[cgl_discussion] CONFIG_HYPERTHREADING ??

Randy.Dunlap rddunlap at osdl.org
Mon Oct 7 18:04:14 PDT 2002


I was expecting to see something that implements CONFIG_HT or

* Requirements meeting minutes from 2002-08-26:

 - already in kernel 2.4.19.
 - Result:  Accept as Core in 1.0.1 with PROVISO:
   - WITH PROVISO: that it can be configured out, even on hardware
   platforms that support it.
   - REASON: ISVs currently charge per-cpu, this makes it appear there
   are more CPUs, so customers may not want it.  Also, some workloads
   may not benefit from it.
 AR: Khalid to asses work to make configurable, work with an Intel rep.

* and Requirements meeting minutes from 2002-09-06:

 Newly proposed items (i.e., going into Requirements 1.1):
 Hyperthreading -- Core 1.1
 UPDATE_0906: Move to Configurable 1.1 -- Platform-specific.

* and OSDL CGL Requirements spec. v1.1:

 Requirement: 2.8 Hyperthreading of CPUs
 Version Assignment: Configurable 1.1

Was I mistaken to be expecting this, or is this still an outstanding

Current status is that Hyperthreading can be disabled on the
Linux kernel command line by using "noht" or can be disabled
(usually) in the BIOS SETUP, but not as a kernel build option.

This could easily be enough ways to disable it, but it's not
matching the Requirements spec IMO.


  "In general, avoiding problems is better than solving them."
  -- from "#ifdef Considered Harmful", Spencer & Collyer, USENIX 1992.

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