Re: SMP Support

Thanks for your prompt reply.

I am really looking for answers to the following questions:

1.  Is anyone currently working on SMP for AMD64?
2.  Is anyone currently working on SMP for EMT64?
3.  If so, who should I contact so I can offer assistance?

Thanks,
MikeE

On 6/9/06, R. Tyler Ballance <[email protected]> wrote:
>
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> This topic came up yesterday in #l4bsd on freenode, so I'll paste the
> transcript from the general "gist" of the conversation
> - ---------------------
> [11:12a] rtyler|intel: benno: how does Iguana (and in turn N1
> pistachio) handle SMP?
>
> [ snipped intermediate conversation ]
>
> [6:28p] benno​​: rtyler|intel: umm, it handles it just
> fine
> [6:38p] froody left the chat room. (Read error: 110 (Connection
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> [6:41p] ggonzahome left the chat room. (Read error: 113 (No route to
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> [6:56p] rtyler|intel​​: benno: I have no doubt about that,
> it's more of a question of how Iguana handles threads and memory in a
> multi-processor environment
> [6:57p] benno​​: how exactly do you mean? on smp
> iguana will give you the option of starting threads on different CPUs
> [6:57p] benno: iguana itself will stay single threaded
> [6:58p] benno: (as most of its operations would require holding a
> lock anyway, using IPC as the syncronising method is basically good
> enough..)
> [6:58p] rtyler|intel​​: benno: I guess just related to
> how FreeBSD does things (SMPng is my basis for any of this knowledge
> [6:58p] benno​​: no idea how freebsd does things
> [6:58p] rtyler|intel​​: i.e. 4.xx had the giant lock,
> and SMPng has brought fine-grained locking to 5.xx and 6.xx
> [6:59p] benno​​: right, iguana doesn't have fine
> grained locking, its single threadedness is basically a giant lock
> [6:59p] benno: but, you don't really call iguana nearly as often as
> you would call the bsd kernel
> [6:59p] benno: so it isn't clear that fine-grained locking would
> actually buy you anything (and in fact could have worse performance)
> [6:59p] rtyler|intel​​: but then what about services
> that it serves? do they share the same giant locking mechanism, in
> regards to the threading that iguana provides
> [7:00p] benno​​: well each server running on top of
> iguana can implement the policy it sees best
> [7:00p] benno: but really for most of them, the services then
> selves are fine grained
> [7:00p] benno: so each of these having a giant lock is kind of the
> same as having fine grained locks in a traditional kernel
> [7:01p] benno: well, not fine grained, probably coarse grained, but
> its not like the giant lock
> [7:01p] rtyler|intel​​: benno: I guess where i'm
> losing the train of thought is in that Iguana essentially operates as
> a giant lock, and provides threading to it's services, as to how
> those iguana services would run atop SMP systems
> [7:02p] benno​​: .. i need a whiteboard...
> [7:02p] benno: it is really L4 providing the smp support
> [7:02p] benno: it provides mechanisms to let you start threads and
> different CPUs
> [7:02p] benno: and migrate threads between different cpus
> - -------------------------------------------
>
>
> Hope that clears things up :)
>
> Cheers,
>
> - -R. Tyler Ballance
>
> On Jun 9, 2006, at 10:32 AM, Michael Emswiler wrote:
>
> > I am interested in Multiprocessor Support in Pistachio.
> >
> > I was wondering if anyone could point me to a link where i could
> > find current status on SMP support and what's in-progress?
> >
> > I am primarily interested in EMT64 and AMD64.
> >
> > Thanks,
> > MikeE
> >
> >
>
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