thread dump?

thread dump?

[Mike Perham]

Hi, is there a way to get a thread dump for a Unicorn process? I have a Unicorn which is hanging[0] and I can't tell where it is stuck. Sidekiq uses the TTIN (Thread INfo) signal, Puma uses the INFO signal[1]. Does unicorn have similar?

[0]: https://github.com/sidekiq/sidekiq/issues/5876#issuecomment-1529919584
[1]: https://github.com/puma/puma/pull/1320

Mike

Re: thread dump?

[Mike Perham]

FYI, I got this working with some easy-on-eyes formatting:

after_fork do |server, worker|
    Signal.trap("INFO") do
        Thread.list.each do |th|
            puts("====\n#{th.inspect} #{th.backtrace.join("\n\t")}")
        end
    end
end

On Thu, May 11, 2023, at 07:42, Mike Perham wrote:
> Hi, is there a way to get a thread dump for a Unicorn process? I have a Unicorn which is hanging[0] and I can't tell where it is stuck. Sidekiq uses the TTIN (Thread INfo) signal, Puma uses the INFO signal[1]. Does unicorn have similar?
> 
> [0]: https://github.com/sidekiq/sidekiq/issues/5876#issuecomment-1529919584
> [1]: https://github.com/puma/puma/pull/1320
> 
> Mike

Re: thread dump?

[Eric Wong]

Mike Perham <mike@perham.net> wrote:
> On Thu, May 11, 2023, at 07:42, Mike Perham wrote:
> > Hi, is there a way to get a thread dump for a Unicorn
> > process? I have a Unicorn which is hanging[0] and I can't
> > tell where it is stuck. Sidekiq uses the TTIN (Thread INfo)
> > signal, Puma uses the INFO signal[1]. Does unicorn have
> > similar?

(top-posting corrected)

Not by default.  I've long recommended adding per-callsite timeouts
throughout the app + libraries for portability across various
Rack servers:

  https://yhbt.net/unicorn/Application_Timeouts.html

> > [0]: https://github.com/sidekiq/sidekiq/issues/5876#issuecomment-1529919584
> > [1]: https://github.com/puma/puma/pull/1320
> 
> FYI, I got this working with some easy-on-eyes formatting:
> 
> after_fork do |server, worker|
>     Signal.trap("INFO") do

<snip>

Yes, that works.  Pretty much anything can be setup that way,
and at this point there's probably many configs that would be
broken if unicorn started relying on more signals internally.



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