[ECOS] Changing system timer resolution

[Grant Edwards <grante at visi dot com>]

I've gotten repeated requests from customers for different
(generally smaller) system timer resolutions.  Changing the
timer resolution is easy enough, but doing so breaks things
things since a lot of application level code (system tests, TCP
stack, DHCP task, etc.) depends on the assumption that a system
timer tick is 10ms.  [This assumption seems like a fairly
fundamental flaw for RTOS application code.]

It would be awfully nice if there were a simple way for an
application to determine the system timer tick resolution (e.g.
macros/functions to convert back and forth between
seconds<->ticks and ms<->ticks).  I know this information is
available, but it's buried pretty deeply and is difficult to
use.

Things like TCP and DHCP could then be written so that they
work with any system tick resolution.

If there were macros to convert between "real-world" time and
system ticks, how many places would those need to be inserted
for an eCos system to "just work" when the system timer
resolution is changed?

Would a change like this make it into the standard source tree?

If not, I don't think I want to fork my own version and have to
support it ad inifinitum -- I'll just have to tell those
customers they're out of luck if they don't like 10ms timer
ticks.

-- 
Grant Edwards
grante@visi.com