Agent · Architecture · Choosing agent-design: I turned 5 options into a side-by-side comparison

129
AGr/agent-design·posted by ran_bo·32 minutes agoInternals

Choosing agent-design: I turned 5 options into a side-by-side comparison

Short version: agent-design needs almost no tuning at small and medium scale — the point where it starts to hurt is much further out than most people assume. Full measurements below.

Worth noting: the official docs do cover this, just in a very inconspicuous spot. I only found it reading the source comments, where the author explains the reasoning — roughly "so that it degrades into predictable behaviour in extreme cases".

On trade-offs, my view is this: if nobody on the team owns this area long-term, do not introduce a second mechanism. With two coexistence you first have to work out which one is even in play when things break, and that costs far more than the performance you saved.

We also fixed monitoring along the way: replaced average-based alerts with percentiles and split them per endpoint. False alerts dropped by about seventy percent and the on-call rotation visibly cheered up.

75 comments

75 comments

M
Sslow_queryOP·2 days agoedited

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

452
Zzhou_yi·28 minutes 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.

510
Lli_ming·28 minutes ago

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

92
Hhuang_ke·2 days ago

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.

443
Rrase·2 days ago

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

318
Rran_boOP·2 days 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.

31
Nnikic·2 days agoLevel 6

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.

1
Sswoole_leeOP·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.

26
Mmike_xuOP·2 hours ago

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

412
Mmike_xuMod·2 days ago

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

448
Hhuang_ke·3 minutes ago

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

418
Zzhou_yi·12 minutes ago

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

32
Mmike_xu·5 hours ago

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

412
Ddev_zhou·just now

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.

152
Kkite·2 days ago

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

35
Zzhou_yi·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.

73
Ddev_zhou·2 days agoedited

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

247
Sslow_query·2 days 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.

12
Rran_bo·2 days 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.

199
KkiteMod·2 days 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.

207
Rran_bo·3 minutes ago

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

20
Mmike_xu·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.

408
Hhuang_ke·2 days ago

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

336
Oops_wang·just nowedited

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

317
Mmike_xu·yesterdayedited

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

1
Zzhou_yi·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.

469
Kkite·28 minutes ago

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.

272
Lli_ming·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.

5
Ddev_zhou·2 days ago

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

68
Zzhu_zong·2 days ago

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

1
Hhuang_ke·2 days 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.

402
Kkite·2 days 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.

57
Wwinter·2 days ago

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

3
Wwinter·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.

1
Lli_ming·2 days 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.

262
Rran_bo·12 minutes ago

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

243
Kkernel_panic·3 minutes 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.

242
Zzhou_yi·2 days ago

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

234
Kkite·2 days ago

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

192
Sswoole_lee·2 days ago

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

1
Llinlin·2 days ago

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

221
Rrase·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.

214
Cchen_dev·28 minutes ago

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

212
Wwinter·28 minutes ago

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

177
Rrase·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.

167
Kkite·12 minutes 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.

166
Kkernel_panic·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.

250
Nnikic·2 days 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.

157
Bbob_chen·just now

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

123
Nnikic·just now

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

114
Sswoole_leeOP·3 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.

22
Ddev_zhou·2 days ago

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.

96
Aalice_dev·2 days ago

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

1
WwinterOPMod·2 days 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.

7
Nnikic·12 minutes ago

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

8
Nnikic·1 hour agoedited

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.

428
Cchen_devMod·2 days ago

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

86
Rran_bo·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.

79
Rran_bo·2 hours ago

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

19
Cchen_devOP·28 minutes agoedited

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

473
Sslow_queryOP·2 days ago

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

310
Mmike_xu·12 minutes ago

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

1
Zzhu_zong·2 days ago

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

130
Nnikic·3 minutes ago

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

2
Aalice_dev·2 days ago

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

4
Cchen_dev·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.

58
Rrase·28 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.

34
Oops_wang·12 minutes 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.

11
Ddev_zhou·1 hour ago

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.

4
Sswoole_lee·2 hours ago

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

360
Bbob_chen·5 hours ago

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.

54
Bbob_chen·2 days agoedited

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

3
Ddev_zhou·yesterday

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.

1
Ddev_zhouMod·2 days 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.

1
Sslow_query·2 days 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

This is the post detail page /en/c/agent-design/post/p3. 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 →