On Oct 24, 2014, at 12:06 PM, Andriy Gapon <a...@freebsd.org> wrote:

On 24/10/2014 21:39, Rui Paulo wrote:
Author: rpaulo
Date: Fri Oct 24 18:39:15 2014
New Revision: 273598
URL: https://svnweb.freebsd.org/changeset/base/273598

Log:
HPET: create /dev/hpetN as a way to access HPET from userland.

In some cases, TSC is broken and special applications might benefit
from memory mapping HPET and reading the registers to count time.
Most often the main HPET counter is 32-bit only[1], so this only gives
the application a 300 second window based on the default HPET
interval.
Other applications, such as Intel's DPDK, expect /dev/hpet to be
present and use it to count time as well.

Does this device attempt to play nice with eventtimer infrastructure that may
use the same timer?
 
No.  That's up to the userland applications and that's why I implemented the 
read-only restriction.
_______________________________________________
svn-src-head@freebsd.org mailing list
http://lists.freebsd.org/mailman/listinfo/svn-src-head
To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"

Reply via email to