- Jul 28, 2019
SMT has some pros and cons like any other tech. Please do not talk only. But give me a proof that more than 50% of servers runs with SMT OFF today. Give numbers, links...Why would Amazon care if SMT is Off or On with respect to software licensing costs? All they have to provide is the VM instance. Depending on what software foundation they're using, they aren't seeing any higher licensing costs per thread over per core. Its the user of the iron that's got to figure out what's best for them. If I'm throwing a software package on the cloud that I have to pay "per-thread" licensing for, then all I care about is what cloud has the best performance per thread and per dollar of CPU time that works with my licensing model. If I'm hosting my own server, and I'm paying for a DB package that is licensed by the thread, then I'm going to be looking for the solution that gives me the lowest cost of performance that can fit in my existing footprint. That's a complicate calculus as rack space is finite, cooling costs money, and per thread licensing can be quite expensive. Its not impossible that it makes more sense to get more physical cores in more physical systems because my per thread licensing is crazy high, and I better maximize the performance of each clock cycle that I have to license.
If I'm just hosting iron for other people, then all I have to worry about is my hypervisor, uptime management, and load balancing among systems while providing the highest value per vCPU minute that I offer. SMT makes sense for me.