Allocation Reductions

Projects not using their allocation effectively in the first three quarters of the allocation year may have some of their allocation returned to the reserve pool of their respective DOE Office of Science Program to be redistributed to other projects.

The redistribution of time is required because many projects do not use their allocations early in the year, leading to a large aggregate build-up of unused time that can not possibly be used before the end of the year, given the size of the system and hours remaining in the year. 

For example, the table below shows the median project usage for AY2023.

The allocation reductions allow DOE program managers to strategically reallocate time to projects that can use it earlier in the year. NERSC does not allow exemptions to this policy. The removed time is returned to the DOE program managers who made the initial award for redistribution at their discretion.

We realize that not all projects will use their allocations at a steady pace throughout the year. Therefore, when projects apply for an allocation, they are asked to estimate their quarterly usage. Allocation reductions are made relative to those estimates. (If the aggregate estimates are too heavily backloaded, NERSC will work with users and program managers to address the situation early in the year.)

(ALCC, Director's Reserve, Exploratory, and Educational projects are exempt from this reduction. However, ALCC has its own allocation reduction scheme, and the Director's Reserve program may make reductions at NERSC's discretion.) 

Allocation Year 2024

The following schedule will be used for Allocation Year 2024 (which runs from January 17, 2024 through January 14, 2025).

We will be using the forecasted computer usage values entered in the AY 2024 ERCAP requests. If you selected "I plan to use resources consistently throughout the allocation year", then your quarterly usage was set to 25% usage per quarter. If you selected "My usage will vary throughout the allocation year", then we will use the percent of usage you entered for each quarter. 

On April 17, 2024:

• We will calculate the Expected Usage as: Expected_usage = initial_allocation*Q1_pct_in_ERCAP for Q1
• Then if the actual usage is less than the Expected usage, we will remove time using the formula: 
  • If usage<expected_usage, reduce by 0.5*(usage-expected_usage)
• For example:
  • If the Initial Allocation is 1000 Node hours and the Q1 % in ERCAP = 25%, then the Expected Usage = 250 Node hours
  • If the Actual Usage is only 50 Node hours, then the amount removed will be: 0.5 * (50 - 250) = 0.5 * (-200) = -100 Node Hours

This reduction scheme will apply to both CPU and GPU allocations, but handled separately (e.g., a project that has charged 10% of its CPU allocation but 20% of its GPU allocation, the amounts removed will be adjusted accordingly).

NERSC will accept requests for exemptions from the first quarter reductions only. Project Principal Investigators, PI Proxies or Project Resource Managers can request exemptions by creating a ticket at https://help.nersc.gov and include justification for the exemption. They must submit the request at least one week before the reductions are scheduled to take effect. 

On July 17, 2024:

• The calculation for the Expected Usage for the 2nd Quarter: initial_allocation*(Q1_pct_in_ERCAP + Q2_pct_in_ERCAP)
• Then if the actual usage is less than the Expected usage, we will remove time using the formula: 
  • If usage<expected_usage, reduce by 0.5*(usage-expected_usage)
• For example:
  • If the Initial Allocation is 1000 Node hours and the Q1 % in ERCAP = 25% and the Q2 % in ERCAP = 25%, then the Expected Usage = 500 Node hours
  • If the Actual Usage is only 100 Node hours, then the amount removed will be: 0.5 * (100 - 500) = 0.5 * (-400) = -200 Node Hours

On October 16, 2024:

• The calculation for the Expected Usage for the 3rd Quarter: initial_allocation*(Q1_pct_in_ERCAP + Q2_pct_in_ERCAP + Q3_pct_in_ERCAP)
• Then if the actual usage is less than the Expected usage, we will remove time using the formula: 
  • If usage<expected_usage, reduce by 0.5*(usage-expected_usage)
• For example:
  • If the Initial Allocation is 1000 Node hours and the Q1 % in ERCAP = 25% and the Q2 % in ERCAP = 25% and the Q3 % in ERCAP = 25%, then the Expected Usage = 750 Node hours
  • If the Actual Usage is only 150 Node hours, then the amount removed will be: 0.5 * (150 - 750) = 0.5 * (-600) = -300 Node Hours