Direct Cache Access

From Intel Application Note 485, "Intel Processor Identification and the CPUID Instruction", section 3.1.10:

When EAX is initialized to a value of 9, the CPUID instruction returns DCA information in the EAX, EBX, ECX and EDX registers:

• EAX: Value of PLATFORM_DCA_CAP MSR Bits [31:0] (Offset 1F8h)
• EBX: Reserved
• ECX: Reserved
• EDX: Reserved

I've got a list of DCA-enabled NICs.

DCA requires both hardware and software support. Its successor, DDIO, does not.

See Also

• "Direct Cache Access for High Bandwidth Network I/O"
• "TCP Onloading for Data Center Severs"
• "Analyzing NIC Overheads in Network-Intensive Workloads"