From: Grant Grundler <grundler@parisc-linux.org>
To: Matthew Wilcox <willy@debian.org>
Cc: Carlos O'Donell <carlos@baldric.uwo.ca>, parisc-linux@parisc-linux.org
Subject: Re: [parisc-linux] Generic light-weight syscall.
Date: Tue, 29 Jul 2003 12:51:30 -0600 [thread overview]
Message-ID: <20030729185130.GA22989@dsl2.external.hp.com> (raw)
In-Reply-To: <20030728174551.GC3840@parcelfarce.linux.theplanet.co.uk>
On Mon, Jul 28, 2003 at 06:45:51PM +0100, Matthew Wilcox wrote:
...
> > It might be too costly to do the sync'ing all the time, and too costly
> > for a fast gettimeofday to do a sync at the polling point.
If they all use the same clock source they won't drift.
> > gettimeofday. Do we even have such a fast clock on PA? What is the
> > fastest clock across the most boxes?
cr16
> You know, you don't even need kernel help for this. According to page
> 2-5 of the Kane book, the Interval Timer is accessible by non-privileged
> instructions.
One needs kernel help in determining the difference between CPUs
and handling CR16 rollover (mostly a problem for 32-bit machines).
But then user space can read CR16 and "normalize" the time.
grant
next prev parent reply other threads:[~2003-07-29 18:51 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-07-25 6:37 [parisc-linux] Generic light-weight syscall Carlos O'Donell
2003-07-25 11:37 ` Matthew Wilcox
2003-07-26 17:48 ` Carlos O'Donell
2003-07-26 18:00 ` Carlos O'Donell
2003-07-27 12:27 ` Grant Grundler
2003-07-28 15:57 ` Carlos O'Donell
2003-07-28 17:45 ` Matthew Wilcox
2003-07-28 19:04 ` Carlos O'Donell
2003-07-28 19:14 ` Matthew Wilcox
2003-07-28 21:10 ` Richard Hirst
2003-07-29 17:50 ` Carlos O'Donell
2003-07-29 18:55 ` Grant Grundler
2003-07-29 21:06 ` Richard Hirst
2003-07-29 23:36 ` Carlos O'Donell
2003-07-30 16:37 ` Thibaut VARENE
2003-07-29 23:38 ` Carlos O'Donell
2003-07-29 18:51 ` Grant Grundler [this message]
2003-07-27 20:43 ` Michael S.Zick
2003-07-28 20:30 ` Randolph Chung
2003-07-28 20:37 ` Matthew Wilcox
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