ide-cs using 100% CPU
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----- Original Message -----
From: "Hamie" <[email protected]>
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Quoted 3 lines · Robert Hancock
It isn't that the CPU is doing so much work, it's mostly waiting. However
That was my point... While waiting, shouldn't the CPU be off doing something else? Like giving X some attention...
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with this type of PIO access, the CPU must do all the reads/writes from
the
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buffer and while doing this the CPU is blocked and cannot do anything
else.
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Or is the CF requirements such that it's spending it's time doing the actual reads & writes from the buffer, and it's the hardware inserting wait-states when it's being accessed?
That's basically what's happening, when the CPU does a write or a read of some data from the buffer, it has to wait for that to go all the way across the bus and to/from the card, meanwhile no other useful work can be done while it is waiting. As Alan Cox mentioned, having a hyperthreaded CPU helps tremendously in such cases, since the other "half" of the CPU can be doing useful work while the first half is blocked.