Understanding the Experiment ETA#

The ETA (Estimated Time of Arrival) endpoint predicts how much time remains for an experiment section to finish. It is available at:

GET /v4/experiments/{expid}/eta?section=SIM

The section query parameter is optional and defaults to SIM.

How the estimation works#

The ETA is based on the average runtime of already completed chunks:

  1. Jobs are grouped in chunks.

  2. For each chunk where all the jobs are completed, the chunk runtime is calculated as the difference between the latest finish time and the earliest start time of its jobs.

  3. These runtimes of all completed chunks are averaged.

  4. The result is multiplied by the number of remaining chunks.

For each completed chunk:
  runtime = max(finish) - min(start)

avg_runtime = average(runtime of all completed chunks)
remaining   = total_chunks - completed_chunks

eta = avg_runtime × remaining

Requisites#

The ETA estimation can only be computed if the experiment:

  1. Has at least one completed chunk. If not, the ETA will be returned as null.

  2. The section specified in the query parameter (or the default SIM) is defined with RUNNING: chunk.

Example#

An experiment with 5 SIM chunks configured with RUNNING: chunk:

exp:
  SIM:
    RUNNING: chunk
    NUMCHUNKS: 5
    CHUNKSIZE: 1
    CHUNKSIZEUNIT: year

After some time running, 2 chunks are completed, each taking about 2400 seconds to finish. The ETA would be:

avg_runtime = (2400 + 2400) / 2 = 2400 seconds
remaining   = 5 - 2 = 3 chunks
eta         = 2400 × 3 = 7200 seconds (2 hours)

API response:

{
  "eta_seconds": 7200.0,
  "chunks_total": 5,
  "chunks_remaining": 3,
  "avg_runtime_per_chunk_seconds": 2400.0
}