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From "Sergey Kuksenko" <sergey.kukse...@gmail.com>
Subject Re: [performance] a few early benchmarks
Date Tue, 28 Nov 2006 15:00:10 GMT
On 11/28/06, Geir Magnusson Jr. <geir@pobox.com> wrote:
>
>
>
> Mikhail Loenko wrote:
> > And we need to make sure that a patch that improves DaCapo by 0.1%
> > does not lower down the SPEC by 10%
>
> Absolutely :)
>
> >
> > We need to agree on a target function to optimize, like some weighted
> mean.
>
> It would be useful to understand what SPECjbb is actually testing - can
> someone describe it?


First of all I wish to cite spec.org:
*--------------------*
*SPECjbb2005 (Java Server Benchmark)* is SPEC's benchmark for evaluating the
performance of server side Java. SPECjbb2005 evaluates the performance of
server side Java by emulating a three-tier client/server system (with
emphasis on the middle tier). The benchmark exercises the implementations of
the JVM (Java Virtual Machine), JIT (Just-In-Time) compiler, garbage
collection, threads and some aspects of the operating system. It also
measures the performance of CPUs, caches, memory hierarchy and the
scalability of shared memory processors (SMPs). SPECjbb2005 provides a new
enhanced workload, implemented in a more object-oriented manner to reflect
how real-world applications are designed and introduces new features such as
XML processing and BigDecimal computations to make the benchmark a more
realistic reflection of today's applications.
SPECjbb2005 Benchmark Highlights

   - Emulates a 3-tier system, the most common type of server-side Java
   application today.
   - Business logic and object manipulation, the work of the middle tier,
   predominate.
   - Clients are replaced by driver threads, database storage by binary
   trees of objects.
   - Increasing amounts of workload are applied, providing a graphical
   view of scalability.

-------------------------------------------<end of citation>

Really, SPECjbb emulates a set of transactions to several warehouses like
"order something, payment, stocks, etc.."

SPECjbb measures performance sequentially on 1,2,3,.... threads that allows
to evaluate scalability.

Also I may comment some details:

- SPECjbb doesn't use any database. It's emulated using java.util API. Such
implementation measures pure Java environment.

- For example - java.math.BigDecimal class is de facto standard
representation for financial calculations. Moreover, JDBC maps DECIMAL (SQL)
data to BigDecimal class. SPECjbb  uses BigDecimal extensively.

- Also SPECjbb uses XML processing for emulation logging like it may be done
in real enterprise system.

Best regards,
---
Sergey Kuksenko.
Intel Enterprise Solutions Software Division.

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