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From: Kevin McMurtrie on 2 Jun 2010 00:42
In article <alpine.DEB.1.10.1006011632420.16785(a)urchin.earth.li>,
Tom Anderson <twic(a)urchin.earth.li> wrote:

> Hello,
>
> A colleague mentioned that he'd heard (from this guy's cousin's mechanic's
> guy who he met in a bar's grandfather's dealer's sysop) that the JVM
> requests memory from the OS in chunks of the size of -Xms, and that you
> should therefore always set -Xmx to be a whole multiple of -Xms, otherwise
> it would never actually request its way up to it (because you can't make a
> litre from any whole number of fluid ounces).
>
> I think i'd heard something similar at some point, although from a less
> reliable source.
>
> Is there any truth to this? Was there ever?
>
> tom

Nope.

I don't know if it holds true for 1.6, but heap growth had performance
problems in 1.4 and 1.5 so setting ms and mx to the same value helped
some applications. Searching bug reports are a great way to gather
information about edge cases like this.
--
I won't see Google Groups replies because I must filter them as spam
From: Mike Schilling on 2 Jun 2010 00:59


"Kevin McMurtrie" <mcmurtrie(a)pixelmemory.us> wrote in message
news:4c05e127$0$22132$742ec2ed(a)news.sonic.net...

>
> I don't know if it holds true for 1.6, but heap growth had performance
> problems in 1.4 and 1.5 so setting ms and mx to the same value helped
> some applications. Searching bug reports are a great way to gather
> information about edge cases like this.


It's still true that if you know the app will grown to at least N during its
life, you might as well set ms to N. Otherwise you're just causing
unnecessarily expensive GCs while it grows.

From: Daniel Pitts on 2 Jun 2010 13:07
On 6/1/2010 9:59 PM, Mike Schilling wrote:
>
>
> "Kevin McMurtrie" <mcmurtrie(a)pixelmemory.us> wrote in message
> news:4c05e127$0$22132$742ec2ed(a)news.sonic.net...
>
>>
>> I don't know if it holds true for 1.6, but heap growth had performance
>> problems in 1.4 and 1.5 so setting ms and mx to the same value helped
>> some applications. Searching bug reports are a great way to gather
>> information about edge cases like this.
>
>
> It's still true that if you know the app will grown to at least N during
> its life, you might as well set ms to N. Otherwise you're just causing
> unnecessarily expensive GCs while it grows.
Set which? MX or MS?

--
Daniel Pitts' Tech Blog: <http://virtualinfinity.net/wordpress/>
From: Lew on 2 Jun 2010 18:44
Mike Schilling wrote:
>> ... you might as well set ms to N.

Daniel Pitts wrote:
> Set which? MX or MS?

--
Lew
From: Daniel Pitts on 2 Jun 2010 19:09
On 6/2/2010 3:44 PM, Lew wrote:
> Mike Schilling wrote:
>>> ... you might as well set ms to N.
>
> Daniel Pitts wrote:
>> Set which? MX or MS?
>
Ah, my mind must have filtered "ms" into "it" for some reason.

Anyway, I disagree about that. I would think that ms should be set to
the "average case", and mx to the "worst case that we want to succeed"


--
Daniel Pitts' Tech Blog: <http://virtualinfinity.net/wordpress/>
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