Re: [WDSCI-L] WAS / WebFacing performance?? -- MIDRANGE-L

Mike,
 
As promised a update....
We think to have gotten to a maximal reasonable setting.
This means that overall performance for Webfacing Users is acceptable as long 
we do not things extra (not logging to much, no admin console running during 
office hours, and so on).
Since this is a fragile equilibrium we have advised our client to add more RAM 
to his configuration.
They will add 2 Gb of RAM and we will evaluate the results when things are 
running with it.
 
With all the investigations that have being done we have not found a way to 
keep track on the GC information automatically.
Within WAS Admin Console you can select to collect this information but in the 
monitor it self the info does not appear.
This info seems not to be available when on JDK 1.4
 
Anyone knows of alternatives....
 
Kind regards,
Eduard.


----- Original Message ----
From: "eduard@xxxxxxxxxxxxxxxxxxxxxxx" <eduard@xxxxxxxxxxxxxxxxxxxxxxx>
To: Websphere Development Studio Client for iSeries <wdsci-l@xxxxxxxxxxxx>
Sent: Thursday, March 1, 2007 10:22:41 AM
Subject: Re: [WDSCI-L] WAS / WebFacing performance??


Mike,

We have done some tuning to trigger GC more often by adjusting the Initial 
HeapSize of the WAS instance running the Application.
The default was 96Mb and brought it back to 40Mb on this 1CPU 1GB ram 520 
machine.
This has brought back the time used for GC from 80 to 500 seconds to 2 to 30 
seconds.
This has also improved the performance perception of the users using the 
webfaced application considerably.
The GC times gathered we have done with DMPJVM because we could not find an 
appropiate way to do this in an automated way.
To know how would really help because we then can plot the time and moments 
used for GC with the results on the PMI performance we have found we can do 
within the WAS server. 
We have activated this PMI functionality to get a view of the actual action 
performance (do action, what time did it cost to complete action).
As we understand now we can only get this information on a running base.
That is nice, but much nicer is as we can get this over a time. We than could 
see the effect of the changes applied and can easier figure out what is the 
most ideal value in the given setting.

I must assume these possibilities exist, just have not stumbled on.
I have people working on this, if anyone knows how or where to look, please let 
me know.

Keep you all informed.

Eduard.

----- Original Message ----
From: Mike Hockings <hockings@xxxxxxxxxx>
To: Websphere Development Studio Client for iSeries <wdsci-l@xxxxxxxxxxxx>
Sent: Friday, February 16, 2007 2:25:51 PM
Subject: Re: [WDSCI-L] WAS / WebFacing performance??


Hi Eduard, I can appreciate how you feel ;-)

  I am sure the performance can be improved, from what I understand of it 
you really want the GC to run more often but with less to do each time. In 
any case here are a couple of things that I have found which could help 
your quest...

I (and others too, I am sure) would be most interested to hear how it 
turns out.

Mike

WebSphere tuning for the impatient: How to get 80% of the performance 
improvement with 20% of the effort
http://www-128.ibm.com/developerworks/websphere/library/techarticles/0602_lurie/0602_lurie.html

Tuning garbage collection for Java and WebSphere running classic JVM on 
i5/OS 
http://www-03.ibm.com/servers/enable/site/education/wp/c566/index.html

Mike Hockings, P.Eng.
WebSphere Development Tools for AS/400  -  CODE/Designer & WebFacing !
IBM Canada Ltd. Laboratory 
hockings@xxxxxxxxxx 
voice 905 413 3199




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Re: [WDSCI-L] WAS / Webfacing performance??






Mike,

When it happens all the users are slow.
We also see excessive non DB paging in the *BASE pool (over the thousandth 
for as well the Faults as the Pages) whilst no considerable CPU is used. 
We have tried the stop and refresh the browser, that does not seem to have 
a effect.

I guess the above boils down to the GC assumption.
I'm trying to learn about how to control that (I do understand the 
concepts for GC but poor native iSeries bastards like me never had to 
worry about these kind of things, but 'progress' has reached us) but could 
not get straight answers.
Hope some knows more than I do and can help.

Kind regards,
Eduard,


----- Original Message ----
From: Mike Hockings <hockings@xxxxxxxxxx>
To: Websphere Development Studio Client for iSeries <wdsci-l@xxxxxxxxxxxx>
Sent: Thursday, February 15, 2007 12:02:09 PM
Subject: Re: [WDSCI-L] WAS / Webfacing performance??


Does the slowdown happen for only the single user or for all users ?   If 
it is for all users then I would suspect something like the GC but if it 
is for a single user then I would suspect browser settings or 
communications somehow.   When you see it something you might try is 
hitting stop then refresh on the browser and see if that makes it pick up 
the pace a bit.  I have also heard, indirectly, that some of this type of 
performance problems can be related to routers in the intranet needing to 
be rebooted or needing a firmware update.  But I will quickly add that I 
myself don't know how to make that sort of determination.

It would seem to me that if the performance is ok before and after the 
"slowness" that the memory you have should be sufficient. 

Mike

Mike Hockings, P.Eng.
WebSphere Development Tools for AS/400  -  CODE/Designer & WebFacing !
IBM Canada Ltd. Laboratory 
hockings@xxxxxxxxxx 
voice 905 413 3199




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Re: [WDSCI-L] WAS / Webfacing performance??






Thanks Mike and others... 

Lets start with asuming it is an garbage collection problem.....
How can we inflict GarbageCollection more often (so it has less to do).

We had already looked at other aspects like network traffic and Browser 
problems (Just because we did not want to start with pointing at the 
iSeries or WAS or Webfacing).
We could not find reasons in these for what is experienced.

Yes, we also where positively surprised with the performance of 
WAS/Webfacing on a rather slim box.

If it turns out that we need more RAM, what would be an reasonable total 
of RAM to add?
We want to be pretty sure upfront that it will bring back the problem to 
an acceptable level (5 minutes reponse time brought back to 2.5 minutes is 

a lot but is still not acceptable).

Kind regards,
Eduard,

----- Original Message ----
From: Mike Hockings <hockings@xxxxxxxxxx>
To: Websphere Development Studio Client for iSeries <wdsci-l@xxxxxxxxxxxx>
Sent: Wednesday, February 14, 2007 1:25:28 PM
Subject: Re: [WDSCI-L] WAS / Webfacing performance??


Hi Eduard,

I can think of a couple of things that might cause those symptoms, maybe. 

First of all I wonder if the starting of a session or the displaying of a 
new (busy) page may be causing the JVM to initiate garbage collection?  I 
don't know if that would cause a slowdown or not but it might.  Possibly 
getting the GC to run more often (so it has less to do) may alleviate it 
if this turns out to be the problem?

The other thing that I could think of is that it seems sometimes IE 
doesn't seem to like to play well with WAS.  I have never been able to 
definitely track this down but by setting the IE cache settings to 
"Automatic" it seems to provide the best results.  If you have to "check 
every page" you can get occasional dismal or worse response times.

Mike

Mike Hockings, P.Eng.
WebSphere Development Tools for AS/400  -  CODE/Designer & WebFacing !
IBM Canada Ltd. Laboratory 
hockings@xxxxxxxxxx 




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Subject
[WDSCI-L] WAS / Webfacing performance??






Dear all,

We have Webfaced Applications running under WAS 6.0 running on a 520 
Express (1GB RAM).
On average the performance is very good (comparable with Green Screen).
Sometimes however the performance drops and it takes minutes to get a 
response.
That happens most often when initiating a session.
Less common it happens while executing the main (larger) programs (with 
lots of fields on the screen).
There seems no relation with the total of users using the system at that 
moment.
Stopping the session and initiating a new one most often give a normal 
response time. 

When it happens we do not see a lot of CPU usage.
We do see a lot of Non DB paging.

What could be the reason/cause for this?
What can be done to get rid if it/get it under control?

Kind regards,
Eduard.