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From "Alexei Fedotov" <alexei.fedo...@gmail.com>
Subject Re: [performance] Startup cost is high for Harmony (HARMONY-6002)
Date Thu, 23 Oct 2008 05:44:24 GMT
Hello Wenlong,
You have addressed a very interesting topic. Let me share few ideas
how to approach it:

1. The first thing I would expect to understand here is why we should
care about "Hello, World" startup. SPEC jvm [0] startup scores are
much more tempting to approach. Then one should compare the score with
one of our competitors. Taking into account that 300 ms = 300 context
switches I would not say that the number itself makes me unhappy about
Harmony speed.

2. Due to some bureaucracy the following tempting [1] idea is still
waiting for an experienced and accurate C coder to complete:
 * load classes into bootstrap class loader once
 * store the internal representation of classes as a memory mapped file;
 * next time, load the file if it exists.

4. If you don't like C, there are tunable things in a class library
you may find using Gregory's JVMTI profiler [2].

[0] http://www.spec.org/jvm2008/
[1] a research shows +10% on "Hello, World"
[2] two first attachments at https://issues.apache.org/jira/browse/HARMONY-4569

On Thu, Oct 23, 2008 at 12:29 AM, Tim Ellison <t.p.ellison@gmail.com> wrote:
> Wenlong Li (JIRA) wrote:
> > The startup time is long for the simple helloworld program. On a Core
> > 2 Quad-core processor, running the simple helloworld program will take
> > more than 300 ms.
> > Can we reduce the startup cost?
> Yes, I hope so ... concrete suggestions or analysis of startup costs are
> welcome.
> Regards,
> Tim

With best regards,

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