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david1234

performance issue on a dualcore

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Hi,

I have been using JET for a few years now for our software package and up to know had no major issues (except for memory management in the early days). Now we have a customer with a dualcore 2.79GHz HP machine and following strange behavior:

our old version of the software compiled with JET 5.0 runs at normal speed

our newer version, compiled with JET6.0 runs on this machine several times slower! We are not facing this issue on other PCs which are also dualcore or single core.

I haven't tried 6.0MP1 yet, could this help? Has anyone else seen something like this?

What would you need to help identify the source of the slow down?

Thanks

David

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Hi,

The slowdown is probably caused by using the Classic option of the JET Runtime which is not optimized for HyperThread, multi-core and multi-CPU systems.

Please select the Desktop Runtime on the Target page of JET Control Panel, recompile your application and check its performance.

--ZZ Top

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I checked the compiler settings, and they  were on Deskop runtime.

I also recompiled my application after applying the mainetance pack on 6.0, also with the Desktop runtime: still slow down effect (by this I mean 3 to 5 times slower than a single core with same frequency). This was on a Pentium D 915.

I will run a few tests on various other dual cores I can lay my hand on and also try the beta version of the compiler and will report what I see.

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I also recompiled my application after applying the mainetance pack on 6.0, also with the Desktop runtime: still slow down effect

Run your application on Sun JRE on both single- and multi-core systems and check if the slowdown takes place.

We need to know if the problem is caused by the JET Runtime or the application itself does not scale well.

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Ok will do.

I also did following test:

compiled the application with 6.4beta3 and run on a dual core: it works! So what ever has changed between 6.0/6.0MP1 and 6.4beta3 seems to fix the issue.

I will also run the test with the JRE and report back

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Here are the results running on a JRE 1.6.0_05.

'Action 1' takes 35s on a Pentium M 1.5GHz 1GB RAM

'Action 1' takes 40s on a AMD Athlon 64x dual core4200+ 1GB RAM

=> roughly same time...

JET Compiled:

~ 180 secs on dualcore with 6.0 and 6.0MP1

~  40s on dualcore with 6.4beta3

versus

35/40 sec on Pentium M with 6.0/6.0MP1/6.4b3

Can you please speed up development of 6.4b3  :) which seem to fix this

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~ 180 secs on dualcore with 6.0 and 6.0MP1

Please do the following:

1) write a simple script like this:

----------- run.bat

SET JETVMPROP=-version

SlowApp.exe

--------------------

where "SlowApp.exe" is your application compiled with Excelsior JET 6.0

2) Run SlowApp.exe on the dual-core system to ensure that performance of the executable is poor

3) Once you've confirmed the performance degradation, run the script on the same system and post here what it prints 

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java version "1.6.0_03"

Java 2 Runtime Environment, Standard Edition

Excelsior JET 6.00: RT: Professional edition, build jet-600-release (Fr Dec 07 00:10:58 NOVT 2007)

JET PRofile [1.6.0_03]

Runtime: Desktop [sMP:yes, optimizations: enabled]

Components:

C:\Program Files\PhenoSystems\Gensearch 3.5.1\gensearch3.5.1.exe: jet-600-release (pro, en)

Thanks for your help

David

PS: I will be travelling heavily so my feedback time will slow down, that doesn't indicate that this issue is not important :)

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David,

May we have an example on which the problem can be reproduced?

It's important for us because we have both single and multi-core servers dedicated to performance measurement and none of our tests which include lots of microbenchmarks, standard benchmarks like SPEC, and real applications, shows performance degradation on multi-core systems.

Quite the contrary, the performance figures relative to the standard JRE are better on multi-core boxes.

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OK, I will try to pack something together (datafiles/software), it will take a few days as I am on the road, I hope

to be able to send you something by end of this week

David

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David,

I will try to pack something together (datafiles/software), it will take a few days as I am on the road

It's ok. You may do that at your early convinience.

Please send the necessary files to java at excelsior-usa.com and do not forget to provide instructions on how to reproduce this performance drift.

Thank you for your cooperation.

--ZZ Top

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