ULE/yielding patch for testing.

[Jeff Roberson]

On Sun, 7 Oct 2007, Marc Fonvieille wrote:

> On Sun, Oct 07, 2007 at 01:35:50AM -0700, Jeff Roberson wrote:
>>>> [...]
>>>> Not really when the slowness does not exist with 6.X.
>>>
>>> I have experienced certain websites causing firefox to slow down
>>> considerably.  When I mouse over firefox the mouse begins to jerk as well
>>> but when I move back away from firefox it seems fine again.  I suspected
>>> it was an x/firefox bug.
>>
>> Actually I double-checked this case with dailytech.com.  It seems to be
>> spending all of the cpu time in user-space in xwindows.  So it seems that
>> it is the new xwindows that has the problem.  If you watch the 'TIME' field
>> of top you can see that very little cpu time is attributed to firefox and
>> quite a lot to X windows.  So the windowing system is too busy to redraw
>> mouse events even if we are scheduling it well.
>>
>
> You mean Xorg 7.2 or 7.3 with -CURRENT?
> Currently I observe the problem with Xorg 7.2 or 7.3 under -CURRENT,
> when Xorg 7.2 with 6.2-STABLE is Ok (I did not try with Xorg 7.3 on
> -STABLE, but I'm quite sure I'll end to same result).
> On a completly different machine (a more recent one with a 2.8GHz
> Celeron), the problem could be less obvious cause of the machine speed
> but I can notice the difference between 6.2-STABLE and 7-CURRENT with
> any Xorg version.

Can you give a dozen lines of 'vmstat 1' output while rendering this page 
in 7.0 and 6.2?

Thanks,
Jeff

>
>> Jeff
>>
>>>
>>> Although I also sometimes observe mysql hanging for a period of a half
>>> second or so while running sysbench.  I wonder if we don't have a
>>> threading library bug?  I know I observed this prior to the thread_lock
>>> work so hopefully I didn't break it.
>>>
>
> I think a lot of people missed that problem cause they run fast
> machines.  For me it's very difficult to track down the issue cause I'm
> ignorant in these OS areas and the various logs and tools don't give
> obvious information.
>
> -- 
> Marc
>