Messages in this thread | | | Date | Mon, 20 Jan 2003 22:55:29 -0800 | From | george anzinger <> | Subject | [PATCH NOTICE 2/3] High-res-timers part 2 (x86 platform code) take 25 |
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This is the platform part of the high-res timers for the x86.
Now available for 2.5.59 on sourceforge (see signature).
Changes since last time: Kconfig comment clean up by Randy Dunlap. Changes to the CPU frequency code in the hrtimer_tsc area. John Stultz's changes to make fast_gettimeoffset_quotient a static are included. Make file changes in arch/i386/kernel/time/Makefile ------------ Changes to the .../arch/i386/kernel/time/Makefile Moved the disable_tsc var to time.c so it can be shared. Picked up the do_timer.h changes in two addional sub archs.
CONFIG dependency added to not turn on stuff only needed when CONFIG_HIGH_RES = y. ----------
This patch, in conjunction with the "core" high-res-timers patch implements high resolution timers on the i386 platforms. The high-res-timers use the periodic interrupt to "remind" the system to look at the clock. The clock should be relatively high resolution (1 micro second or better). This patch allows configuring of three possible clocks, the TSC, the ACPI pm timer, or the Programmable interrupt timer (PIT). Most of the changes in this patch are in the arch/i386/kernel/timer/* code.
This patch uses (if available) the APIC timer(s) to generate 1/HZ ticks and sub 1/HZ ticks as needed. The PIT still interrupts, but if the APIC timer is available, just causes the wall clock update. No attempt is made to make this interrupt happen on jiffie boundaries, however, the APIC timers are disciplined to expire on 1/HZ boundaries to give consistent timer latencies WRT to the system time.
With this patch applied and enabled (at config time in the processor feature section), the system clock will be the specified clock. The PIT is not used to keep track of time, but only to remind the system to look at the clock. Sub jiffies are kept and available for code that knows how to use them.
Depends on the core high res timers patch.
This patch as well as the POSIX clocks & timers patch is available on the project site: http://sourceforge.net/projects/high-res-timers/
The 3 parts to the high res timers are: core The core kernel (i.e. platform independent) changes *i386 The high-res changes for the i386 (x86) platform hrposix The changes to the POSIX clocks & timers patch to use high-res timers
Please apply. -- George Anzinger george@mvista.com High-res-timers: http://sourceforge.net/projects/high-res-timers/ Preemption patch: http://www.kernel.org/pub/linux/kernel/people/rml - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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