max_thread_proc.5 (2010 09)

m
max_thread_proc(5) max_thread_proc(5)
(Tunable Kernel Parameters)
NAME
max_thread_proc - defines the maximum number of concurrent threads allowed per process.
VALUES
Failsafe
256
Default
256
Allowed values
Between 64 and nkthread
Recommended values
256
DESCRIPTION
max_thread_proc
is a dynamic tunable that limits the maximum number of threads allowed per pro-
cess on the system. When tuning
max_thread_proc
, the maximum number of threads allowed per
process will be the new value of
max_thread_proc. No process will be able to create new threads such
that the total count of its threads exceeds
max_thread_proc
.
Who is Expected to Change This Tunable?
System administrators that run applications on their systems requiring a high number of threads per pro-
cess.
Restrictions on Changing
The effect of tuning
max_thread_proc
on existing processes is undefined. However, existing threads
will not be effected.
When Should the Value of This Tunable Be Raised?
The value of
max_thread_proc
should be raised if there is a need to run an application that requires a
higher number of threads per process than what
max_thread_proc
is currently set to accommodate.
Also, if thread creation fails with the
errno value of EAGAIN, then it could indicate that the
max_thread_proc has been reached. However, reaching
max_thread_proc is not the only reason
why a thread creation could fail with
EAGAIN. EAGAIN may be returned if the nkthread system tun-
able has been reached or memory on the system is exhausted.
What Are the Side Effects of Raising the Value?
A group of processes may be able to exhaust the system wide limit of threads on the system.
When Should the Value of This Tunable Be Lowered?
If you feel that it is necessary to limit the number of threads allowed per process.
What Are the Side Effects of Lowering the Value?
Some applications which need a high number of threads may behave differently or fail to operate.
What Other Tunable Values Should Be Changed at the Same Time?
You may want to look at the value of
nkthread.
WARNINGS
All HP-UX kernel tunable parameters are release specific. This parameter may be removed or have its
meaning changed in future releases of HP-UX.
Installation of optional kernel software, from HP or other vendors, may cause changes to tunable parame-
ter values. After installation, some tunable parameters may no longer be at the default or recommended
values. For information about the effects of installation on tunable values, consult the documentation for
the kernel software being installed. For information about optional kernel software that was factory
installed on your system, see HP-UX Release Notes at http://www.hp.com/go/hpux-core-docs.
AUTHOR
max_thread_proc was developed by HP.
HP-UX 11i Version 3: September 2010 − 1 − Hewlett-Packard Company 1