LILinux Community
Community homeHot discussions Latest posts Best of Knowledge base Resources About

Linux Community · Discussion: is the linux ecosystem being replaced by another stack?

140
LIr/linux·posted by huang_ke·1 hour agoJobs

Discussion: is the linux ecosystem being replaced by another stack?

Most linux articles stop at "how to use it" and never cover "when not to use it". This is an attempt at the second half.

One last trap: in container environments remember to adjust the memory-related parameters in step. Otherwise the host limit and the process expectation disagree, and the symptom is intermittent, unreproducible failure.

Image placeholder · object storage in production
POST /api/uploads → CDN origin pull
22 comments

22 comments

M
NnikicOP·yesterday

There is actually a simpler fix that needs no architecture change: move this check up to the gateway and the problem disappears. The cost is one extra lookup at the gateway.

512
Bbob_chen·yesterday

Sharing our numbers, 8 cores 16GB, same scenario:

| Concurrency | P50 | P99 |
|---|---|---|
| 200 | 12ms | 88ms |
| 500 | 31ms | 340ms |

P99 clearly collapses at 500 concurrency, which lines up with your knee point.

427
Hhuang_ke·just now

I just read the linux source — the author actually explains the reasoning in a comment, roughly "so that it degrades into predictable behaviour in extreme cases".

364
Zzhu_zong·2 days ago

Can you give a minimal reproduction? I ran it locally for ten minutes and could not reproduce on macOS with the latest version.

158
Bbob_chen·2 days ago

We have run this in production for two years without hitting it. That said, we never reached this scale, so our experience is not really evidence here.

84
Bbob_chenOP·1 hour ago

We have run this in production for two years without hitting it. That said, we never reached this scale, so our experience is not really evidence here.

7
Ttang_hao·just now

A question: what changes in a container with a 512Mi memory limit? That is how we run it in production.

308
Hhuang_ke·just now

I see point 3 differently. The trade-off depends on your read/write ratio: read-heavy with little writing means caching actually widens the inconsistency window.

250
Ttang_hao·12 minutes ago

Agreeing with the above. One addition: with this option enabled the GC count in your metrics doubles, so adjust the alert threshold at the same time or it will keep firing.

239
Kkite·12 minutes ago

This matches what we see in production. We only hit it past 3k QPS; the earlier load tests showed nothing — the test traffic was too clean, with no long-tail requests.

230
Wwinter·yesterday

One counter-example: below linux 7.4 the semantics of that code are different, so do not copy it verbatim. We got burned in staging and rolled back once.

357
Hhuang_keMod·12 minutes ago

Worth learning from this debugging approach. We went straight at the logs and took a much longer route.

301
Aalice_dev·2 days agoedited

Has anyone run a controlled experiment? I did, reducing it to a single variable, and the difference was 4% — within noise. So I suspect the main cause is something else.

86
Nnikic·1 hour ago

Saved. I am reworking this area this week — this saves a lot of wrong turns.

1
Aalice_devMod·2 days ago

This is not a linux problem, it is a usage problem. The docs say this API is not thread-safe and you must lock around it yourself.

510
Rran_bo·28 minutes ago

Worth learning from this debugging approach. We went straight at the logs and took a much longer route.

5
Zzhou_yi·12 minutes ago

I see point 3 differently. The trade-off depends on your read/write ratio: read-heavy with little writing means caching actually widens the inconsistency window.

1
Ddev_zhou·2 days ago

Saved. I am reworking this area this week — this saves a lot of wrong turns.

407
Cchen_dev·1 hour ago

Sharing our numbers, 8 cores 16GB, same scenario:

| Concurrency | P50 | P99 |
|---|---|---|
| 200 | 12ms | 88ms |
| 500 | 31ms | 340ms |

P99 clearly collapses at 500 concurrency, which lines up with your knee point.

39
Zzhu_zong·3 minutes ago

This is not a linux problem, it is a usage problem. The docs say this API is not thread-safe and you must lock around it yourself.

1
Lli_ming·2 days ago

Has anyone run a controlled experiment? I did, reducing it to a single variable, and the difference was 4% — within noise. So I suspect the main cause is something else.

369
Sswoole_lee·3 minutes ago

Thanks for sharing real numbers — far more useful than the articles that only cover concepts.

16

This is the post detail page /en/c/linux/post/p2. Posts and comments are generated deterministically from a seeded PRNG, so the same post always renders the same content and the link can be shared, reloaded and indexed. In production this page reads MySQL for the post, Redis for hot-post caching, and fetches the whole comment tree in a single query on the path column.

See the database schema →