For high-performance computing and distributed training leads

Pinpoint which straggler rank or RoCE link slowed down your Crusoe Cloud cluster.

Compare per-rank step completion drift, shared storage checkpoint durations, and RDMA pause frames before a slow worker trips the global NCCL watchdog.

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Live diagnosis, no signup

Replay a resolved Crusoe Cloud Slurm straggler 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

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Upload or drop a plain-text log

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

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

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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.

What a useful evaluation should establish

Establish whether a timeout was caused by a straggler compute node, storage write barrier, or network pause frame congestion.

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.

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

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

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

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

Failure Signature Triage

Crusoe Cloud - Observed Runtime Evidence

Read Crusoe documentation

Incident pattern summary

A 16-node Slurm job on Crusoe Cloud times out during model checkpointing at step 5,000. Rank 0 through 119 wait at a broadcast barrier while Rank 120 stalls writing shard state to a congested mount point, causing the 10-minute NCCL watchdog to abort the entire run.

Terminal traceback excerpt (Crusoe Cloud)

slurmstepd: error: *** STEP 48192.0 ON crusoe-h100-015 CANCELLED AT 2026-10-21T09:14:22 ***
[E ProcessGroupNCCL.cpp:915] [Rank 0] Watchdog caught collective operation timeout: WorkNCCL(SeqNum=5001, OpType=BROADCAST, Timeout(ms)=600000)
[Rank 120] Checkpoint save to /mnt/shared/checkpoints/step_5000_shard_15.pt took 642.4s (expected < 30.0s)

Recommended verification flags

Set these environment flags in your training container or launch script to capture high-resolution collective logs:

NCCL_DEBUG=INFOTORCH_NCCL_ENABLE_MONITORING=1TORCH_NCCL_HEARTBEAT_TIMEOUT_SEC=600

Diagnostic Scope Boundary

Denpex cannot tune Crusoe Cloud storage throughput tiers or modify Slurm scheduler partitions. The evaluation isolates whether the stall originated in collective networking, GPU compute throttling, or storage I/O.