Re: IDE drives and unmaskirq

From: Andre Hedrick (
Date: Mon Apr 24 2000 - 09:16:46 EST

On Mon, 24 Apr 2000, Andrew Morton wrote:

> I have done some measurements on this. The worst case interrupt
> blockage within the IDE code when using UDMA with DMA is 90 microseconds
> (500MHz CPU). When interrupts are unmasked this comes down to 32 usecs
> worst case. Compare this with the console code's 3,000 microseconds.
> More details at


> If you're concerned about latency you must knock off the peaks. With
> DMA, IDE is down in the noise floor. And that unmasking code is pretty
> scary stuff....
> >
> > PS: Andre: funny your E-Mail address :-)
> Not funny if you're stuck using dialup :-(

I have a static IP with lDSL..........go figure......

Andre Hedrick
The Linux ATA/IDE guy

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