Re: [Condor-users] PASSWD_CACHE_REFRESH in 6.9.4?

["Ian Chesal" <ICHESAL@xxxxxxxxxx>]

> If you want to increase the priority of the schedd, that is 
> possibly a 
> good idea.  However, using SHADOW_RENICE_INCREMENT=10 to decrease the 
> priority of the shadows below all other normal processes on 
> the system 
> degrades throughput in every case we have observed or tested 
> in the 6.9 
> branch.  Part of the problem is that the schedd and the 
> shadow need to 
> communicate.  During this communication, it is actually 
> possible for the 
> schedd to be slowed down because it is stuck waiting for a 
> response from 
> a low priority shadow.  More common is to see connection 
> failures in the 
> shadow logs due to the shadow being so cpu starved that it 
> cannot form a 
> connection to the schedd, even with very generous timeouts.

Very interesting. I'm really keen to try 6.9 now. It almost sounds like
we should try starting out with a vanilla configuration set for 6.9 and
retuning things from scratch. So much has appeared to changed with the
release.
 
> Another thing that has changed is that the 6.9.4 schedd is 
> much less cpu 
> hungry than 6.8.  Having 10s of thousands of jobs in the 
> queue and a few 
> thousand jobs running should not severely tax the 6.9.4 schedd on 
> reasonable server-class hardware unless the jobs are so fast that the 
> completion rate is greater than ~10-15 jobs per second.

This is fantastic news.
 
> I'll admit that our tests of this have all been under linux and have 
> been focussed on vanilla universe.  We're certainly hoping 
> for feedback 
> on all the other possible usage cases.

I'll be no help here. That's exactly the setup we're using.

- Ian


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