Using ionice -c3 in f13: system seems less responsive than under f12

[John Pilkington]

On 26/11/10 08:46, Harald Hoyer wrote:
> Am 25.11.2010 14:30, schrieb John Pilkington:
>> Hi: My system spends a lot of its time processing video data, often
>> with not much numerical processing involved - just remuxing or making an
>> iso image. atop often shows disk activity above 90%. I do most of this
>> using ionice -c3, (ie 'idle' scheduling) which is supposed to reduce
>> impact on other tasks. The man page says "The impact of idle io
>> processes on normal system activity should be zero" and certainly
>> under f12 that seemed at least approximately true; but under f13
>> terminal response is often very sluggish when these tasks are running.
>> Using kde 4.5.3, scheduling elevator=deadline (as in f12).
>>
>> Am I expecting the right thing? Does anyone else see this?
>>
>> John P
>>
>
> maybe your processing is using CPU also?
>
Well, yes.  But the CPU-intensive parts seem ok; it's the parts that are 
essentially datastream shuffling that are having the most impact, and it 
seems more noticeable than it did in f12.  I've tried to arrange these 
to read and write on different spindles.  Maybe different tasks are 
having to be retrieved from disk, and that accounts for the delay, but I 
didn't think that was happening.  Swap doesn't appear to be active.

My initial reply didn't go to the list.  Sorry!