Same image, 3x performance difference between deployments — is this host placement?
theoakagency
HOBBYOP

4 hours ago

Hi,

I'm on the Hobby plan running a Python image-processing service, and I'm seeing large performance variance between deployments that I'd like to understand before deciding whether to upgrade.

The pattern: a given container is either fast or slow for its entire lifetime, and it flips at the next redeploy. Same image digest, same code, no config changes. Across roughly 25 containers over five days, about four were consistently ~3x slower than the rest on identical workloads. A slow container stays slow until it's replaced, and the replacement is usually fast again with no intervention.

The part that makes me think it's host-level rather than resource limits: during slow periods the service uses fewer total CPU-seconds than during fast ones, while wall-clock time triples. The work appears to lose parallelism — operations that normally spread across several cores seem to run on about one. The container never approaches its own CPU or memory limits in either case (peaks around 1.3 vCPU against 8 available, and about 500MB of RAM).

My questions:

  1. Does host placement or CPU allocation differ between Hobby and Pro? I'm trying to work out whether Pro would reduce this variance, or whether it only raises limits I'm not currently hitting.

  2. Is there anything about how CPU is allocated on shared infrastructure that would explain a workload losing effective parallelism on some hosts but not others?

  3. Is dedicated compute available below the Enterprise tier, or is that the only option for consistent performance?

Thanks,

John

$10 Bounty

1 Replies

Railway
BOT

4 hours ago

This thread has been opened as a bounty so the community can help solve it.

Status changed to Open Railway about 4 hours ago


manuproject
HOBBYTop 5% Contributor

4 hours ago

im also on hobby, this looks like cpu contention on a shared host, not your limits, since you're nowhere near your ceiling.

  1. hobby shares cpu with other tenants via cgroup quotas, pro might get better priority but not sure it removes contention fully, staff would know .

  2. yes, contention causes exactly this, your threads wait their turn on a busy host so work loses parallelism, thats why cpu-seconds drops while wall clock triples

  3. not sure on dedicated compute below enterprise, worth asking staff directly


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