TTY task group scheduling

Garrett Cooper gcooper at
Fri Nov 19 00:00:00 UTC 2010

On Thu, Nov 18, 2010 at 3:12 PM, Steve Kargl
<sgk at> wrote:
> On Thu, Nov 18, 2010 at 10:59:43PM +0000, Alexander Best wrote:
>> well i did exactly what they did in the video. watch a 1080p video and move
>> the output window around while compiling the kernel.
> It is trivial to bring ULE to its knees.  If you
> have N cores then all you need is N+1 cpu intensive
> task.  The issue has been known for a few years.


I/O intensive tasks don't help either though. Things tend to get
choppy whenever I'm doing something like update from svn and doing
something a bit more interactive like use firefox (and scroll... for
instance gmail seems to be a pig in this area -- heh), vlc is a little
less painful, etc.

I wonder if the issue isn't necessarily tasks but more or less
locking. firefox uses a lot of threads and file based mutexes
according to what I've seen with top and ps (please correct me if I'm

firefox also has a tendency with the nvidia-driver (I know... blobs
are bad) to produce funky artifacts on the screen (again, when
scrolling on gmail, dealing with flash, etc) or certain bits don't
redraw properly (text when scrolling ends up ghosting on multiple
lines until I force a redraw with the cursor or by scrolling back over
that section of text).

I'm sure there are a lot of performance issues within FreeBSD and
opensource desktop software that needs to be properly worked out on a
case by case basis, so I think that writing everything off as awesome
and working better with one magic patch is unlikely. Besides, Linux
has a more complicated scheduler than FreeBSD does.



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