Date: Thu, 17 Feb 2005 17:26:25 +0200 From: Petri Helenius <pete@he.iki.fi> To: John Baldwin <john@baldwin.cx> Cc: Joseph Koshy <joseph.koshy@gmail.com> Subject: Re: Logical CPU -> physical CPU conversion Message-ID: <4214B7A1.3010308@he.iki.fi> In-Reply-To: <d37cf8f1d4098a5ba19135ea7e18e6a9@baldwin.cx> References: <84dead7205021700272b4760f3@mail.gmail.com> <d37cf8f1d4098a5ba19135ea7e18e6a9@baldwin.cx>
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John Baldwin wrote: > > On Feb 17, 2005, at 3:27 AM, Joseph Koshy wrote: > > > For current Intel HTT CPUs, yes. Note that this might get tricky with > the dual core CPUs coming from both AMD and Intel in the not too > distant future as we don't know yet how they will enumerate the cores. > It may be that the cores "look" like HTT cores when they are actually > full cores, so I would try to abstract this in a way that you can use > different implementations for different CPUs to determine when a > logical CPU is a HTT CPU vs. a full core. Also, I imagine that even > with dual core Intel CPUs there is a chance that they might do HTT > inside each core, so that a single physical processor would have 2 > cores each with 2 HTT so a total of 4 logical CPUs from one piece of > silicon. > It would be logical to follow the documented convention; -quote- In future IA-32 processors supporting Hyper-Threading Technology that implement more than two logical processors per physical processor, the logical processor bit shown in Figure 7-5 will be expanded to a 2- or 3-bit field to allow each of the logical processors to be identified. The package ID and cluster ID fields will be shifted to the left accordingly. Also, the package ID may be expanded to more than 2 bits, requiring the cluster ID field to be shifted to the left. -quote- Petehelp
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