You are currently on IBM Systems Media’s archival website. Click here to view our new website.

POWER > Business Strategy > Competitive Advantage

The Compelling Case for SMT8

Timothy J. Reynolds, SMT8
Illustration by Timothy J. Reynolds

Imagine yourself in a drive-through bank with two lanes. There’s one teller, and she’s helping the customer in the lane next to you. That customer asks a question that requires the manager’s help, so during the downtime, the teller assists you instead. Unfortunately your request will take some time to handle, too. So everyone behind has to wait.

Now imagine that same drive-through with eight lanes versus two. As you and the other customer are waiting, the teller continues to do her job. Several customers pull into the additional lanes, and the teller assists them one by one. It takes several minutes for your problem to be resolved, but the teller stays busy the whole time.

On average, SMT8 can bring a cost savings of up to 50%

When it comes to efficiency, eight lanes are better than two—both in the real world and the virtual world. Because of its simultaneous multithreading (SMT) capabilities, that kind of efficiency distinguishes IBM POWER8* technology from its competitors. If you’re looking for better performance with greater cost savings, the “eight-lane solution” is worth considering.

Seeing Is Believing

When you’re waiting in line in everyday life, minutes can seem like hours. Similarly, when your processing core is waiting for data on an everyday task, milliseconds can seem like forever. In today’s big data world, latency is the enemy.

In response, IBM engineers developed SMT based on something they learned in performance testing, explains Randy Rose, consulting software engineer in IBM’s Competitive Project Office. “When the core looked like it was doing something, they found that there’s actually a lot of idle time. That’s because as work was coming into the processor core, it had to wait for databases’ responses or other information, and that caused latency,” he says.

Early on, those engineers discovered that if they can enable multiple dispatchable units of work to occur—to be available to the core all the time—then when one thread is latent, the core can execute a task on a different thread. SMT allows for separate instruction streams, or threads, to run concurrently on the same physical socket, or processor core.

With the launch of the POWER8 processor last summer, IBM technology advanced from four threads to eight threads per core. And with eight threads, the odds are simply in your favor. Even when one of those threads is idle, seven others are in queue and ready to work.

Eve Daniels is a Minneapolis-based freelance writer.



2019 Solutions Edition

A Comprehensive Online Buyer's Guide to Solutions, Services and Education.


5 IBM i Architectural Principles Drive Business Innovation


How the API economy is changing business

IBM Systems Magazine Subscribe Box Read Now Link Subscribe Now Link iPad App Google Play Store