SCHED_ULE on desktop system
Jeff Roberson
jroberson at chesapeake.net
Mon Sep 17 14:19:36 PDT 2007
On Mon, 17 Sep 2007, Roman Bogorodskiy wrote:
> Roman Bogorodskiy wrote:
>
>> Jeff Roberson wrote:
>>
>>> On Sun, 16 Sep 2007, Roman Bogorodskiy wrote:
>>>
>>>> Jeff Roberson wrote:
>>>>
>>>>> This is contrary to the experiences of many others. Can you send me your
>>>>> dmesg? There may be something about your particular hardware that is
>>>>> triggering a bug. ULE is definitely designed to be responsive on the
>>>>> desktop.
>>>>
>>>> Thanks for the quick answer!
>>>>
>>>> Here's my dmesg: http://people.freebsd.org/~novel/misc/dmesg.txt
>>>
>>> Roman,
>>>
>>> The enclosed patch helps things on my system, however, there are still some
>>> delays due to IO issues. Let me know if this helps.
>>
>> This patch seems to make my system react faster. However I need some
>> time to test it more carefully.
>
> It looks like it's not really so, it's still very slow under load. :(
Roman,
Can you please verify that you are not swapping. If you are, try the
patch that I sent. Otherwise, can you try getting KTR_SCHED output for
me? Put the following in your kernel config file:
options KTR
options KTR_COMPILE=KTR_SCHED
options KTR_MASK=KTR_SCHED
options KTR_ENTRIES=65536
Then run the load that exhibits the problem. compile, play a movie, etc.
wait for a particularly bad pause and then run the following:
sysctl debug.ktr.mask=0 && ktrdump -ct > out && sysctl
debug.ktr.mask=536870
It's best to have the command ready in a shell so you can run it in the
closest proximity to the incident. Then gzip the results and email them
to me.
On my system I'm not able to play a movie while running buildworld due to
long disk waits. However, if I use a dvd driver, mplayer and x
windows both get enough cpu time to play the movie skip free. So this is
not a cpu scheduler problem as such. IO scheduling does feel less
responsive than 6.x but I have not done a side by side comparison.
Jeff
>
>>> Thanks,
>>> Jeff
>>>
>>>>
>>>> Roman Bogorodskiy
>>>>
>>
>>
>> Roman Bogorodskiy
>
>
> Roman Bogorodskiy
>
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