TensorRT · Beginners · Open-sourced a rate-limiting middleware for tensorrt-newbie with token bucket and sliding window

1.8K
TEr/tensorrt-newbie·posted by winter·1 hour agoOpen source

Open-sourced a rate-limiting middleware for tensorrt-newbie with token bucket and sliding window

It took me two weeks of on-and-off digging and plenty of wrong turns. Writing the process down as it happened so the next person spends less time.

Order of investigation, by return on effort: 1. Check downstream latency first — usually it is not your problem 2. Then pool hit rate and wait-queue length 3. Only then GC and allocation 4. Suspect the framework last

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.

The first thing was to collapse the variables. We were changing config and upgrading the version at the same time, and afterwards nobody could say which change caused what. We rolled back to moving one variable at a time, re-ran three times, and only then did the curve settle. Tedious, but not skippable.

1004 comments

1004 comments

· first 120 loaded
M
Sslow_query·2 days ago

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

508
Aalice_devOP·2 days ago

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

438
Aalice_dev·1 hour 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.

495
Hhuang_keOP·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.

339
Cchen_dev·2 days ago

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

23
Hhuang_keOP·yesterday

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

253
Zzhou_yiMod·1 hour 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.

240
Oops_wang·2 days ago

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

3
Ttang_hao·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.

39
Cchen_dev·just nowLevel 6

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.

193
Rran_bo·2 days agoLevel 6

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.

8
Kkernel_panic·2 hours 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.

2
Sswoole_lee·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.

71
WwinterOP·2 days agoedited

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

343
Nnikic·3 minutes 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
Cchen_dev·28 minutes agoedited

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

464
Ddev_zhou·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.

280
Rrase·12 minutes ago

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

503
Ttang_hao·2 days ago

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

21
Rran_bo·2 days ago

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

291
Sswoole_lee·2 hours agoedited

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

257
Wwinter·just now

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.

222
Kkernel_panic·2 days ago

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

200
Nnikic·2 days ago

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

187
RraseOP·2 days agoedited

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

112
Sslow_query·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.

161
Oops_wangMod·28 minutes 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.

156
Wwinter·1 hour ago

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

310
Cchen_devOP·2 days ago

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

204
Kkernel_panic·2 hours ago

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

6
Wwinter·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.

236
NnikicOP·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.

65
Hhuang_ke·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.

64
Wwinter·2 days agoLevel 6

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.

76
Oops_wangMod·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.

31
Rrase·2 days ago

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

149
Kkite·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.

148
Rrase·2 days ago

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

85
Ddev_zhou·2 hours ago

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

66
Cchen_dev·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.

148
Kkite·2 hours ago

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

134
RraseOP·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.

73
Rran_bo·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.

122
Zzhou_yi·2 days ago

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

214
Hhuang_ke·2 days ago

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

94
Rran_bo·2 days agoedited

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

79
Zzhou_yi·just now

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

502
Cchen_dev·2 days agoedited

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.

430
Bbob_chen·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.

342
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.

215
Bbob_chenMod·2 days ago

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

1
Zzhu_zong·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.

2
Aalice_dev·2 days agoedited

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

79
Zzhou_yiMod·12 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.

73
Ttang_hao·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.

1
Sslow_query·2 days ago

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

63
Aalice_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.

62
Lli_mingOP·2 days agoedited

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

1
Ttang_haoOP·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
Zzhou_yi·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.

44
Lli_ming·28 minutes ago

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

38
Rran_boMod·2 days agoedited

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.

196
Aalice_dev·2 hours 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.

147
Rrase·2 days ago

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

350
Rran_bo·12 minutes agoedited

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

203
Bbob_chen·just now

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.

11
Cchen_dev·2 days agoedited

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.

36
Kkernel_panic·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.

131
Hhuang_ke·2 days ago

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

414
Lli_ming·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.

23
Mmike_xu·yesterday

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

392
Aalice_dev·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.

379
Sslow_query·2 days agoedited

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

127
Rrase·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.

39
Nnikic·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.

383
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.

198
Ddev_zhou·yesterdayeditedLevel 6

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

377
Kkernel_panic·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.

193
Lli_ming·just now

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

4
Cchen_dev·2 days ago

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

38
Rrase·3 minutes ago

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

30
Nnikic·28 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.

228
Sswoole_leeOP·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.

8
Cchen_devOP·2 days ago

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

214
Zzhou_yi·1 hour ago

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

97
Aalice_dev·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.

3
NnikicOP·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.

6
Rran_bo·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.

378
Kkite·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.

156
Mmike_xu·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.

25
Kkernel_panic·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.

47
Ttang_hao·2 days agoedited

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

5
Ttang_hao·28 minutes 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.

2
Bbob_chen·2 days agoLevel 6

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.

11
Aalice_dev·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.

26
Hhuang_keMod·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.

24
Llinlin·28 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.

24
Zzhu_zong·2 days ago

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

24
Cchen_devOPMod·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.

228
Rran_bo·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.

45
Cchen_dev·2 days ago

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

78
Mmike_xu·just now

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

20
Oops_wang·just now

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

12
Bbob_chen·2 days ago

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

12
Kkernel_panic·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.

8
Sswoole_lee·2 days ago

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

275
Ttang_hao·2 days agoedited

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

6
Wwinter·5 hours 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.

87
Llinlin·just now

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.

4
Nnikic·just now

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.

45
Sswoole_lee·2 days ago

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

63
Sswoole_lee·2 days ago

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

54
Kkite·2 days ago

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

5
Sswoole_lee·2 days ago

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

204
Oops_wangMod·2 days ago

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

24
Kkite·3 minutes ago

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

57
Aalice_devOP·2 days ago

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

343
Ttang_hao·2 days ago

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

4
Hhuang_ke·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.

1
Sslow_query·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.

1

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