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From: James Bottomley <James.Bottomley@SteelEye.com>
To: John David Anglin <dave@hiauly1.hia.nrc.ca>
Cc: parisc-linux@lists.parisc-linux.org
Subject: Re: [parisc-linux] [PATCH] timer_interrupt and gettimeoffset.
Date: Mon, 04 Sep 2006 12:23:56 -0500	[thread overview]
Message-ID: <1157390636.3513.21.camel@mulgrave.il.steeleye.com> (raw)
In-Reply-To: <200609041657.k84GvPht025978@hiauly1.hia.nrc.ca>

On Mon, 2006-09-04 at 12:57 -0400, John David Anglin wrote:
> There needs to be a check to ensure that the code has enough time
> to set cr16 with the new compare time before the counter passes this
> value.  If it misses, the counter will wrap.  This probably doesn't
> need to be a full half tick if it's desireable to avoid negative
> offsets.

Exactly!

> In my mind, it's important to ensure that timer interrupts are not
> disabled for long periods.  If that's not possible, we could go back
> to 100 Hz.  However, I've been using 1000 Hz in an embedded project
> using a small 8-bit micro running at 40 MHz.  So, I think 1000 Hz
> should be possible on most PA processors.

Well ... I'm not sure about the rest of the PA world.  It's certainly
not possible on ioz (or any other pa8800).  According to my benchmarks,
the cache flush IPI takes 47ms to execute.  However, the pa8800 has such
a huge cache, it might not take this long on the other PA boxes.

James


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  reply	other threads:[~2006-09-04 17:23 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-08-30 16:38 Re:[parisc-linux] [PATCH] timer_interrupt and gettimeoffset Joel Soete
2006-08-30 16:52 ` [parisc-linux] " Grant Grundler
2006-08-30 20:23   ` Carlos O'Donell
2006-09-02 15:52     ` James Bottomley
2006-09-03 15:00       ` Carlos O'Donell
2006-09-03 15:17         ` James Bottomley
2006-09-03 16:14         ` James Bottomley
2006-09-03 19:31           ` Grant Grundler
2006-09-04 15:51             ` James Bottomley
2006-09-04 16:57               ` John David Anglin
2006-09-04 17:23                 ` James Bottomley [this message]
2006-09-04 19:12                   ` John David Anglin
2006-09-04 21:21                 ` Grant Grundler
2006-09-04 22:47                   ` James Bottomley
2006-09-04 23:52                     ` John David Anglin
2006-09-05  5:12                       ` Grant Grundler
2006-09-05 15:53                         ` James Bottomley
2006-09-05 22:49                           ` Grant Grundler
2006-09-05 22:59                             ` James Bottomley
2006-09-05 23:41                             ` John David Anglin
2006-09-06  0:24                         ` John David Anglin
2006-09-03 19:38       ` Grant Grundler
2006-09-03 19:59         ` John David Anglin
2006-09-04  0:09           ` Grant Grundler
2006-09-04  0:58             ` John David Anglin
2006-09-04  3:51             ` John David Anglin
2006-09-04 15:49         ` James Bottomley
     [not found] <44FDE867.3090204@scarlet.be>
2006-09-05 21:35 ` John David Anglin
  -- strict thread matches above, loose matches on Subject: below --
2006-08-30  4:48 Carlos O'Donell
2006-08-31  6:53 ` Grant Grundler
2006-08-31 18:52   ` Carlos O'Donell
2006-08-31 21:46     ` Grant Grundler
2006-09-03 14:54       ` Carlos O'Donell
2006-09-03 19:55         ` Grant Grundler
2006-09-03 20:29           ` James Bottomley
2006-09-03 20:30           ` Carlos O'Donell
2006-09-03 21:22             ` John David Anglin
2006-09-01 22:48   ` Grant Grundler
2006-09-01 22:59     ` Grant Grundler

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