Re:AMD Tackles Coming “Chiplet” Revolution With New Chip Net...
by dragontamer on Sunday June 24, 2018 @04:44PM
(#17388300)
I'm not sure if SoC is breaking apart actually. I think chipbuilders are figuring out that its more efficient to combine some dies together at the package level.
Consider that EPYC is basically a miniturized multi-socket design. Infinity Fabric is really AMD's new protocol built on top of HyperTransport (multi-socket protocol from the past). Before, AMD used to support 8-sockets. But today, AMD stitches 4-chips together and only supports 2-sockets.
From a software perspective (ie: NUMA), EPYC x2 sockets looks like an 8-socket chip of old. In effect, AMD has miniturized the 4x-socket setup in the form of EPYC. And it has also miniturized the 2x socket setup in the form of Threadripper.
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These Threadripper / EPYC chips have the same downsides as all old 2x, 4x, and 8x NUMA designs of the past. High latency and poor communications between cores.
The thing is: the modern environment is a highly virtualized, highly independent set of systems. Running 8x NUMA efficiently today is as simple as spinning up 8x VMs, one for each NUMA node.
IIRC, people are finding that Intel's 28-core design is far more effective in say... unified Database performance. Intel's design has a true L3 cache which can be used by all 28-cores, while AMD's L3 cache is split between each die. 4x 8MB caches cannot function as a singular cache in a large-scale database application.
But there's enough situations (ie: VMs, multitasking, render farms) where AMD's NUMA + Infinity Fabric is good enough. And with prices anywhere from 1/4th to 1/2 the cost of Intel, AMD's chips these days are certainly worth considering.
Consider that EPYC is basically a miniturized multi-socket design. Infinity Fabric is really AMD's new protocol built on top of HyperTransport (multi-socket protocol from the past). Before, AMD used to support 8-sockets. But today, AMD stitches 4-chips together and only supports 2-sockets.
From a software perspective (ie: NUMA), EPYC x2 sockets looks like an 8-socket chip of old. In effect, AMD has miniturized the 4x-socket setup in the form of EPYC. And it has also miniturized the 2x socket setup in the form of Threadripper.
----------------------
These Threadripper / EPYC chips have the same downsides as all old 2x, 4x, and 8x NUMA designs of the past. High latency and poor communications between cores.
The thing is: the modern environment is a highly virtualized, highly independent set of systems. Running 8x NUMA efficiently today is as simple as spinning up 8x VMs, one for each NUMA node.
IIRC, people are finding that Intel's 28-core design is far more effective in say... unified Database performance. Intel's design has a true L3 cache which can be used by all 28-cores, while AMD's L3 cache is split between each die. 4x 8MB caches cannot function as a singular cache in a large-scale database application.
But there's enough situations (ie: VMs, multitasking, render farms) where AMD's NUMA + Infinity Fabric is good enough. And with prices anywhere from 1/4th to 1/2 the cost of Intel, AMD's chips these days are certainly worth considering.