[Bug 955287] [NEW] Ubuntu should handle "hot" CPUs by taking preemptive action and warning users

[James Hunt]

Public bug reported:

If the kernel detects your CPU(s) is/are too hot currently (see bug
751689), the kernel calls /sbin/poweroff. This will provide a "graceful"
system shutdown. If /sbin/poweroff fails, the kernel just forcibly shuts
the system down. However, both strategies are last resorts and are
called when the system temperature has reached a critical level.

However, the kernel seems to emit an ACPI event when it detects the
CPU(s) are merely "hot". I suggest we consider adding an acpi hook to
attempt to avoid a "critical" scenario.

Currently, the user experience when "critical" gets hit is not good -
the system just shuts down with no warning whatsoever. This is alarming
in the extreme to users.

Ideas:

- proactively attempt to kill off power hogging processes (use powertop?)
- ramp fans to maximum and present the user with a warning window explaining what is happening.
- present the user with a window of high-power processes and ask *them* to select the processes they'd like to kill off in an effort
  to avoid a system shutdown.

Problems:

- it is unclear (to me atleast) how close (in terms of degrees
centigrade) "hot" and "critical" are (is it different for all CPUs ?) As
such, it is unclear how long (time) it might take for a system that is
hot to go critical and just shutdown.

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: acpi-support 0.140
ProcVersionSignature: Ubuntu 3.2.0-18.29-generic-pae 3.2.9
Uname: Linux 3.2.0-18-generic-pae i686
NonfreeKernelModules: nvidia
ApportVersion: 1.94.1-0ubuntu2
Architecture: i386
Date: Wed Mar 14 17:22:09 2012
InstallationMedia: Ubuntu 10.10 "Maverick Meerkat" - Release i386 (20101007)
ProcEnviron:
 TERM=xterm
 PATH=(custom, user)
 LANG=fr_CA.UTF8
 SHELL=/bin/bash
SourcePackage: acpi-support
UpgradeStatus: Upgraded to precise on 2012-01-12 (62 days ago)

** Affects: acpi-support (Ubuntu)
     Importance: Undecided
         Status: New


** Tags: apport-bug i386 precise

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https://bugs.launchpad.net/bugs/955287

Title:
  Ubuntu should handle "hot" CPUs by taking preemptive action and
  warning users

Status in “acpi-support” package in Ubuntu:
  New

Bug description:
  If the kernel detects your CPU(s) is/are too hot currently (see bug
  751689), the kernel calls /sbin/poweroff. This will provide a
  "graceful" system shutdown. If /sbin/poweroff fails, the kernel just
  forcibly shuts the system down. However, both strategies are last
  resorts and are called when the system temperature has reached a
  critical level.

  However, the kernel seems to emit an ACPI event when it detects the
  CPU(s) are merely "hot". I suggest we consider adding an acpi hook to
  attempt to avoid a "critical" scenario.

  Currently, the user experience when "critical" gets hit is not good -
  the system just shuts down with no warning whatsoever. This is
  alarming in the extreme to users.

  Ideas:

  - proactively attempt to kill off power hogging processes (use powertop?)
  - ramp fans to maximum and present the user with a warning window explaining what is happening.
  - present the user with a window of high-power processes and ask *them* to select the processes they'd like to kill off in an effort
    to avoid a system shutdown.

  Problems:

  - it is unclear (to me atleast) how close (in terms of degrees
  centigrade) "hot" and "critical" are (is it different for all CPUs ?)
  As such, it is unclear how long (time) it might take for a system that
  is hot to go critical and just shutdown.

  ProblemType: Bug
  DistroRelease: Ubuntu 12.04
  Package: acpi-support 0.140
  ProcVersionSignature: Ubuntu 3.2.0-18.29-generic-pae 3.2.9
  Uname: Linux 3.2.0-18-generic-pae i686
  NonfreeKernelModules: nvidia
  ApportVersion: 1.94.1-0ubuntu2
  Architecture: i386
  Date: Wed Mar 14 17:22:09 2012
  InstallationMedia: Ubuntu 10.10 "Maverick Meerkat" - Release i386 (20101007)
  ProcEnviron:
   TERM=xterm
   PATH=(custom, user)
   LANG=fr_CA.UTF8
   SHELL=/bin/bash
  SourcePackage: acpi-support
  UpgradeStatus: Upgraded to precise on 2012-01-12 (62 days ago)

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