5.3-RELEASE: WARNING - WRITE_DMA interrupt timout
Søren Schmidt
sos at DeepCore.dk
Sat Nov 13 02:01:20 PST 2004
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
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