EPYC 144 core machine has issues with Cygwin PID wraparound

Cedric Blancher cedric.blancher@gmail.com
Fri Dec 20 11:58:05 GMT 2024


On Fri, 20 Dec 2024 at 01:31, Brian Inglis via Cygwin <cygwin@cygwin.com> wrote:
>
> On 2024-12-19 16:42, Corinna Vinschen via Cygwin wrote:
> > On Dec 19 17:20, Cedric Blancher via Cygwin wrote:
> >> Good afternoon!
> >>
> >> We have a new AMD EPYC machine with 144 cores (upgraded from 8 core
> >> machine) running Windows 10 Enterprise, with a mixture of native Win32
> >> apps+Cygwin.
> >> But the Cygwin apps cause trouble, as PID numbers get re-used too
> >> fast. We churn through ~~6912000 child processes EVERY HOUR, which now
> >> causes major problems with PID wraparounds in scripts and perl.
> >>
> >> 1. How can I increase the value at which pid-wraparound will happen?
> >> 2. How can I test for Cygwins max PID value? Cygwin does not have
> >> /proc/sys/kernel/pid_max
> >
> > We can't make the pid algorithm variable in terms of the max pid, so
> > I changed the maximum PID to the maximum pid on Linux, i.e., 4194304.
> >
> > Please check out the next test release cygwin 3.6.0-0.294.g363357c023ce.
>
> Run the attached to check your upgrade:
>
> $ gcc -o cyg_max_pid{,.c} && ./cyg_max_pid
> max pid 65536
>

Can we please get an interface in /proc OR /bin/getconf to get/probe
the maximum pid value?

Ced
-- 
Cedric Blancher <cedric.blancher@gmail.com>
[https://plus.google.com/u/0/+CedricBlancher/]
Institute Pasteur


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