Solaris Sparc Performance Problem

["Douglas E. Hornig" <do...@hornig.net>]

I posed this problem to the good folks on the users list.  While they are a great bunch, and several offered some suggestions, I was unable to get any help from them so I'm trying the dev list now.

The problem in a nutshell is that requests I make to tomcat running on a Solaris Sparc from a Windows client take at least 0.15 to 0.20 seconds.  If I run tomcat on a Linux PC, or use a Linux PC as a client instead of Windows, the turnaround time is more like 0.01 seconds.

Here are the particulars:

* All machines are on the same 100Mbit ethernet.
* Tomcat is running standalone.
* I tried a couple of different Sparcs, a 420R and an Ultra 5, neither with any load.  No difference.
* I wrote a simple Java program to use as the test client so there are no browsers involved.
* I tried various different Java VM releases on the Sparcs, 1.2.1 and 1.3.0 with no difference seen.
* I tried a couple different PCs (NT4 and Win2000) and found the same results.
* Other programmers here reported slowness using VisualBasic as the client instead of Java (that's how I got started investigating this).  Java Web Server 2.0 also appeared to have the same problem as tomcat.  I have not personally been able to verify these assertions.
* The results seem very repeatable.
* I used a generic tomcat 3.2.1 for the server and hit the examples/servlet/HelloWorldExample URL for these tests.

This is a very serious problem for us.  The above mentioned VB client that we're developing can make dozens of calls to the server per screen, so those 0.2 second delays add up.  I like Linux a lot myself but the bosses here feel more comfortable with more traditional business models, and besides shouldn't Java run best on a Sparc with Solaris?  I am perplexed as to what the problem is and would greatly appreciate any help or ideas I can get.

Thanks in advance,

Douglas Hornig
Dartmouth-Hitchcock Medical Center
Lebanon, NH

Re: Solaris Sparc Performance Problem

["Kyle F. Downey" <kd...@amberarcher.com>]

Anne Dirkse wrote:

> Douglas --
> 
> I am experiencing the exact same set of problems, except that I'm just
> beginning to experience them, so I haven't done any real testing to get
> to the specifics of what is going on and the exact performance
> difference that I am experiencing between Solaris and Linux, however,
> there is a noticable slowness even with a single connected client.
>    My setup is:
>     * Solaris 8
>     * All machines also on same 100MB Ethernet
>     * Standalone Tomcat
>     * Using our company's Sparc boxes (500Mhz Sparc) -- only have tried
> these
>     * No performance difference amongst browsers (IE5, Netscape 4.7)
>     * Tried JDK 1.2.2 and 1.3, no difference
>     * Patched Solaris as recommended for Java setup, no difference
> 

By any chance, have you tried hitting the system from another Solaris
box? There is a TCP/IP stack mis-match problem (due to Win32 having a 
less sophisticated implementation) that can cause an idle of up to 0.5
seconds. 

>From http://www.sun.com/sun-on-net/performance/tcp.slowstart.html:

"Only configurations with clients that use a simplistic delayed ACK implementation, 
e.g. Windows/NT, will exhibit the idle time problem when talking to a Solaris server."

They recommend doing the following as root to patch this for Win32 clients:

# ndd -set /dev/tcp tcp_slow_start_initial 2

Give this a shot and let us know if it clears up your problem.

--kd

Re: Solaris Sparc Performance Problem

[Anne Dirkse <al...@uswest.net>]

Douglas --

I am experiencing the exact same set of problems, except that I'm just
beginning to experience them, so I haven't done any real testing to get
to the specifics of what is going on and the exact performance
difference that I am experiencing between Solaris and Linux, however,
there is a noticable slowness even with a single connected client.
   My setup is:
    * Solaris 8
    * All machines also on same 100MB Ethernet
    * Standalone Tomcat
    * Using our company's Sparc boxes (500Mhz Sparc) -- only have tried
these
    * No performance difference amongst browsers (IE5, Netscape 4.7)
    * Tried JDK 1.2.2 and 1.3, no difference
    * Patched Solaris as recommended for Java setup, no difference

The only other problem that I have been encountering which you
apparently have not is that occasionally Tomcat will stop responding
altogehter, and Java will dump core. I have not been able to narrow this
down to a specific cause, but I'm working on that.

I too would rather just head back to Linux, which I'm more comfortable
with anyhow, but since my company sells Sparc/Solaris based server
appliances they seem to like Solaris. :)

Please, if you get any great answers that aren't posted to tomcat-dev
would you share them with me? I'd be glad to do the same.

Good Luck!

"Douglas E. Hornig" wrote:
> 
> I posed this problem to the good folks on the users list.  While they are a great bunch, and several offered some suggestions, I was unable to get any help from them so I'm trying the dev list now.
> 
> The problem in a nutshell is that requests I make to tomcat running on a Solaris Sparc from a Windows client take at least 0.15 to 0.20 seconds.  If I run tomcat on a Linux PC, or use a Linux PC as a client instead of Windows, the turnaround time is more like 0.01 seconds.
> 
> Here are the particulars:
> 
> * All machines are on the same 100Mbit ethernet.
> * Tomcat is running standalone.
> * I tried a couple of different Sparcs, a 420R and an Ultra 5, neither with any load.  No difference.
> * I wrote a simple Java program to use as the test client so there are no browsers involved.
> * I tried various different Java VM releases on the Sparcs, 1.2.1 and 1.3.0 with no difference seen.
> * I tried a couple different PCs (NT4 and Win2000) and found the same results.
> * Other programmers here reported slowness using VisualBasic as the client instead of Java (that's how I got started investigating this).  Java Web Server 2.0 also appeared to have the same problem as tomcat.  I have not personally been able to verify these assertions.
> * The results seem very repeatable.
> * I used a generic tomcat 3.2.1 for the server and hit the examples/servlet/HelloWorldExample URL for these tests.
> 
> This is a very serious problem for us.  The above mentioned VB client that we're developing can make dozens of calls to the server per screen, so those 0.2 second delays add up.  I like Linux a lot myself but the bosses here feel more comfortable with more traditional business models, and besides shouldn't Java run best on a Sparc with Solaris?  I am perplexed as to what the problem is and would greatly appreciate any help or ideas I can get.
> 
> Thanks in advance,
> 
> Douglas Hornig
> Dartmouth-Hitchcock Medical Center
> Lebanon, NH