I'm afraid you read too quickly and w/o attention to detail, please reread and pay special attention to the last paragraph. Especially to:
"IOMMU is present in all "real" AMD64 machines, but not the Intel clones. Unfortunately, OpenBSD support for IOMMU on the AMD machines is not quite ready for primetime (code exists, but "real life" has consorted against me finishing it)." On Sat, Feb 13, 2016 at 7:35 PM, Tinker <ti...@openmailbox.org> wrote: > Dear Karel, > > Thanks - wait - this post from 2006 you mentioned now, is it saying that > actually >32bit/>~3GB buffer cache IS SUPPORTED/WORKS on any AMD64 *with > IOMMU* support in the CPU, and was working all the time?? > > (That would mean that I misunderstood those references I posted in the > previous email because in actuality the 32bit/~3GB constraint only is in > certain usecases that is on non-IOMMU CPU:s.) > > Please clarify! > > > > So if so, any Intel processor with the "Intel® Virtualization Technology for > Directed I/O (VT-d)" feature such as for example this one > http://ark.intel.com/products/81061/ , or any of the CPU:s listed on > https://en.wikipedia.org/wiki/List_of_IOMMU-supporting_hardware , has that > support? > > Does the motherboard need specific support too as Wikipedia indicates - > though at least any Xeon server motherboard from the last 3-4 years must for > sure have it right? > > Thank you everyone for your excellent work with OpenBSD! > > Best regards, > Tinker > > [1] > David Mazieres linked to two docs in there, those are only on archive.org > now: > https://web.archive.org/web/20150814051509/http://www.intel.com/content/dam/w ww/public/us/en/documents/product-specifications/vt-directed-io-spec.pdf > https://web.archive.org/web/20081218031805/http://www.amd.com/us-en/assets/co ntent_type/white_papers_and_tech_docs/34434.pdf > > > > On 2016-02-14 01:15, Karel Gardas wrote: >> >> I think you would also like to investigate this one: >> http://www.undeadly.org/cgi?action=article&sid=20060614160000 >> >>> Some quite deep reading [1] taught me that at least quite recently, there >>> was a ~3GB cap on the buffer cache, independent of architecture and >>> system >>> RAM size.
