Skip to content

For juelich juwels infrastructure and model engineering teams

JUWELS GPU training stall: launch geometry or an earlier worker error?

Compare rank placement, assigned devices and the first exception from the selected JUWELS module. Keep device sharing and application parallelism distinct.

Replay one resolved incidentTry 30 days free

Free 30-day Team evaluation. No card or automatic subscription. Work email verification required.

Live diagnosis, no signup

Replay a resolved Juelich JUWELS workflow incident

Upload your log file. Review the selected evidence and masking, then run diagnosis. Keep the original log for any follow-up questions.

Before uploading, review cloud data handling and local options.

training_logs.txt
No log to hand? Try one:

Upload your log file. Large files are processed in your browser. Only selected evidence is submitted when you run diagnosis.

3 free diagnoses/day

Try Denpex for 30 days. FREE.

No credit card. No automatic subscription. See whether Denpex helps with an incident you already understand.

Start your free 30-day Team evaluation

Up to 50 diagnoses a day for 30 days. Verify your work email to activate an eligible company evaluation, then replay a resolved incident and compare the evidence and next steps with your team's confirmed cause.

Use your company email (e.g. alex@yourcompany.com). Eligible company domains can activate a free 30-day Team evaluation (up to 50 diagnoses/day) after email and domain checks, regardless of mail host. Uncertain domains can request review from support@denpex.com. Free local diagnoses remain available without an account.

What a useful evaluation should establish

Compare the first failure, quoted evidence and unresolved questions with an incident your team has already resolved. Begin with this question: Which module and GPUs did the job use? Only attribute a process, rank, device or recovery state when the submitted evidence establishes it.

Which module and GPUs did the job use?

Evidence to compare: Module, effective allocation and rank-to-device placement.

A system name alone cannot identify the execution environment. Preserve the assigned hardware and mapping before attributing a failure to a rank or device.

Was device sharing part of the launch?

Evidence to compare: Scheduler options, relevant MPS setting and application launch output.

Sharing configuration and process placement can affect how work reaches a GPU. Record those settings rather than interpreting utilization in isolation.

Which failure preceded the collective symptom?

Evidence to compare: The first worker traceback and corresponding host or transport events.

A waiting collective can reflect an earlier process failure. Require time alignment and identifiers before assigning a device, network or scheduler cause.

Use Denpex alongside your existing telemetry tools to investigate submitted incident evidence. With monitoring configured on a supported plan, detected failures can trigger alerts and an automatic diagnosis from the captured evidence.

Inside Denpex

See the evidence, not just the claim

Follow the causal chain, inspect the quoted evidence and prepare the next handoff. These actual product captures use founder-account examples and the VS Code extension, with the source identified under each image. Open a capture to inspect it at full size.

Follow the failure through the cascade

Denpex founder-account example: a causal graph connects an Xid 48 ECC event to a rank exit and downstream collective failures, with quoted evidence for each stage.
Live founder-account capture from the bundled NCCL/ECC example. Follow the hardware event, rank exit and downstream symptoms with a supporting log quote at each stage.Inspect original image

Prepare the hardware escalation

Denpex hardware handoff summary asks the operator to capture diagnostic evidence and verify RMA eligibility with the vendor.
Actual hardware handoff summary from the same founder-account example. Capture diagnostic evidence before an approved reset, then confirm RMA eligibility with the vendor.Inspect original image

Ask for the evidence that is missing

Denpex historical example says a collective timeout does not establish the initiating rank, cause or failure domain and requests distinguishing evidence before a remedy.
Founder-account example restored from history. The original timeout remains unattributed, and the UI keeps the missing-evidence assessment visible.Inspect original image

Keep the investigation in the editor

Denpex VS Code extension displaying a bundled OOM-before-NCCL example, matched log evidence, verification guidance and an investigation handoff.
Actual VS Code extension capture of the bundled OOM-before-NCCL example. Review matched log evidence, verification guidance and the investigation handoff without leaving the editor.Inspect original image