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Reducing latency with esoteric Linux process flags

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Re: Reducing latency with esoteric Linux process flags

#4

Post by mannyv »

mmh0000 wrote: post #3

What? The headline does not match the article content at all. There was no reduced latency. The article title should be something along the line of: "Bad architecture resulted in a hard-to-troubleshoot bug"

I suppose the latency was reduced because the process wasn't being terminated by the kernel anymore.

Really, the title should say "PR_SET_PDEATHSIG doesn't mean what you think it means."

The man page for PR_SET_PDEATHSIG: "The parent-death signal is sent upon subsequent termination of the parent thread and also upon termination of each subreaper process"

Re: Reducing latency with esoteric Linux process flags

#5

Post by mannyv »

mannyv wrote: post #4
mmh0000 wrote: post #3

What? The headline does not match the article content at all. There was no reduced latency. The article title should be something along the line of: "Bad architecture resulted in a hard-to-troubleshoot bug"

I suppose the latency was reduced because the process wasn't being terminated by the kernel anymore. Really, the title should say "PR_SET_PDEATHSIG doesn't mean what you think it means." The man page for PR_SET_PDEATHSIG: "The parent-death signal is sent upon subsequent termination of the parent thread and also upon termination of each subreaper process"

I was hoping it was something about reducing process latency by using some obscure IOCTL call or switching the scheduler.

Re: Reducing latency with esoteric Linux process flags

#7

Post by scottlamb »

IshKebab wrote: post #6

Is this exactly the same bug as this very recent post? https://news.ycombinator.com/item?id=43153901

Yes, it is. But clearly in a different codebase. Crazy that two teams were using this same esoteric, broken prctl and diagnosing the problem it caused in such short succession.

Re: Reducing latency with esoteric Linux process flags

#9

Post by sweca »

IshKebab wrote: post #6

Is this exactly the same bug as this very recent post? https://news.ycombinator.com/item?id=43153901

Haha, yea. When I was writing this blog post (we had already pushed to production) I came across that post when searching for sources to confirm my findings. Antonio and I were so surprised at the coincidence.
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