A utility for enabling/disabling hyperthreading
This Gem provides a simple cli utility named hyperctl that can check the
status of and [with appropriate permissions] enable/disable
hyperthreading/SMT/sibling cores on Linux via the
sysfs
pseudo filesystem. It should be compatible with most modern Linux
distributions as long as sysfs is mounted at /sysfs.
gem install hyperctl
bundle install
bundle exec rake install
Usage:
hyperctl
hyperctl (--enable | --disable) [--quiet]
hyperctl --status (--enable | --disable) [--quiet]
hyperctl -h | --help
hyperctl --version
Options:
--enable Enable hyperthreading.
--disable Diable hyperthreading.
--status Report hyperthreading state.
--quiet Suppress stdout.
--version Show version.
-h --help Show this screen.
0- success1- option parsing related error2- system error (Eg., permission denied)3- status does not match desired state
Prints the current status of hyperthreading on the system to the stdout.
Exits with 0 if no errors were encountered.
$ hyperctl
cpu0 : enabled - hypertheading: enabled
cpu1 : enabled - hypertheading: enabled
cpu2 : enabled - hypertheading: enabled
cpu3 : enabled - hypertheading: enabled
cpu4 : enabled - hypertheading: enabled
cpu5 : enabled - hypertheading: enabled
cpu6 : enabled - hypertheading: enabled
cpu7 : enabled - hypertheading: enabled
Attempt to enable or disable all hyperthread/SMT/sibling cores on the system.
Exits with 0 upon success, 2 for system errors, or 3 for state change
failures (unlikely).
With appropriate permissions to modify the appropriate sysfs entries:
$ sudo hyperctl --disable
cpu0 : enabled - hypertheading: disabled
cpu1 : enabled - hypertheading: disabled
cpu2 : enabled - hypertheading: disabled
cpu3 : enabled - hypertheading: disabled
cpu4 : disabled - hypertheading: disabled
cpu5 : disabled - hypertheading: disabled
cpu6 : disabled - hypertheading: disabled
cpu7 : disabled - hypertheading: disabled
$ echo $?
0
Without appropriate permissions:
$ hyperctl --disable
Permission denied @ rb_sysopen - /sys/devices/system/cpu/cpu4/online
$ echo $?
2
Checks the status of hyperthread/SMT/sibling cores on the system. Exits with
0 if the state matches the (--enable | --disable) option, otherwise with
3
System already in --disable state:
$ sudo hyperctl --status --disable
cpu0 : enabled - hypertheading: disabled
cpu1 : enabled - hypertheading: disabled
cpu2 : enabled - hypertheading: disabled
cpu3 : enabled - hypertheading: disabled
cpu4 : disabled - hypertheading: disabled
cpu5 : disabled - hypertheading: disabled
cpu6 : disabled - hypertheading: disabled
cpu7 : disabled - hypertheading: disabled
$ echo $?
0
System not in --enable state:
$ sudo hyperctl --status --enable
cpu0 : enabled - hypertheading: disabled
cpu1 : enabled - hypertheading: disabled
cpu2 : enabled - hypertheading: disabled
cpu3 : enabled - hypertheading: disabled
cpu4 : disabled - hypertheading: disabled
cpu5 : disabled - hypertheading: disabled
cpu6 : disabled - hypertheading: disabled
cpu7 : disabled - hypertheading: disabled
$ echo $?
3
Suppresses the stdout status message. Intended for usage from scripts.
$ sudo hyperctl --status --enable --quiet
$ echo $?
3
$ sudo hyperctl --status --disable --quiet
$ echo $?
0
This Gem is versioned according to the Semantic Versioning 2.0.0 specification.
Please log tickets and issues at github
- Fork it on github
- Make a local clone of your fork
- Create a topic branch. Eg,
feature/mousetrap - Make/commit changes
- Commit messages should be in imperative tense
- Check that
Rspecunit tests are not broken and coverage is added for new features -bundle exec rake spec - Documentation of API/features is updated as appropriate in the README
- When the feature is complete, rebase / squash the branch history as necessary to remove "fix typo", "oops", "whitespace" and other trivial commits
- Push the topic branch to github
- Open a Pull Request (PR) from the topic branch onto parent repo's
masterbranch
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