Interrupt hick ups

Martin Costabel costabel at
Sat Jun 17 03:27:46 EST 2000

"Timothy A. Seufert" wrote:

> Have you made sure your HD is set up for DMA, etc.?  For example, do
> "hdparm -d1 -u1 -m16 -p4 /dev/hda" and then run the -t throughput
> test.  (Use the man pages to make sure those are sane options, that's
> all from memory.)
> I remember similar fluctuation in 2.2.x as automatic negotiation of
> DMA and so forth was first put in then taken out of the IDE driver.
> Also, to make sure buffers get flushed before a test (for repeatable
> results) you should do hdparm -Tt, not just hdparm -t.

Yes, I did all this, except the -d1 bit which doesn't do anything on my
old drive. The numbers I gave were the maximum I could get with any kind
of tweaking.

Anyway, I am not really complaining (there are far more serious bugs in
-ac16), I guess it was just something too nice to stay for real.


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