Sam Saffron <[email protected]> wrote:
> Hi Eric / everyone :)
>
> I would like to start graphing how long our master process spends
> waiting for worker processes to be available.
Fwiw, the master doesn't wait for workers to become available for
processing requests. But I think I know what you mean to ask :>
Rather, the connection request sits in the listen queue (a kernel
object) shared by all workers, and instrumenting this is always
kernel-dependent (because unicorn avoids doing stuff in userspace).
> This metric will allow us to quickly tell if a unicorn is being
> overloaded and allow us to quickly remediate.
>
> Once a minute I want to ask the master process how long it spent
> waiting for child processes to become available.
>
> How would I go about getting that metric?
Linux-only, but you can probably look at Raindrops::LastDataRecv
https://bogomips.org/raindrops/Raindrops/LastDataRecv.html
Raindrops::Middleware can give you how big the listen queue is,
too. Ideally, this should never exceed 1.
https://bogomips.org/raindrops/Raindrops/Middleware.html
You can probably get the same metrics directly from the kernel
via systemtap, dtrace, or similar, too.
--
unsubscribe: [email protected]
archive: https://bogomips.org/unicorn-public/
