Date: Mon, 24 May 2010 15:30:05 -0400 From: John Baldwin <jhb@freebsd.org> To: freebsd-arch@freebsd.org Cc: Alexander Motin <mav@freebsd.org> Subject: Re: Event timers Message-ID: <201005241530.05116.jhb@freebsd.org> In-Reply-To: <4BFAA1F3.1070206@FreeBSD.org> References: <4BFAA1F3.1070206@FreeBSD.org>
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On Monday 24 May 2010 11:57:39 am Alexander Motin wrote: > Hi. > > You should agree that event timers code we have now (hardclock, > statclock and profclock source) is real mess. The code is completely > machine-dependent, many times duplicated (I have found 4 or 5 equal > implementations and many more trivial ones), very tangled and > inflexible. While it is acceptable for some platforms with single > interrupt source running on hz, x86 with it's many different timers > definitely doesn't look good. So I've decided to clean it. > > I have defined several points on that way: > 1*. clean low-level timer drivers from unrelated stuff, > 2*. make some common code machine-independent, > 3. write common driver API for event timers (alike to one we have now > for time counters) to make adding more drivers possible, > 4. add support for HPET as event timer in addition to time counter, > 5. add support for timers in one-shot mode (LAPIC and HPET). Have you looked at the dynamic ticks patches on hackers@? Those already include changes for 5), although he currently only has support for LAPIC and is working on adding HPET support. -- John Baldwin
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