Re: Poor performance of pthreads across cpu dies.
Re: Poor performance of pthreads across cpu dies.
- Subject: Re: Poor performance of pthreads across cpu dies.
- From: Terry Lambert <email@hidden>
- Date: Wed, 5 Sep 2007 13:32:20 -0700
On Sep 5, 2007, at 1:21 PM, Andrew Gallatin wrote:
Terry Lambert writes:
From my reading of things, the issue as to whether or not you can
target multiple CPUs with MSI has more to do with contiguous vs. non-
contiguous vector assignment (which means that it's not possible in
older Linux kernels). The MSI-X implementation overcomes this in
older Linux kernels due to independent configuration of message data
and address. BUT, if you are willing to perform contiguous
allocations, it's not a problem for MSI to do the same.
I'm not sure what linux kernels have to do with it.
The limitation is an old Linux one, according to Intel.
If you were to allocate 4 contiguous vectors, each vector could target
a different ID, and the set of vectors could be associated with a
single device.
The problem with
multiple messages in MSI is that all messages have the same message
address, but just different message data. Using the same message
address means that all interrupts will be delivered to the same
APIC, and hence to the same CPU. However, maybe this isn't a problem
on darwin/OSX, since all hardware interrupts are delivered to CPU 0
anyway...
I think you missed where Mike pointed out that delivery is not as
straight-forward as I initially said (I was mistaken, and Mike was
correct here).
-- Terry
_______________________________________________
Do not post admin requests to the list. They will be ignored.
Darwin-dev mailing list (email@hidden)
Help/Unsubscribe/Update your Subscription:
This email sent to email@hidden