Re: [PATCH 0/8] git pull request for tip/tracing/core

From: Kenji Kaneshige
Date: Wed Feb 11 2009 - 21:39:57 EST


Luck, Tony wrote:
>>> Before we go and make the change, Peter brought up a good point on IRC. Is
>>> there any reason that ia64 needs 1 << 14 IRQs? That's 16384!
>>>
>>> Perhaps the better solution wolud be (if possible), to simply lower the
>>> number of bits.
>> i'm the wrong person to be asked about that. (Cc:-ed the right people)
>
> People build some pretty big systems on ia64. SGI's largest has 4096
> cpus ... so 16384 IRQs is only 4 per cpu. That doesn't sound like very
> many to me.
>
> Fujitsu added the vector domain support for ia64 to get around the shortage
> of IRQs for large machines. Added them to the Cc: list to see if they have
> comments on how many IRQs are needed.
>

The 1024 IRQs are enough for GSIs on our maximum configuration. But
if the devices are MSI/MSI-X capable, it could be more than 1024.

Thanks,
Kenji Kaneshige


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