On Thu, Feb 14, 2013 at 10:29:11AM +1300, Andrew Lindesay wrote:
I have been working on a small Haiku application for a while. A first
thing the user does with the application is to install some data. The
data needs to be processed and this processing takes a while and is a
bit disk-IO intensive. For this reason, I put up a progress bar so the
user can see something is happening. Unfortunately, the heavy disk-IO
seems to render the 'GUI' unresponsive; even the mouse-pointer freezes.
(meanwhile; another person has checked and the problem doesn't seem to
be happening on real hardware; just on virtual hardware - VirtualBox.)
To demonstrate the problem, I have built a small Haiku application with
just this problem distilled out. You can get this from;
http://www.silvereye.co.nz/tmp/maketrouble-1.0.0.tgz
I'd like to know if there's anything that can be done in Haiku to better
handle this in a future release or is there anything that I should be
doing differently in my application to better handle this?
I did a quick check with the above source, and yes, it happens
-- *if* you have only a single processor. On my 4-processor machine
I normally don't see it, but if I turn off 3 of them I get a display freeze
while the disk is being accessed.
I suspect this is the same 'priority inversion' problem that has been
bugging a number of us! It really shouldn't happen, but there may not
be much you can do about it until the glitch is fixed. (It is being worked
on -- still, I hope!) Maybe just a very short pause between I/O would
help without slowing things too much
-- Pete --
