[Beowulf] Hyperthreading and 'OS jitter'
samuel at unimelb.edu.au
Tue Aug 1 20:32:23 PDT 2017
On 26/07/17 00:31, Evan Burness wrote:
> If I recall correctly, IBM did just what you're describing with the
> BlueGene CPUs. I believe those were 18-core parts, with 2 of the cores
> being reserved to run the OS and as a buffer against jitter. That left a
> nice, neat power-of-2 amount of cores for compute tasks.
Close, but the 18 cores were for yield, with 1 core of running the
Compute Node Kernel (CNK) and 16 cores for the task that the CNK would
launch. The 18th was inaccessible.
But yes, I think SGI (RIP) pioneered this on Intel with their Altix
systems and was the reason they wrote the original cpuset code in the
Linux kernel so they could constrain a set of cores for the boot
services and the rest were there to run jobs on.
All the best,
Christopher Samuel Senior Systems Administrator
Melbourne Bioinformatics - The University of Melbourne
Email: samuel at unimelb.edu.au Phone: +61 (0)3 903 55545
More information about the Beowulf