SGI also did a lot of scalability work in that time frame, as part of their migration from MIPS+Irix to Itanium+Linux. In the end they got Linux working on IIRC

SGI also did a lot of scalability work in that time frame, as part of their migration from MIPS+Irix to Itanium+Linux. In the end they got Linux working on IIRC up to 4096 processors.