:58 +00:00

(Migrated from github.com)

This is mostly implemented. Pastaq pointed out that it's not all hooked up, so I'm going to leave this open while waiting for that change