Re: [Beowulf] Hyperthreading and 'OS jitter'

2017-08-01 Thread Christopher Samuel
On 02/08/17 13:37, Evan Burness wrote: > Thanks for the history lessons, Chris! Very interesting indeed. My pleasure, to add to the history here's a paper from the APAC'05 conference 12 years ago that details how the then APAC (now NCI) set up their SGI Altix cluster, including a discussion on cp

Re: [Beowulf] Hyperthreading and 'OS jitter'

2017-08-01 Thread Evan Burness
Thanks for the history lessons, Chris! Very interesting indeed. Would be interesting to take it a step further and measure what the impacts (good, bad, or otherwise) of picking a specific core on a given CPU uArch layout for the OS. Cheers, Evan On Tue, Aug 1, 2017 at 10:32 PM, Christopher Sam

Re: [Beowulf] Hyperthreading and 'OS jitter'

2017-08-01 Thread Christopher Samuel
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 f