Messages in this thread | | | Date | Thu, 11 Nov 2010 23:59:55 +0300 | From | Cyrill Gorcunov <> | Subject | Re: [RFC -tip] x86, apic: Merge x2apic code |
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On Thu, Nov 11, 2010 at 12:44:17PM -0800, Suresh Siddha wrote: > On Wed, 2010-11-10 at 11:20 -0800, Cyrill Gorcunov wrote: > > Hi, while being at x2apic_x.c code I noted that files look similar to > > each other so I guessed may be we could merge them. As result -- > > this patch. > > BTW, as you noticed, x2apic cluster mode allows IPI's to be sent to > multiple cpu's (in the same cluster) at once. I was hoping sometime I > will do this to see if it helps in anything. > > So once we do that IPI code will look different.
yes, indeed, so enlight me a bit -- we have to map every cpu number from cpumask to apic-id, then figure out if it belongs to same cluster, collect such apic-ids and then send one ipi with one cluster and multiple apic-id bits as a destination, or I miss something and there _can't_ ever be the situation when first 16 cpus from cpumask belong to different clusters?
> > > So comments/complains are appreciated and what is more important -- if we need > > this patch at all. > > May be we can do the merge for most of them but leave IPI code as it is > (as that is also in the hot path). And may be while we are at this, we > should probably look at the x2apic cluster IPI bits now aswell. >
yes, probably. Though I think first we need to resolve situation with per-cluster IPIs.
> thanks, > suresh >
Cyrill
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