Another option might be to estimate lifetime cost (purchasing price +
average power consumption + maintenance) of each type of node and then
base multipliers on that. Not all workloads correlate well with linpack.
Many teaching institutions also give students some amount of core hours
per month to use as exploratory, usually trying to encourage parallelism
on more than one node by discounting short runs that make use of
multiple nodes.
On 6/21/19 11:17 PM, Prentice Bisbal wrote:
In this case, I would run LINPACK on each generation of node (either
the full node or just one core), and then somehow normalize
performance. I would recommend using the performance of a single core
of the slowest node as your basis for normalization so it has a
multiplier of 1, and then the newer systems would have a multiplier
greater than 1. Then you can take that multiplier and multiply it by
the number of cores in your different systems to get a final
multiplier for a while node, if needed.
Prentice
On 6/19/19 3:30 PM, Fulcomer, Samuel wrote:
(...and yes, the name is inspired by a certain OEM's software
licensing schemes...)
At Brown we run a ~400 node cluster containing nodes of multiple
architectures (Sandy/Ivy, Haswell/Broadwell, and Sky/Cascade)
purchased in some cases by University funds and in others by
investigator funding (~50:50). They all appear in the default SLURM
partition. We have 3 classes of SLURM users:
1. Exploratory - no-charge access to up to 16 cores
2. Priority - $750/quarter for access to up to 192 cores (and with a
GrpTRESRunMins=cpu limit). Each user has their own QoS
3. Condo - an investigator group who paid for nodes added to the
cluster. The group has its own QoS and SLURM Account. The QoS
allows use of the number of cores purchased and has a much higher
priority than the QoS' of the "priority" users.
The first problem with this scheme is that condo users who have
purchased the older hardware now have access to the newest without
penalty. In addition, we're encountering resistance to the idea of
turning off their hardware and terminating their condos (despite MOUs
stating a 5yr life). The pushback is the stated belief that the
hardware should run until it dies.
What I propose is a new TRES called a Processor Performance Unit
(PPU) that would be specified on the Node line in slurm.conf, and
used such that GrpTRES=ppu=N was calculated as the number of
allocated cores multiplied by their associated PPU numbers.
We could then assign a base PPU to the oldest hardware, say, "1" for
Sandy/Ivy and increase for later architectures based on performance
improvement. We'd set the condo QoS to GrpTRES=ppu=N*X+M*Y,..., where
N is the number of cores of the oldest architecture multiplied by the
configured PPU/core, X, and repeat for any newer nodes/cores the
investigator has purchased since.
The result is that the investigator group gets to run on an
approximation of the performance that they've purchased, rather on
the raw purchased core count.
Thoughts?
