Re: Location of Tomcat 7 jvm defualt ysettings...

["Genibre, Nicolas (Citco)" <NG...@citco.com>]

U

----- Original Message -----
From: Mark Thomas [mailto:markt@apache.org]
Sent: Friday, July 20, 2012 10:53 PM
To: Tomcat Users List <us...@tomcat.apache.org>
Subject: Re: Location of Tomcat 7 jvm defualt settings...

On 20/07/2012 21:42, Tony Anecito wrote:
> Thanks Charles I have found documention for all the below from the
> Tomcat group but seemed somewhat outdated. Mark Thomas's name seemed
> dominant in most of the presentations I have seen there is even
> sections dealing with Tomcat in various Tomcat books I have seen.
> 
> True the tuning is dependent somewhat upon the app but even Mark
> mentioned logging levels, threads that run contineously that might
> best be tuned off (like checking for new deploys ect). He also
> mentioned the xmx xms java tuning and what Tomcat without apps (WARs)
> loaded needs although not sure if he mentioned xss parimeters. I am
> using the G1 GC by default since that is setup in 1.7.0_05 and the
> compressed pointers is also setup by default for that version of
> 1.7.0_05. I am also looking at the OS level to remove uneeded
> services. I alreadt tuned the network transport parameters as best as
> possible.
> 
> FYI I currently am down to the 1-2msec response times as measured at
> the exposed web services methods inside of Tomcat 7 using 64-bit
> Oracle 1.7.0_05 JDK and that includes database calls to SQL Server
> 2012 Express. I have used some of the standard things mentioned by
> Mark Thomas which has helped alot and looking for more current tips.

I'm pretty sure that I will have said somewhere in each of those
presentations words to the effect of "Don't guess where the bottlenecks
are. Get yourself a profiler, profile your application and find out
where they really are."

If the profiler highlights any Tomcat internal code, let us know and
we'll take a look.

I'll also add something that I picked up at JavaOne a few years ago.
Pick any two of "high throughput, small heap, low GC pause times".
Whichever two you pick, the other one will suffer. In an ideal world,
the GC needs plenty of manoeuvring room and you should aim to provide
roughly 5 times the minimum memory your app needs (minimum being defined
as the lowest heap usage you can force with lots of manual GC).

HTH,

Mark

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