Category: Hardware

John Cook has some thoughts on Google’s quantum supremacy announcement:

Google announced today that it has demonstrated “quantum supremacy,” i.e. that they have solved a problem on a quantum computer that could not be solved on a classical computer. Google says

Our machine performed the target computation in 200 seconds, and from measurements in our experiment we determined that it would take the world’s fastest supercomputer 10,000 years to produce a similar output.

IBM disputes this claim. They don’t dispute that Google has computed something with a quantum computer that would take a lot of conventional computing power, only that it “would take the world’s fastest supercomputer 10,000 years” to solve. IBM says it would take 2.5 days.

If you want to jump the gun but also stay on the Microsoft stack, the Q# programming language is open-source and you can run a simulator on your machine. Manning also has a Q# book in the works.

Glenn Berry takes a look at whether we want to invest in AMD’s latest server-grade processor:

On August 7, 2019, AMD finally unveiled their new 7nm EPYC 7002 Series of server processors, formerly code-named “Rome” at the AMD EPYC Horizon Event in San Francisco. This is the second generation EPYC server processor that uses the same Zen 2 architecture as the AMD Ryzen 3000 Series desktop processors. These new processors are socket compatible with the previous generation AMD EPYC 7001 Series processors, so they will work in existing model servers (with a BIOS update). Despite that, you will need a new model server to be able to use PCIe 4.0 support from the newer processors.

The AMD EPYC 7002 series includes 19 public launch SKUs that have anywhere from 8 to 64 physical cores, plus SMT, for twice the number of logical cores per processor. There are fourteen SKUs that will work in both one-socket and two-socket servers. There are also five less expensive processor SKUs (which have a “P” suffix) that only work in one-socket servers. This processor family has enough compute horsepower, memory bandwidth and capacity, and I/O bandwidth to support large server workloads on a single-socket server.

It certainly looks competitive. And that’s a great thing for consumers, even those who never make the switch, as it will force Intel to up its game.

Glenn Berry has an interesting post on why he’s seriously considering recommending AMD CPUs to people:

AMD claims a 15% Instructions Per Clock (IPC) increase between the desktop Zen+ and Zen 2 generations, and we are likely to see a similar increase between the previous AMD EPYC 7001 “Naples” and the AMD EPYC 7002 series processors.

So far, we don’t know the official base and turbo clock speeds, but there was a recent leak of partial specifications and pricing by a European retailer that listed max boost clock speeds of up to 3.4 GHz. We won’t know the actual single-threaded performance of these processors until they have been released and benchmarked by neutral third-party testers. I am optimistic that they will have higher single-threaded CPU performance than Intel Cascade Lake-SP processors.

I’ve always had a soft spot in my heart for AMD, so I’d love to see them come through with a serious competitor to Intel in the server space, for nostalgic reasons but also to make price more competitive and to make Intel get back on its game.

Joe Chang thinks about single-socket servers:

There is a mechanism by which we can significantly influence memory latency in a multi-processor (socket) server system, that being memory locality. But few applications actually make use of the NUMA APIs in this regard. Some hypervisors like VMware allow VMs to be created with cores and memory from the same node. What may not be appreciated, however, is that even local node memory on a multi-processor system has significantly higher latency than memory access on a (physical) single-socket system.

That the single processor system has low memory latency was interesting but non-actionable bit of knowledge, until recently. The widespread practice in IT world was to have the 2-way system as the baseline standard. Single socket systems were relegated to small business and turnkey solutions. From long ago to a few years ago, there was a valid basis for this, though the reasons changed over the years. When multi-core processors began to appear, the 2-way became much more powerful than necessary for many secondary applications. But this was also the time virtualization became popular, which gave new reason to continue the 2-way as baseline practice.

Joe points out that for a highly-used transactional system, the lower memory latency might make a single-socket server perform better than a multi-socket server.

Joe Chang wants us to think about socket counts:

It might seem that the 2-socket system continues to be a good choice, as two processors with an intermediate number of cores is less expensive than one processor with twice as many cores. An example is the Xeon Gold 6132 14-core versus the Xeon Platinum 8180 28-core processors. In addition, the two-socket system has twice the memory capacity and nominally twice as much memory bandwidth.

So, end of argument, right? Well, no.

Click through for his argument in favor of single-socket machines for OLTP systems.