Verilog · Beginners · Built a visual debugging panel for verilog-newbie over the weekend

2.4K
VEr/verilog-newbie·posted by zhu_zong·6 hours agoTooling

Built a visual debugging panel for verilog-newbie over the weekend

Some background first. Our setup is verilog-newbie plus three downstream services, seven figures of daily requests, peaking around nine in the evening.

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".

Self-host — full control44%
Managed service — less work28%
Hybrid: core self-hosted17%
Not decided yet11%

4097 votes total

756 comments

756 comments

· first 120 loaded
M
Sslow_query·2 days ago

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

471
Zzhu_zongOP·3 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.

369
Rran_bo·5 hours ago

One counter-example: below verilog-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.

330
Zzhou_yi·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.

52
Ttang_hao·2 days ago

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

23
Sslow_query·2 hours ago

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

370
RraseOP·2 days ago

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

1
Wwinter·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.

366
Wwinter·2 days ago

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

130
Rran_bo·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.

75
Nnikic·28 minutes ago

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

361
Kkernel_panic·1 hour 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.

12
Sswoole_lee·28 minutes ago

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

513
Zzhou_yi·3 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.

57
Hhuang_ke·2 days agoedited

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.

511
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.

387
Mmike_xu·2 days ago

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

169
Kkite·5 hours 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.

66
Zzhu_zong·2 hours 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
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.

172
Lli_ming·2 hours ago

One counter-example: below verilog-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.

1
Sslow_query·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.

43
Aalice_dev·5 hours 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.

11
Rran_bo·2 days agoLevel 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.

236
Cchen_devOP·2 hours agoLevel 6

One counter-example: below verilog-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.

14
Rran_bo·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
Cchen_dev·2 days agoedited

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

294
Sswoole_lee·2 days agoLevel 6

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.

42
Nnikic·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.

17
Sslow_queryOP·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.

17
Hhuang_ke·2 days ago

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

1
Wwinter·28 minutes ago

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

365
Aalice_dev·2 days ago

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

294
Ttang_haoMod·2 days ago

One counter-example: below verilog-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.

199
Kkernel_panic·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
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.

109
Hhuang_keMod·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.

197
Hhuang_ke·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
Cchen_dev·2 days ago

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

333
Rran_bo·just nowedited

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.

327
Aalice_dev·2 days ago

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

475
Lli_ming·2 days ago

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

190
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.

2
Hhuang_ke·yesterdayedited

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.

316
NnikicOP·2 days ago

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

229
Hhuang_ke·2 days ago

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

288
Sslow_queryOP·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.

204
Rran_boOP·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.

17
Ddev_zhou·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.

254
Lli_ming·2 days ago

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

247
Hhuang_ke·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.

217
Kkite·28 minutes ago

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

162
Llinlin·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.

146
Oops_wang·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.

138
NnikicOP·5 hours ago

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

43
Cchen_devOP·2 days ago

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

38
Mmike_xu·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.

252
Oops_wang·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.

182
LlinlinOP·2 days ago

One counter-example: below verilog-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.

39
Sslow_queryOP·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.

34
Sslow_query·2 days ago

One counter-example: below verilog-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.

92
Zzhu_zong·1 hour agoedited

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

86
Zzhu_zongOP·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.

49
Lli_ming·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.

213
Rran_bo·2 days ago

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

143
Cchen_dev·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.

31
Wwinter·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.

77
Aalice_dev·2 days ago

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

81
Kkernel_panic·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.

81
RraseOP·5 hours ago

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

16
Oops_wangMod·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.

72
Kkite·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.

25
Nnikic·2 hours 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.

10
Rran_boOP·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.

8
Aalice_devOP·2 days ago

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

1
Bbob_chen·2 days ago

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

55
Rran_bo·2 days ago

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

517
Sswoole_lee·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.

228
Bbob_chen·2 days agoedited

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.

421
Ttang_haoOP·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.

81
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.

55
Sswoole_lee·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.

17
Llinlin·2 days agoLevel 6

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

182
Oops_wang·yesterdayLevel 6

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

1
Rran_boOP·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.

2
Llinlin·2 days agoedited

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.

54
Ttang_hao·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.

41
Rran_bo·3 minutes agoedited

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

40
Zzhu_zong·3 minutes ago

One counter-example: below verilog-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.

280
Kkernel_panic·just now

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.

67
Lli_ming·2 days ago

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

30
Wwinter·3 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.

28
Aalice_dev·2 days ago

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

158
Zzhou_yi·3 minutes 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.

512
Lli_ming·2 days ago

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

278
Mmike_xu·2 days ago

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

131
Nnikic·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.

116
Hhuang_ke·1 hour ago

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

28
Sswoole_lee·5 hours ago

One counter-example: below verilog-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
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.

27
Cchen_devOP·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.

61
Kkite·2 days ago

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

27
Zzhu_zong·3 minutes ago

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

26
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.

18
Zzhou_yi·2 days ago

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

32
Hhuang_ke·2 days ago

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

247
Rran_boOP·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.

1
Rran_bo·2 hours ago

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

1
Zzhou_yi·2 days ago

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

14
Llinlin·28 minutes ago

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

12
Rrase·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.

11
Wwinter·2 days ago

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

11
Ttang_hao·3 minutes ago

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

9
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.

6
Oops_wang·just now

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

6
Mmike_xu·3 minutes ago

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

6
Aalice_dev·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.

2
Bbob_chen·3 minutes ago

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

135
Aalice_dev·2 days ago

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

318
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.

220

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