[mvapich-discuss] How & where to set ulimit ?

[yogeshwar sonawane]

Hi jonathan,
Thanks for the reply.

My comments are inline.

On Thu, Sep 25, 2008 at 10:55 PM, Jonathan Perkins
<perkinjo at cse.ohio-state.edu> wrote:
> On Thu, Sep 25, 2008 at 09:26:00PM +0530, yogeshwar sonawane wrote:
>> Hi all,
>>
>> I am using mvapich2 on OFED stack. Referring to user guide, i have set
>> memlock limit to unlimited in /etc/security/limits.conf &
>> /etc/init.d/sshd. ssh service is restarted. Now, if i do a relogin,
>> ulimit -a should show unlimited. But it is showing 32Kb only. The
>> account used is user account, not root account.
>> Am i doing the correct steps ?
>
> Did you use 'ulimit -l unlimited' in the /etc/init.d/sshd file before it
> created the sshd daemon?  If so, it seems that you're following the
> correct steps.
>
I restart the sshd service

>>
>> I tried to set this command in .bashrc of the user account. But at
>> every login, following error comes:-
>> -bash: ulimit: max locked memory: cannot modify limit: Operation not permitted
>>
>> I tried to set some number, i.e. ulimit -l 4096. This is successful.
>> But setting to 4097 is failing.
>> Can somebody give me the correct steps & info ?
>>
>
> Is there a hard memlock limit set?  You may want to try setting this as
> well to see if this gives you better results.

i have added following line in /etc/security/limit.conf
*               hard    memlock         unlimited
>
> Which Linux distribution are you using?  I found that with RHEL5 I can
> simply set the soft and hard memlock limits in /etc/security/limits.conf
> without even touching /etc/init.d/sshd.
>
my Linux distribution is RHEL 4- update 5-x86_64-Workstation

>> Mainly, i am running HPL. So whether these settings can hamper the
>> performance figures ?
>> OR what are the optimal settings ?
>
> I'm not sure if there is a such thing as optimal settings for this.  It
> depends on how much memory you want to allow user processes to lock
> compared to how much is left for the OS to do its work.
>
>>
>> Thanking you,
>> Yogeshwar
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>
> --
> Jonathan Perkins
> http://www.cse.ohio-state.edu/~perkinjo
>