Kevin Radloff wrote:
On 5/16/06, Alan Cox <[email protected]> wrote:
On Maw, 2006-05-16 at 11:33 -0400, Kevin Radloff wrote:
> However, I still have a problem with pata_pcmcia (that I actually
> experienced also with the ide-cs driver) where sustained reading or
> writing to the CF card spikes the CPU with nearly 100% system time.
That is normal. The PCMCIA devices don't support DMA. As a result of
this the processor has to fetch each byte itself over the ISA speed
PCMCIA bus link.
Hrm, as I recall that only started happening with ide-cs sometime in
the single digits of 2.6.x.. And note that it's only maxing out at
about 1.5MB/s. Should that saturate my laptop's 1.1GHz Pentium M
processor?
Doing data xfer using PIO rather than DMA definitely eats tons of CPU
cycles.
Jeff
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