About the fifth time I've sent this ...
----- Begin Included Message -----
>From pnd Wed Feb 17 10:24:42 1999
Date: Wed, 17 Feb 1999 10:24:41 -0700 (MST)
From: pnd (Phil Daly)
To: [EMAIL PROTECTED]
Subject: clock units
Cc: pnd
Hi y'all,
First, I will be at the Linux World Expo and wondered if the RT-Linux
BoF session was still a go and where and when it was happening?
Second, I am re-posting this (dumb question) for the umpteenth time as
I'm not sure it ever got through.
Someone recently asked about RT_TICKS_PER_SEC and my question is
related and, I hope, an answer will clear my fuddled brain. I am
running RT-Linux (H) under 2.0.35 (RedHat) on a Gateway 4DX2-66V (as
a test-bed). In my /usr/include/asm/rt_time.h, the constant is defined as:
#define RT_TICKS_PER_SEC 1193180LL
Is this encoded in some way? If my machine is a 66 MHz, I would naively
expect 66,000,000 ticks per second of thereabouts (each having a duration
of about 15 ns). However, if I create a task to use the RTC interrupt and
set it to, say, 2 Hz there appear to be (about) 520000 RTIME ticks between
each task wake up i.e. the timestamps agree with 520k being half of 1193180.
This suggests that the minimum (useful) time is 840 ns and not some small
multiple of 15! Or can I schedule RT tasks with fractional periods? (Not tried
this, I must admit).
Any light you can shed would be appreciated. I have not read through the
RT-Linux code but maybe the answer lurks therein...
Confused of Tucson.
=================================================================+
Phil Daly, NOAO/AURA, 950 N. Cherry Avenue, Tucson AZ 85719, U S A
E-mail: [EMAIL PROTECTED] V-mail: (520) 318 8438 Fax: (520) 318 8360
----- End Included Message -----
----- End Included Message -----
--- [rtl] ---
To unsubscribe:
echo "unsubscribe rtl" | mail [EMAIL PROTECTED] OR
echo "unsubscribe rtl <Your_email>" | mail [EMAIL PROTECTED]
----
For more information on Real-Time Linux see:
http://www.rtlinux.org/~rtlinux/
