| Message ID | 1333702969-28795-1-git-send-email-dmitry.antipov@linaro.org |
|---|---|
| State | New |
| Headers | show |
Dmitry, Thanks for this patch. Would you be willing to revise it a little to add some words about the *purpose* of timer slack. Thanks Michael On Fri, Apr 6, 2012 at 9:02 PM, Dmitry Antipov <dmitry.antipov@linaro.org> wrote: > Document PR_GET_TIMERSLACK and PR_SET_TIMERSLACK for prctl (2). > Document /proc/sys/kernel/timer_slack for proc (5). > > Signed-off-by: Dmitry Antipov <dmitry.antipov@linaro.org> > --- > man2/prctl.2 | 15 +++++++++++++++ > man5/proc.5 | 4 ++++ > 2 files changed, 19 insertions(+), 0 deletions(-) > > diff --git a/man2/prctl.2 b/man2/prctl.2 > index effad2a..dcf803f 100644 > --- a/man2/prctl.2 > +++ b/man2/prctl.2 > @@ -378,6 +378,21 @@ Return the current per-process machine check kill policy. > All unused > .BR prctl () > arguments must be zero. > +.TP > +.BR PR_GET_TIMERSLACK " (since Linux 2.6.28)" > +Return the current per-thread high-resolution timers slack, in nanoseconds. > +.TP > +.BR PR_SET_TIMERSLACK " (since Linux 2.6.28)" > +Set the current per-thread high-resolution timers slack. If arg2 is less than or > +equal to zero, system-wide default value is restored. The system-wide default can > +be read and set by /proc/sys/kernel/timer_slack (see > +.BR proc (5)). > +Otherwise, if arg2 is less than or equal to HRTIMER_MAX_SLACK (which is a kernel > +constant defined in include/linux/hrtimer.h), this value is set up as a new slack. > +Slack is not inherited across > +.BR fork (2); > +new process initially uses system-wide default slack, and new thread inherits > +it's slack from the group leader. > .SH "RETURN VALUE" > On success, > .BR PR_GET_DUMPABLE , > diff --git a/man5/proc.5 b/man5/proc.5 > index 54ccdd8..0493b6b 100644 > --- a/man5/proc.5 > +++ b/man5/proc.5 > @@ -2407,6 +2407,10 @@ date behind it indicates the time the kernel was built. > This file specifies the system-wide limit on the number of > threads (tasks) that can be created on the system. > .TP > +.IR /proc/sys/kernel/timer_slack > +This file specifies the system-wide default slack for > +high-resolution timers, in nanoseconds. > +.TP > .IR /proc/sys/kernel/zero-paged " (PowerPC only) " > This file > contains a flag. > -- > 1.7.7.6 >
diff --git a/man2/prctl.2 b/man2/prctl.2 index effad2a..dcf803f 100644 --- a/man2/prctl.2 +++ b/man2/prctl.2 @@ -378,6 +378,21 @@ Return the current per-process machine check kill policy. All unused .BR prctl () arguments must be zero. +.TP +.BR PR_GET_TIMERSLACK " (since Linux 2.6.28)" +Return the current per-thread high-resolution timers slack, in nanoseconds. +.TP +.BR PR_SET_TIMERSLACK " (since Linux 2.6.28)" +Set the current per-thread high-resolution timers slack. If arg2 is less than or +equal to zero, system-wide default value is restored. The system-wide default can +be read and set by /proc/sys/kernel/timer_slack (see +.BR proc (5)). +Otherwise, if arg2 is less than or equal to HRTIMER_MAX_SLACK (which is a kernel +constant defined in include/linux/hrtimer.h), this value is set up as a new slack. +Slack is not inherited across +.BR fork (2); +new process initially uses system-wide default slack, and new thread inherits +it's slack from the group leader. .SH "RETURN VALUE" On success, .BR PR_GET_DUMPABLE , diff --git a/man5/proc.5 b/man5/proc.5 index 54ccdd8..0493b6b 100644 --- a/man5/proc.5 +++ b/man5/proc.5 @@ -2407,6 +2407,10 @@ date behind it indicates the time the kernel was built. This file specifies the system-wide limit on the number of threads (tasks) that can be created on the system. .TP +.IR /proc/sys/kernel/timer_slack +This file specifies the system-wide default slack for +high-resolution timers, in nanoseconds. +.TP .IR /proc/sys/kernel/zero-paged " (PowerPC only) " This file contains a flag.
Document PR_GET_TIMERSLACK and PR_SET_TIMERSLACK for prctl (2). Document /proc/sys/kernel/timer_slack for proc (5). Signed-off-by: Dmitry Antipov <dmitry.antipov@linaro.org> --- man2/prctl.2 | 15 +++++++++++++++ man5/proc.5 | 4 ++++ 2 files changed, 19 insertions(+), 0 deletions(-)