topic Hyper-Threading Processor in Intel® Moderncode for Parallel Architectures https://community.intel.com/t5/Intel-Moderncode-for-Parallel/Hyper-Threading-Processor/m-p/984278#M5803 Below table is obtained from Intel online training on How to detect an HT processor.<BR /><BR />It desible the register ebx bits to indentify the APIC IDs for all the processors.<BR />ebx Bit 31 30 29 28 27 26 25 24<BR />-----------------------------------<BR />APIC ID P P P P P P P/L P/L<BR />-----------------------------------<BR />1 <BR />processor X X X X X X X X<BR />-----------------------------------<BR />2 logical <BR />processors X X X X X X X L0/1<BR />-----------------------------------<BR />4 logical <BR />processors X X X X X X L3/4 L3/4<BR />--------------------------------------<BR /><BR />Referring to the table above, why is it 4 logical processors,at the bits 24 and 25 is L3/4 ? Why not at bit 24 and 25 respectively L0/1 and L2/3?<BR />What is L0/1, L3/4 represent? What does it mean?<BR /><BR />Thank you! Mon, 29 Sep 2003 13:22:56 GMT yaumeileng 2003-09-29T13:22:56Z Hyper-Threading Processor https://community.intel.com/t5/Intel-Moderncode-for-Parallel/Hyper-Threading-Processor/m-p/984278#M5803 Below table is obtained from Intel online training on How to detect an HT processor.<BR /><BR />It desible the register ebx bits to indentify the APIC IDs for all the processors.<BR />ebx Bit 31 30 29 28 27 26 25 24<BR />-----------------------------------<BR />APIC ID P P P P P P P/L P/L<BR />-----------------------------------<BR />1 <BR />processor X X X X X X X X<BR />-----------------------------------<BR />2 logical <BR />processors X X X X X X X L0/1<BR />-----------------------------------<BR />4 logical <BR />processors X X X X X X L3/4 L3/4<BR />--------------------------------------<BR /><BR />Referring to the table above, why is it 4 logical processors,at the bits 24 and 25 is L3/4 ? Why not at bit 24 and 25 respectively L0/1 and L2/3?<BR />What is L0/1, L3/4 represent? What does it mean?<BR /><BR />Thank you! Mon, 29 Sep 2003 13:22:56 GMT https://community.intel.com/t5/Intel-Moderncode-for-Parallel/Hyper-Threading-Processor/m-p/984278#M5803 yaumeileng 2003-09-29T13:22:56Z