Messages in this thread | | | Date | Thu, 6 Dec 2001 07:51:26 -0600 | From | "Florin Iucha" <> | Subject | Re: Adaptec-2920 eats too much cpu time when reading from the CD-ROM |
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On Thu, Dec 06, 2001 at 09:28:08AM +0000, Alan Cox wrote: > > I have recently purchased a Plextor 12x CD-RW and I have attached it to > > and Adaptec-2920 SCSI card. The card uses the "Future Domain Corp. TMC-18C30 > > [36C70]" chip. > > > > The problem I see: when reading from the CD-RW my system becomes very > > unresponsive and top reveals 90-95% of the time is spent on "system". > > My CPU is AMD K6-III/500MHz with 256 Mb RAM. > > I'd expect that. The 2920 is pretty old. It has no DMA channel and several > processes it must perform are polled not interrupt driven.
There is one interesting thing about it: when I write a CD, I write at 12x - that means 1800Kb/s, which is comparable with the reading speed of 2400Kb/s. But when writing, the system CPU usage is about 30%.
What could make the controller eat so much time when reading but not when writing?
Thanks, florin
PS. The patch fixes the "bad boy" message.
--
"If it's not broken, let's fix it till it is."
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