[Glass] GC on Gems only fired when temp space is over?

[Mariano Martinez Peck via Glass]

On Mon, Jun 22, 2015 at 2:16 PM, Dale Henrichs via Glass <
glass at lists.gemtalksystems.com> wrote:

>
>
> On 06/19/2015 02:28 PM, Mariano Martinez Peck via Glass wrote:
>
>> Hi guys,
>>
>> I wanted to know if the following assumption is correct... Imagine I have
>> a stone/gems that I do not use frequently. There is 1 stone and 4 seaside
>> gems. I do understand that when local temp memory of a gem is running out
>> of space, a scavenge is done so that young objects can die, then move
>> survivors, maybe flash out to disk persistent objects not referenced
>> anymore etc etc.  Now.. imagine that I have a .. .700MB temp object space.
>> And since I have 4 gems, I may randomly use a different one for each
>> request (I have no session affinity). So imagine that now my temp space for
>> my gems are all around 500MB. The memory is not yet filled and there is yet
>> some more space.
>>
>> The question is...imagine I do not use this stone/gems for some time...a
>> couple of days. The question is...are these 500MB of memory retained by the
>> gems until I use it again and I run out of space? Isn't the scavenge run
>> every some time besides the "run on running out of memory that would
>> trigger a scavenge"?
>>
> scavenges and mark sweep are only triggered under memory pressure, so it
> is possible for idle gems to consume "too much memory"


OK, that's what I imagined.


>
>
>> What things could I do here to improve this scenario?
>>
>> 1) make temp space smaller..but that would impact when I DO use it
>>
> It is a good question as to why you need such a large TOC ... if your
> working set occasionally balloons to require that much space then you need
> that much space ...


Well... this is a finance app...so most of the times, when they are using
it, I normally need a high TOC.. By default I am using 60/70 % of SPC.
But...there might not be many concurrent users at some point, so yes, I
would like to minimize memory consumed by idle gems.


>
>  2) maybe use session affinity so that at least I fill up less gems? (if
>> there are little concurrent sessions)
>>
>>
> You could schedule a periodic scavenge and mark sweep in your seaside vms
> ...


How can I do this if above you said *"scavenges and mark sweep are only
triggered under memory pressure"  ?*


> Once an hour or so would make sure that your idle seaside gems are using
> the bare minimum of memory ... it may tak a mark sweep for the vm to return
> memory pages ... BTW, I assume that you are running on linux. On the mac
> the full memory footprint is allocated in memory ...
>
>
I would love to do that. Any idea how?
I also saw a thread of Otto today with a (maybe?) related topic. Do you
think what he does could help me too?

Thanks in advance!




> Dale
>
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-- 
Mariano
http://marianopeck.wordpress.com
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