Re: Master + slave + job JVM memory tuning...

[Johno Crawford]

As James mentioned it really depends on how many jobs you have and what 
you are actually building, project size etc. Off the top of my head here 
are some tips:


If you do not require more than 2GB on Windows or 3GB on Linux I 
recommend using a 32-bit JVM (64-bit JVM uses double the space for every 
pointer), if 32-bit JVM is not an option you may be interested in 
investigating the CompressedOops JVM switch [1].


Enable the com.sun.management.jmxremote JVM switch and connect to your 
JVMs with VisualVM [2]. Doing so will allow you to monitor how much heap 
and perm gen your JVM is occupying, from this it should be straight 
forward to tune the values.


Cheers,

Johno

[1] https://wikis.oracle.com/display/HotSpotInternals/CompressedOops
[2] http://visualvm.java.net/


On 7/01/2013 7:36 PM, Jeff wrote:


Thanks...I unfortunately can't be in the UK for the event.

So if the amount of RAM is fixed (4GB), what is a good rule of thumb 
for determining what to allocate to the slave process, how many 
executors it can reasonably support, etc?


I realize there are a lot of other variables but any starting point 
and things to consider or factor in that may not be obvious could help.


Or is it just a matter or monitoring and tuning?

On Jan 7, 2013 2:31 AM, "Nord, James" <mailto:jn...@nds.com>> wrote:


Have enough RAM on the slave that you can run your jobs plus
Jenkins + some for overhead.

(e.g. 1GB of Jenkins slave, + #executors * ( 2GB for Maven +2GB
for unit tests in forked VM) + OS overhead)

 Although this amount is mostly an overkill setting it too close
to the threshold will slow your jobs down due to paging at best,
or mean you get intermittent failures due to OOM at worst –
(memory is generally cheaper that human time taken to investigate
issues!)  (our maven jobs can be very memory hungry so your
figures will vary)  (Note I recommend a single executor per slave)

The master depends more on how many jobs / reports per jobs / job
history you have etc – we use 10GB (but not tomcat).

If you’re in the UK and there is any spaces left I will cover some
things like this next week at the Jenkins User Event.

/James

*From:*jenkinsci-users@googlegroups.com
<mailto:jenkinsci-users@googlegroups.com>
[mailto:jenkinsci-users@googlegroups.com
<mailto:jenkinsci-users@googlegroups.com>] *On Behalf Of *Jeff
*Sent:* 04 January 2013 21:56
*To:* jenkinsci-users@googlegroups.com
<mailto:jenkinsci-users@googlegroups.com>
*Subject:* Master + slave + job JVM memory tuning...

I'm trying to optimize how much memory I allocate to the master
application (aka - tomcat), slave processes, maven tasks, etc. and
going crazy.

I've been unsuccessful in finding a guideline to determine how
much memory I ought to allocate or if I should just let the
defaults work.

All machines are single processor, dual core with 4 GB ram.

I've typically set tomcat to use 2048MB + 512MB permgen space and
set my maven process to use 384MB max.  Is this reasonable?

My slaves are set to run 4 executors.  Jobs use either svn or git
to check out code and Maven to build with a SONAR post-build
analysis.  We also do Maven releases at times.

How much does the core slave process need?  Is there a
"rule-of-thumb" based on the number of executors?

Any perspective/considerations/resources/links/pointers are much
appreciated.


-- 


Jeff Vincent
predato...@gmail.com <mailto:predato...@gmail.com>
See my LinkedIn profile at:
http://www.linkedin.com/in/rjeffreyvincent

I ♥ DropBox <http://db.tt/9O6LfBX> !!






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:: Johnathan Crawford
:: Senior Software Developer

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Re: Master + slave + job JVM memory tuning...

[teilo]

I would never advise more than one executor per slave :-o

 At some point there will be unit test failures in a project as it has 
badly written unit tests that blindly assume they can use port 12345 (and 
it will be in use for a different job - and then fight each other).  And it 
will be the CI systems fault and come at a time that the most awkward for 
you (the project is trying to release, and you are about to leave for the 
weekend!)
The exception to this would be where the jenkins job is acting more as a 
controller and the work is being performed on some other system.

/James

On Monday, 7 January 2013 18:36:58 UTC, Jeff Vincent wrote:
>
> Thanks...I unfortunately can't be in the UK for the event.  
>
> So if the amount of RAM is fixed (4GB), what is a good rule of thumb for 
> determining what to allocate to the slave process, how many executors it 
> can reasonably support, etc?  
>
> I realize there are a lot of other variables but any starting point and 
> things to consider or factor in that may not be obvious could help.
>
> Or is it just a matter or monitoring and tuning?
> On Jan 7, 2013 2:31 AM, "Nord, James" > wrote:
>
>>  Have enough RAM on the slave that you can run your jobs plus Jenkins + 
>> some for overhead.
>>
>> (e.g. 1GB of Jenkins slave, + #executors * ( 2GB for Maven +2GB for unit 
>> tests in forked VM) + OS overhead) 
>>
>>  Although this amount is mostly an overkill setting it too close to the 
>> threshold will slow your jobs down due to paging at best, or mean you get 
>> intermittent failures due to OOM at worst – (memory is generally cheaper 
>> that human time taken to investigate issues!)  (our maven jobs can be very 
>> memory hungry so your figures will vary)  (Note I recommend a single 
>> executor per slave)
>>
>>  
>>
>> The master depends more on how many jobs / reports per jobs / job history 
>> you have etc – we use 10GB (but not tomcat).
>>
>>  
>>
>> If you’re in the UK and there is any spaces left I will cover some things 
>> like this next week at the Jenkins User Event.
>>
>>  
>>
>> /James
>>
>>  
>>
>> *From:* jenkins...@googlegroups.com  [mailto:
>> jenkins...@googlegroups.com ] *On Behalf Of *Jeff
>> *Sent:* 04 January 2013 21:56
>> *To:* jenkins...@googlegroups.com 
>> *Subject:* Master + slave + job JVM memory tuning...
>>
>>  
>>  
>> I'm trying to optimize how much memory I allocate to the master 
>> application (aka - tomcat), slave processes, maven tasks, etc. and going 
>> crazy.
>>  
>>  
>>  
>> I've been unsuccessful in finding a guideline to determine how much 
>> memory I ought to allocate or if I should just let the defaults work.
>>  
>>  
>>  
>> All machines are single processor, dual core with 4 GB ram.  
>>  
>>  
>>  
>> I've typically set tomcat to use 2048MB + 512MB permgen space and set my 
>> maven process to use 384MB max.  Is this reasonable?
>>  
>>  
>>  
>> My slaves are set to run 4 executors.  Jobs use either svn or git to 
>> check out code and Maven to build with a SONAR post-build analysis.  We 
>> also do Maven releases at times.
>>  
>>  
>>  
>> How much does the core slave process need?  Is there a "rule-of-thumb" 
>> based on the number of executors?
>>  
>>  
>>  
>> Any perspective/considerations/resources/links/pointers are much 
>> appreciated.
>>  
>>
>> -- 
>>  
>> Jeff Vincent
>> preda...@gmail.com 
>> See my LinkedIn profile at:
>> http://www.linkedin.com/in/rjeffreyvincent
>>  
>> I ♥ DropBox <http://db.tt/9O6LfBX> !!  
>>   
>> --
>>
>>
>>
>> **
>> This message is confidential and intended only for the addressee. If you 
>> have received this message in error, please immediately notify the 
>> postm...@nds.com  and delete it from your system as well as 
>> any copies. The content of e-mails as well as traffic data may be monitored 
>> by NDS for employment and security purposes. To protect the environment 
>> please do not print this e-mail unless necessary.
>>
>> NDS Limited. Registered Office: One London Road, Staines, Middlesex, TW18 
>> 4EX, United Kingdom. A company registered in England and Wales. Registered 
>> no. 3080780. VAT no. GB 603 8808 40-00
>>
>> **
>>  
>

RE: Master + slave + job JVM memory tuning...

[Jeff]

Thanks...I unfortunately can't be in the UK for the event.

So if the amount of RAM is fixed (4GB), what is a good rule of thumb for
determining what to allocate to the slave process, how many executors it
can reasonably support, etc?

I realize there are a lot of other variables but any starting point and
things to consider or factor in that may not be obvious could help.

Or is it just a matter or monitoring and tuning?
On Jan 7, 2013 2:31 AM, "Nord, James"  wrote:

>  Have enough RAM on the slave that you can run your jobs plus Jenkins +
> some for overhead.
>
> (e.g. 1GB of Jenkins slave, + #executors * ( 2GB for Maven +2GB for unit
> tests in forked VM) + OS overhead)
>
>  Although this amount is mostly an overkill setting it too close to the
> threshold will slow your jobs down due to paging at best, or mean you get
> intermittent failures due to OOM at worst – (memory is generally cheaper
> that human time taken to investigate issues!)  (our maven jobs can be very
> memory hungry so your figures will vary)  (Note I recommend a single
> executor per slave)
>
>
>
> The master depends more on how many jobs / reports per jobs / job history
> you have etc – we use 10GB (but not tomcat).
>
>
>
> If you’re in the UK and there is any spaces left I will cover some things
> like this next week at the Jenkins User Event.
>
>
>
> /James
>
>
>
> *From:* jenkinsci-users@googlegroups.com [mailto:
> jenkinsci-users@googlegroups.com] *On Behalf Of *Jeff
> *Sent:* 04 January 2013 21:56
> *To:* jenkinsci-users@googlegroups.com
> *Subject:* Master + slave + job JVM memory tuning...
>
>
>
> I'm trying to optimize how much memory I allocate to the master
> application (aka - tomcat), slave processes, maven tasks, etc. and going
> crazy.
>
>
>
> I've been unsuccessful in finding a guideline to determine how much memory
> I ought to allocate or if I should just let the defaults work.
>
>
>
> All machines are single processor, dual core with 4 GB ram.
>
>
>
> I've typically set tomcat to use 2048MB + 512MB permgen space and set my
> maven process to use 384MB max.  Is this reasonable?
>
>
>
> My slaves are set to run 4 executors.  Jobs use either svn or git to check
> out code and Maven to build with a SONAR post-build analysis.  We also do
> Maven releases at times.
>
>
>
> How much does the core slave process need?  Is there a "rule-of-thumb"
> based on the number of executors?
>
>
>
> Any perspective/considerations/resources/links/pointers are much
> appreciated.
>
>
> --
>
> Jeff Vincent
> predato...@gmail.com
> See my LinkedIn profile at:
> http://www.linkedin.com/in/rjeffreyvincent
>
> I ♥ DropBox <http://db.tt/9O6LfBX> !!
>
> --
>
>
>
> **
> This message is confidential and intended only for the addressee. If you
> have received this message in error, please immediately notify the
> postmas...@nds.com and delete it from your system as well as any copies.
> The content of e-mails as well as traffic data may be monitored by NDS for
> employment and security purposes. To protect the environment please do not
> print this e-mail unless necessary.
>
> NDS Limited. Registered Office: One London Road, Staines, Middlesex, TW18
> 4EX, United Kingdom. A company registered in England and Wales. Registered
> no. 3080780. VAT no. GB 603 8808 40-00
>
> **
>

RE: Master + slave + job JVM memory tuning...

[Nord, James]

Have enough RAM on the slave that you can run your jobs plus Jenkins + some for 
overhead.
(e.g. 1GB of Jenkins slave, + #executors * ( 2GB for Maven +2GB for unit tests 
in forked VM) + OS overhead)
 Although this amount is mostly an overkill setting it too close to the 
threshold will slow your jobs down due to paging at best, or mean you get 
intermittent failures due to OOM at worst – (memory is generally cheaper that 
human time taken to investigate issues!)  (our maven jobs can be very memory 
hungry so your figures will vary)  (Note I recommend a single executor per 
slave)

The master depends more on how many jobs / reports per jobs / job history you 
have etc – we use 10GB (but not tomcat).

If you’re in the UK and there is any spaces left I will cover some things like 
this next week at the Jenkins User Event.

/James

From: jenkinsci-users@googlegroups.com 
[mailto:jenkinsci-users@googlegroups.com] On Behalf Of Jeff
Sent: 04 January 2013 21:56
To: jenkinsci-users@googlegroups.com
Subject: Master + slave + job JVM memory tuning...

I'm trying to optimize how much memory I allocate to the master application 
(aka - tomcat), slave processes, maven tasks, etc. and going crazy.

I've been unsuccessful in finding a guideline to determine how much memory I 
ought to allocate or if I should just let the defaults work.

All machines are single processor, dual core with 4 GB ram.

I've typically set tomcat to use 2048MB + 512MB permgen space and set my maven 
process to use 384MB max.  Is this reasonable?

My slaves are set to run 4 executors.  Jobs use either svn or git to check out 
code and Maven to build with a SONAR post-build analysis.  We also do Maven 
releases at times.

How much does the core slave process need?  Is there a "rule-of-thumb" based on 
the number of executors?

Any perspective/considerations/resources/links/pointers are much appreciated.

--
Jeff Vincent
predato...@gmail.com<mailto:predato...@gmail.com>
See my LinkedIn profile at:
http://www.linkedin.com/in/rjeffreyvincent
I ♥ DropBox<http://db.tt/9O6LfBX> !!




**
This message is confidential and intended only for the addressee. If you have 
received this message in error, please immediately notify the 
postmas...@nds.com and delete it from your system as well as any copies. The 
content of e-mails as well as traffic data may be monitored by NDS for 
employment and security purposes. To protect the environment please do not 
print this e-mail unless necessary.

NDS Limited. Registered Office: One London Road, Staines, Middlesex, TW18 4EX, 
United Kingdom. A company registered in England and Wales. Registered no. 
3080780. VAT no. GB 603 8808 40-00
**

Master + slave + job JVM memory tuning...

[Jeff]

I'm trying to optimize how much memory I allocate to the master application
(aka - tomcat), slave processes, maven tasks, etc. and going crazy.

I've been unsuccessful in finding a guideline to determine how much memory
I ought to allocate or if I should just let the defaults work.

All machines are single processor, dual core with 4 GB ram.

I've typically set tomcat to use 2048MB + 512MB permgen space and set my
maven process to use 384MB max.  Is this reasonable?

My slaves are set to run 4 executors.  Jobs use either svn or git to check
out code and Maven to build with a SONAR post-build analysis.  We also do
Maven releases at times.

How much does the core slave process need?  Is there a "rule-of-thumb"
based on the number of executors?

Any perspective/considerations/resources/links/pointers are much
appreciated.

-- 
Jeff Vincent
predato...@gmail.com
See my LinkedIn profile at:
http://www.linkedin.com/in/rjeffreyvincent
I ♥ DropBox  !!