db-derby-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Kristian Waagan <Kristian.Waa...@Sun.COM>
Subject Re: Advice in debugging plan selection
Date Wed, 18 Jun 2008 20:20:45 GMT
Kathey Marsden wrote:
> Kathey Marsden wrote:
>>
>> Also I think I might try to gc() before the measurements and see if 
>> that makes a difference, but it seems to me that would only make the 
>> value larger.
>>
> putting runtime.gc() and runtime.runFinalization() before the calls to 
> totalMemory() and freeMemory() seem to stabilize it at 4.
>
> Does that seem like a reasonable solution?  The static block is only 
> called once so it shouldn't impact performance I think.

Can we use the system property "os.arch" to determine this?

I haven't confirmed this, but tried it on a few machines. As far as I 
can see, it returns the "architecture" of the JVM begin run.
So far I have seen these values (all Sun JVMs):
    (machine #1)
    Solaris 10 - x86 32 bit VM: "x86"
    Solaris 10 - x86 64 bit VM: "amd64"
    (machine #2)
    Solaris 10 - sparc 32 bit VM: "sparc"
    Solaris 10 - sparc 64 bit VM: "sparcv9"
    (machine #3)
    Linux x86 32 bit VM: "i386"

If we don't recognize the value we get, we can run the heuristic.
I haven't found any authoritative source/description of the values, but 
we could try to check the source of some of the open-sourced VMs if we 
want to investigate further.

People can also help out by posting the value of "os.arch" seen on their 
computer :)


just a thought,
-- 
Kristian

>
> Kathey
>
>


Mime
View raw message