I recently bought a used Vaio VPCW12J1E netbook. If you’re thinking of getting one, I highly recommend Lubuntu. It runs incredibly smoothly, with everything working flawlessly right away. It’s amazing how little memory it uses compared to resource-heavy software like Android.
The netbook came with Windows 7 Starter, which was sluggish due to pre-installed bloatware. Surprisingly, Windows identified my processor as dual-core. I thought most netbooks from 2009, especially this model, had single-core processors.
Windows Device Manager:
Windows Task Manager:
However, Lubuntu’s Task Manager (lxtaskmanager) shows a single core, which I found strange:
One of the screenshots reveals it’s an Atom N280, which Wikipedia tells confirms is single-core. What’s going on? I discovered the answer in a forum: Hyper-threading (HTT)!
Hyper-threading This brought back memories from 2002 when I was deep into hardware. Back then, “Virtual MultiProcessor” was the hot topic (alongside the Itanium). Multi-core processors later became widespread, and I wrongly assumed Hyper-threading faded away.
In simple terms, Hyper-threading duplicates certain units within a processor core, creating a limited form of multiprocessing. The operating system sees two cores and schedules two threads simultaneously. Depending on the instructions and processor state, a degree of parallelism occurs.
This reminded me of almost-forgotten concepts like Processor Pipeline and Superscalar processors. Superscalar and Hyper-threading share similarities by duplicating functional units for parallelism. However, This wikipedia entry clarifies that superscalar aims for parallelism within a single thread, transparent to the OS. In contrast, Hyper-threading targets parallelism between threads, requiring OS involvement.
Lubuntu’s single-core display made me question if Hyper-threading was enabled. I checked using:
sudo dmidecode
“status: Populated, Enabled” confirmed HTT was on.
Running top and pressing “1” to list processors (Cpu0 and Cpu1):
This was perplexing. While Linux showing one processor due to HTT’s limitations would make sense, top showing two while the Task Manager shows one is confusing.
