Date: Thu, 26 Jun 1997 16:25:45 +0100 (BST) From: Mr M P Searle <csubl@csv.warwick.ac.uk> To: root@counterintelligence.cdrom.com (0000-Administrator) Cc: questions@freebsd.org Subject: Re: FreeBSD Info Message-ID: <6699.199706261525@amaretto.csv.warwick.ac.uk> In-Reply-To: <Pine.BSF.3.96.970625194147.608A-100000@counterintelligence.cdrom.com> from 0000-Administrator at "Jun 25, 97 07:50:36 pm"
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> > Is there a FreeBSD system call or better yet a device that can be > opened > (/dev/io just allows the process to directly do io) and read/write to the > io ports. I need to port some software from linux which to my own disgust > uses inb and outb macros (which are defined in some standard .h include > file there) for controlling a analog io board that has no driver. After I > used the io ports I found out that there was a /dev/port device that can > be opened and read/write to a the file pointer which corresponds to an io > port, anyway with the exception of writing a kernel driver (i really don't > have the patience for that what can I do) also is there some kind of > documentation I can get on ther kernel - particularily it looks like (from > calling usleep(1) in a loop that the system timer runs 50-100 ticks > /second I want to increase this to like 1000-4000 if that is safe (and > won't annoyingly screw up the date/time) > Well, I've increased the system timer from 100 to 1000 Hz (by including options HZ=1000 in the config file) - there's no measurable increase in overhead time on a Pentium but it does mess some things up. (top and similar utilities measuring CPU time etc - not the system clock itself.) It may be that recompiling these utilities with HZ=1000 solves the problem, I'd not tried anything like this. Of course, YMMV as I've not actually looked at exactly what HZ does in the kernel.
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