The Multicore Era Over the past ~15 years, server processors from Intel and AMD have evolved from the early quad-core processors to the current monsters with over 50 cores per socket. The memory subsystems have grown at similar rates, from 3-4 DRAM channels at 1.333 GT/s transfer rates to 8-12… read more
Computer Hardware
“Memory directories” in Intel processors
One of the (many) minimally documented features of recent Intel processor implementations is the “memory directory”. This is used in multi-socket systems to reduce cache coherence traffic between sockets. I have referred to this in various presentations as: “A Memory Directory is one or more bits per cache line… read more
The evolution of single-core bandwidth in multicore processors
The primary metric for memory bandwidth in multicore processors is that maximum sustained performance when using many cores. For most high-end processors these values have remained in the range of 75% to 85% of the peak DRAM bandwidth of the system over the past 15-20 years — an amazing accomplishment… read more