MAX_N_PID should be 4194304 on 64bit machines

[merkys]

While using t-coffee on Debian, it has been noticed that on 64bit machines process IDs (PIDs) exceed the default MAX_N_PID setting (currently 260000) and starts acting weird (please see the original Debian bug report). I would suggest either increasing the default value of MAX_N_PID to 4194304, or doing so only when compiled 64bit machines.

[EricDeveaud]

please do nt set an hard coded value. instead use the value that the OS and kernel may supply

MAX PID can be obtain via 2 calls
eg:
cat /proc/sys/kernel/pid_max
or
sysctl kernel.pid_max

it can also be determined programaticaly

the maxpid value is set by the os and can be edited by admins why 4194304 ? size_t

examples:

maestro-submit:~ > uname -s -p -o -m
Linux x86_64 x86_64 GNU/Linux
maestro-submit:~ > sysctl kernel.pid_max
kernel.pid_max = 65536

tars-submit0:~ > uname -s -p -o -m               
Linux x86_64 x86_64 GNU/Linux
tars-submit0:~ > sysctl kernel.pid_max
kernel.pid_max = 57344

regards

Eric

[cnotred]

Thanks a lot Eric, This is very useful. I will implement this ASAP Cedric Le 1/7/20 à 18:03, Eric Deveaud a écrit :

please do nt set an hard coded value. instead use the value that the OS and kernel may supply MAX PID can be obtain via 2 calls eg: |cat /proc/sys/kernel/pid_max| or |sysctl kernel.pid_max| it can also be determined programaticaly the maxpid value is set by the os and can be edited by admins why 4194304 ? size_t examples: |maestro-submit:~ > uname -s -p -o -m Linux x86_64 x86_64 GNU/Linux maestro-submit:~ > sysctl kernel.pid_max kernel.pid_max = 65536 | |tars-submit0:~ > uname -s -p -o -m Linux x86_64 x86_64 GNU/Linux tars-submit0:~ > sysctl kernel.pid_max kernel.pid_max = 57344 | regards Eric — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#27 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ABML3KLV5AAV3SJZNL72OSDRZNM3RANCNFSM4OBHGCAA>.

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[merkys]

please do nt set an hard coded value. instead use the value that the OS and kernel may supply

Yes, this is a wise solution.

This is very useful. I will implement this ASAP

Do you mean you are going to implement taking the MAX_N_PID from the kernel in tcoffee build system?

[cnotred]

yes, I will implement a procedure that uses the kernel value. Unfortunately, I have just realized there does not seem to be any simple programmatic way to do this on mac OSX, does any body have a suggestion on this? Cedric Le 1/7/20 à 18:15, Andrius Merkys a écrit :

please do nt set an hard coded value. instead use the value that the OS and kernel may supply Yes, this is a wise solution. This is very useful. I will implement this ASAP Do you mean you are going to implement taking the |MAX_N_PID| from the kernel in tcoffee build system? — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#27 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ABML3KIADBYKRNE632C4NSTRZNOIPANCNFSM4OBHGCAA>.

-- ########################################## Dr Cedric Notredame, PhD Group Leader Notredame's lab - Comparative Bioinformatics Group Bioinformatics and Genomics Programme Room 440.03 Centre de Regulació Genòmica (CRG) Dr. Aiguader, 88 08003 Barcelona Spain Ph# + 34 93 316 02 71 Fax# + 34 93 316 00 99 Mobile# + 34 66 250 47 82 email cedric.notredame@crg.eu url www.tcoffee.org blog cedricnotredame.blogspot.com ORC-ID: 0000-0003-1461-0988 ###########################################

[EricDeveaud]

on my mac (Mojave) man 2 setaudit_addr says:

The ai_asid variable contains the audit session ID which is recorded with
     every event caused by the process.  It can be any value in the range 1 to
     PID_MAX (99999).  

http://www.opensource.apple.com/source/xnu/xnu-1699.24.23/bsd/sys/proc_internal.h
#define PID_MAX 99999

Eric

[Hirun]

https://apple.stackexchange.com/questions/51119/whats-the-maximum-pid-for-mac-os-x

Looking at sys/proc_internal.h in xnu-1699.24.23, I find that PID_MAX is 99999. The value is used in kern_fork.c in the function forkproc. Looking at that function, process IDs are not assigned equal to PID_MAX, so the highest possible pid is 99998

Seems like for Mac OS it is ok to hardcode the limit to 99998