On Mon, Apr 28, 2003 at 08:45:49AM +1000, Paul Mackerras wrote:

Fred Gray writes:

quoted

In both cases, ppc_irq_dispatch_handler is the "winner."  I'm not very familiar
with the kernel profiler, especially on the PowerPC, so I don't know whether
or not this is likely to be an artifact of piled-up timer interrupts.
Otherwise, it suggests that something dramatically inefficient is
happening in the interrupt handling chain, since it spends twice as much
time here as it does touching all of the outgoing data for the copy and
checksum.

ppc_irq_dispatch_handler is the first place where interrupts get
turned on in the interrupt handling path, so all the time spent saving
registers and finding out which interrupt occurred gets attributed to
it.

How many interrupts per second are you handling?  A 200MHz 604e isn't
a fast processor by today's standards.  Also, how fast is your memory
system?  I would be a little surprised if the memory controller could
deliver any more than about 100MB/s.

Hmmm, I get more than 100MB/s on my MVME2600 with a 200MHz 603e,
although not the half GB/s Motorola claims it is capable of. But a 604
should be a bit faster. The chipset is old (1997) but it was rather
fast when it came out, especially because the memory interface is 128
bits wide. This said, putting a gbit Ethernet (PMC module I suppose)
on it is stretching it a bit.

Is the 100Mb/s of the builtin interface too slow for you?

	Gabriel.

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