From: "Guy G. Sotomayor, Jr." <ggs@shiresoft.com>
To: Dan Malek <dmalek@jlc.net>
Cc: Cort Dougan <cort@persephone.cs.nmt.edu>,
Troy Benjegerdes <hozer@drgw.net>,
linuxppc-dev@lists.linuxppc.org
Subject: Re: PReP RTC vs Decrementer accuracy...
Date: Thu, 10 Dec 1998 11:26:50 -0800 [thread overview]
Message-ID: <36702079.69588EB4@shiresoft.com> (raw)
In-Reply-To: 36700A9F.C1C99794@jlc.net
Dan Malek wrote:
>
> Guy G. Sotomayor, Jr. wrote:
>
> > Umm, but why are you keeping track of time with the decrementer?
>
> Because that is the way it was done when I first looked at the kernel
> a long time ago :-).
>
> > .....use the timebase to keep track of time and the decrementer
> > to deliver periodic interrupts?
>
> Excellent idea. I have started to implement this on an MPC8xx board,
> so I will let everyone know the results pretty quickly.
>
> It appears the TB is part of every PPC core. If anyone knows different
> please let me know.
>
I haven't looked into how the various Linux ports deal with time, but back
when I was doing microkernel work (for a large computer company with a 3
letter name) this is how we kept time since all of the processors we were
dealing with had a time base or its moral equivalent. This was necessary
since we didn't use the decrementer to deliver fixed period interrupts and
trying keep time from drifting would have been hard.
TTFN - Guy
[[ This message was sent via the linuxppc-dev mailing list. Replies are ]]
[[ not forced back to the list, so be sure to Cc linuxppc-dev if your ]]
[[ reply is of general interest. To unsubscribe from linuxppc-dev, send ]]
[[ the message 'unsubscribe' to linuxppc-dev-request@lists.linuxppc.org ]]
next prev parent reply other threads:[~1998-12-10 19:26 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
1998-12-07 12:31 USB, PCI and registers Benjamin Herrenschmidt
1998-12-07 21:02 ` PReP RTC vs Decrementer accuracy Troy Benjegerdes
1998-12-08 5:00 ` Cort Dougan
1998-12-08 20:32 ` Dan Malek
1998-12-08 23:52 ` Cort Dougan
1998-12-09 7:30 ` Troy Benjegerdes
1998-12-09 8:25 ` Cort Dougan
1998-12-09 23:52 ` Corey Minyard
1998-12-10 4:20 ` Corey Minyard
1998-12-10 5:48 ` Cort Dougan
1998-12-10 10:58 ` Geert Uytterhoeven
1998-12-10 16:00 ` Corey Minyard
1998-12-09 20:37 ` Dan Malek
1998-12-10 5:57 ` Guy G. Sotomayor, Jr.
1998-12-10 17:53 ` Dan Malek
1998-12-10 19:26 ` Guy G. Sotomayor, Jr. [this message]
1998-12-11 5:53 ` Dan Malek
1998-12-13 17:05 ` Gabriel Paubert
1998-12-14 6:45 ` Dan Malek
1998-12-15 20:12 ` Dan Malek
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=36702079.69588EB4@shiresoft.com \
--to=ggs@shiresoft.com \
--cc=cort@persephone.cs.nmt.edu \
--cc=dmalek@jlc.net \
--cc=hozer@drgw.net \
--cc=linuxppc-dev@lists.linuxppc.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).