X86 timing: Difference between revisions

From dankwiki
No edit summary
No edit summary
Line 2: Line 2:
* [[ACPI]] counter
* [[ACPI]] counter
* LAPIC counter
* LAPIC counter
* HPET
* HPET. Unprivileged programmability is limited by <tt>/proc/sys/dev/hpet/max-user-freq</tt> (in Hz):
<pre>[recombinator](1) $ cat /proc/sys/dev/hpet/max-user-freq
64
[recombinator](0) $ </pre>
* TSC since Pentium
* TSC since Pentium
* RTC ([http://fxr.watson.org/fxr/source/Documentation/rtc.txt?v=linux-2.6 Linux docs])
* RTC ([http://fxr.watson.org/fxr/source/Documentation/rtc.txt?v=linux-2.6 Linux docs])

Revision as of 02:46, 27 June 2009

  • PIT -- Programmable Interval Timer (eg Intel 8253)
  • ACPI counter
  • LAPIC counter
  • HPET. Unprivileged programmability is limited by /proc/sys/dev/hpet/max-user-freq (in Hz):
[recombinator](1) $ cat /proc/sys/dev/hpet/max-user-freq 
64
[recombinator](0) $ 
[recombinator](0) $ cat /proc/driver/rtc 
rtc_time	: 07:43:30
rtc_date	: 2009-06-27
alrm_time	: **:00:00
alrm_date	: ****-**-**
alarm_IRQ	: no
alrm_pending	: no
24hr		: yes
periodic_IRQ	: no
update_IRQ	: no
HPET_emulated	: yes
DST_enable	: no
periodic_freq	: 1024
batt_status	: okay
[recombinator](0) $ 
  • Linux clocksources vs clockevents