Messages in this thread | | | Subject | Re: [patch] oprofile + ppc750cx perfmon | From | Benjamin Herrenschmidt <> | Date | 25 Mar 2003 10:45:02 +0100 |
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On Tue, 2003-03-25 at 09:57, Bryan Rittmeyer wrote:
> wow. inside of open_pic.c, I bet it's code like this > > while (openpic_read(addr) & OPENPIC_ACTIVITY); > > that's showing up.
That's interesting. You are raising again an old debate of wether to disable the IRQ during handling on openpic or not, I beleive we don't need to disable it on this PIC, but we do this for "safety" reasons.
In fact, I think our
openpic_ack_irq() should do something like
if (edge) openpic_eoi();
and our openpic_end_irq() something like
if (level) openpic_eoi();
Also, the fact that PIC access is slow is a generic "feature" of such chips, I also think we could actually be smarter and only soft-disable IRQs with a flag in the descriptor, and hard disable them if and only if they actually occur while disabled.
Ben.
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