Re: X becomes unresponsive with nvidia and hardlocks with gdb (was Re: X becomes unresponsive with nvidia / xscreensaver and desktop panics)

Garrett Cooper wrote:
> On Fri, Jan 9, 2009 at 5:05 PM, Garrett Cooper <yanefbsd_at_gmail.com> wrote:
>   
>> On Fri, Jan 9, 2009 at 2:05 PM, Garrett Cooper <yanefbsd_at_gmail.com> wrote:
>>     
>>> On Fri, Jan 9, 2009 at 1:40 PM, Doug Barton <dougb_at_freebsd.org> wrote:
>>>       
>>>> Garrett Cooper wrote:
>>>>         
>>>>> Thanks for the tips Doug -- I'll give them a shot of course...
>>>>>           
>>>> Glad I could help. The one thing I forgot to mention is to try the
>>>> nvidia-settings app if you have not already done so. There are various
>>>> things there that you can tweak that might yield better results.
>>>>
>>>> Doug
>>>>         
>>>    I did in fact set everything up via nvidia-settings. I'm running
>>> some stress tests right now to see whether or not I can simulate the
>>> issue -- it doesn't appear to be as straightforward as I thought..
>>> -Garrett
>>>
>>>       
>> I believe my actual problem with panicking is related to gdb, not X11.
>> So the actual problem is two-fold:
>>
>> - X11 livelocks, where I can login via ssh and kill .
>> - When I use gdb -p, it prints out the same message reported here:
>> <http://osdir.com/ml/gdb.bugs.discuss/2005-04/msg00043.html>. The only
>> thing is that if I press `y' on the first go-around, the machine
>> hardlocks on the first try with hitting `y'. If I hit `n' so gdb
>> coredumps, I can either go on my merry way, or go back to the
>> confirmation dialog. If I hit it again, it doesn't hardlock. It does
>> hardlock though, and for whatever reason my PC speaker beeps, and I
>> have to warm boot it. I haven't been able to get a kernel dump though,
>> so something else mysteriously is going on that I can't track.
>>
>> So, just to simplify:
>>
>> first_try := True
>>
>> while gdb is running:
>>    if prompt_for_coredump() and first_try is True:
>>        panic()
>>    first_try := False
>>
>> Thanks,
>> -Garrett
>>     
>
> Ok, I've been doing some more poking around this weekend, and here's
> what I discovered:
>
> - I've rebuilt my xorg-server a few times and it's still claiming that
> it was built with 7.1-RC2 -_-...
> - I can get the Xorg server to go full tilt by just compiling
> something, like buildworld, via an xterm.
>   
I also experienced this, but not only with the mentioned 'nv' driver,
also with 'vesa'. Compiling a kernel or making buildworld, even with no
-jX option, turns the box sometimes in a state of unresponseness. Mouse
jumping, no keyboard response, sometimes for more than a minute. This
happens on a FBSD 8.0-CUR/AMD64 UP box and it also happens on a FreeBSD
7.1-STABLE box (also amd64, 4 cores). But on SMP boxes I reralized that
the problem does not impact that harsh as seen on UP boxes.
We also had several P4 32bit machines with HTT enabled around, one of
them was built with FreeBSD 7.1-STABLE AND Xorg and I never realized the
bumpy X11, even when disabling HTT and running UP and Xorgs vesa driver.

Well, it also seems to make no difference whether I use USB2 stack (in
FreeBSD 8) or the old one.

> - I can't attach truss to Xorg, or the Xorg will livelock.
>
> Now, trying out the nv driver:
> - It constantly uses up ~20% CPU on one of my four cores. When I
> compile something it chews up ~50% CPU.
>   

The same on FreeBSD 8.0-CUR, recently built with a fresh install of xorg
out of the ports!
> - I can attach truss to Xorg, but it drags the CPU up to ~100%. Xorg
> was spending a LOT of time pinging socket data around, which makes me
> think that what the nvidia driver is doing is actually unrooting a
> performance issue with the IPC mechanism in Xorg, as nv suffers from
> the same thing, just on a less grand scale; mind you, I can get both
> of my screens up and running under nvidia at different resolutions --
> 1920x1200 and 1680 x 1050 -- but under nv I only get 2 displays setup
> at 1680 x 1050.
> - Detaching truss causes the livelock condition (again).
>
> Rebuilding xorg-server has proven to help so far. I did
> delete-old-files, and it appears that xorg-server may have been
> picking up some old libraries still.
>
> Let's see if this sticks or not...
>
> Cheers,
> -Garrett
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>   

Oliver