Re: 5.3-RELEASE: WARNING - WRITE_DMA interrupt timout

Poul-Henning Kamp wrote:
> In message <4195D903.2090801_at_DeepCore.dk>, =?ISO-8859-1?Q?S=F8ren_Schmidt?= wri
> tes:
> 
>>Zoltan Frombach wrote:
>>
>>>This is still an issue for me. Please read this post of mine:
>>>http://lists.freebsd.org/pipermail/freebsd-stable/2004-November/009420.html
>>>
>>>Can anyone help? I would gladely install test patches to track this 
>>>problem down. My system is 5.3-R. And the WRITE_DMA warning happens at 
>>>least twice a day, it is so predictable. With thanks,
>>
>>Hmmm, that warning is issued from ATA when requests has been returned to 
>>the systems bio_taskqueue but the system hasn't finished them within the 
>>timeout. Now this is an indication of the system being unresponsive 
>>already at that point, or at least that was the idea.
>>It has nothing to do with a bad drive, since the interrupt was seen the 
>>drive has finished the request it was asked, its the layers above ATA 
>>that doesn't respond to the request beeing returned as finished.
> 
> It is not really the task of the ata driver to fail requests at that
> time.   How long is the timeout anyway ?

Oh, ATA doesn't fail them, it just yells that the request hasn't been 
finished yet by the upper layers, it doesn't do anything to the request.

Timeout is 5 secs, which is a pretty long time in this context IMHO..

However, if it can take that long time to get data pushed up the chain, 
it might also explain some of the reduced I/O performance reported ?

-- 

-Søren