kernal value - max_thread_proc question.

[Gino Castoldi_2]

Hi,

Svr: HP-UX 11.0 Oracle MC/SG 11.09 OVO NNM

Our servers (two nodes running OVO) have this
kernel parameter max_thread_proc=64.
We need to update that value to 1024.

Are there any issues with doing this?
Are there any related kernel parameters that we need to update as well?

10 points to any good answer.
TIA, Gino

[Dave Olker · Accepted solution]

Hi Gino,

I cover this parameter in detail in my NFS performance technical paper and my "Optimizing NFS Performance" book.

If you adjust this parameter you should also be careful to adjust the "nkthread" parameter and the "ncallout" parameter. If you increase the maximum number of threads for each process to start (max_thread_proc) then your overall number of threads will likely increase, thus nkthread needs to be increased. If you increase the number of threads on the system, you will need to increase the callout table accordingly by tuning ncallout.

Again, there are more details in my technical paper and book. The technical  paper is located at:

http://www.docs.hp.com/hpux/onlinedocs/1435/NFSPerformanceTuninginHP-UX11.0and11iSystems.pdf

and one of the last sections discusses kernel parameter tuning.

Hope this helps,

Dave

[Sundar_7]

max_thread_proc indicates the maximum number of threads a process can create

nkthread stands for the maximum number of threads that can be running in the system.

nkthread by default is based on the value of NPROC.(NPROC*7)/4)+16).

As long as your NPROC is at a reasonable limit and as long as you are not going to be running way too many threaded applications in the system, tuning max_thread_proc should not require changes to the nkthread.

[Hemanth Gurunath Basrur]

Hi Gino,

Did you check the manpage of max_thread_proc on HP-UX 11.00 system?

Also, refer the foll. links for reference:

http://docs.hp.com/cgi-bin/fsearch/framedisplay?top=/hpux/onlinedocs/TKP-90202/TKP-90202_top.html&con=/hpux/onlinedocs/TKP-90202/00/00/93-con.html&toc=/hpux/onlinedocs/TKP-90202/00/00/93-toc.html&searchterms=max_thread_proc&queryid=20040907-124341

http://docs.hp.com/cgi-bin/otsearch/getfile?id=/hpux/onlinedocs/939/KCParms/KCparam.MaxThreadsPerProcess.html&searchterms=max_thread_proc&queryid=20040907-124341

HTH.

Regards,
Hemanth

[rick jones]

If each of those threads will have some file descriptors open, you may also need to look at maxfiles/maxfiles_lim and perhaps even nfile.