[Opensim-dev] Memory cache

Nebadon Izumi nebadon2025 at gmail.com
Thu May 21 18:57:38 UTC 2009 

osgrid has seen 0% increase in traffic to the asset server.

http://assets.osgrid.org/stats

have a look for yourself.


On Thu, May 21, 2009 at 11:55 AM, Melanie <melanie at t-data.com> wrote:

> Indeed, it might be it's not really working....
>
> Melanie
>
>
> Mic Bowman wrote:
> > is there any instrumentation in the asset cache about hit rate? the
> > fact that there is no measurable increase reported on the osgrid asset
> > server with the caches turned off suggests that the cache isn't really
> > absorbing many hits (either because its not working the way its
> > expected to or because the re-use isn't significant).
> >
> > --mic
> >
> >
> > On Thu, May 21, 2009 at 11:43 AM,  <diva at metaverseink.com> wrote:
> >> The cache, as configured, has 32K asset slots, which is a lot. So it
> >> takes a while until the cache releases some objects for the GC to
> >> collect. I think there's something else going on with that cache --
> >> probably too many locking conflicts between threads, or something like
> >> that. Whatever it is, it's much heavier than fetching the assets from
> >> the remote asset server, which is amazing. And another amazing thing is
> >> that remote fetching of so many assets at the same time (whenever a
> >> client connects) has such good observable performance for the user.
> >>
> >> If the purpose of the cache is to go easy on the asset server (not
> >> necessarily improve the observable performance, which is already very
> >> good without the mem cache) it might make more sense to use a file
> >> system / local DB instead of a memory cache.
> >>
> >> Stefan Andersson wrote:
> >>> If the cache is releasing objects, I think we might well be seeing
> >>> LOH fragmentation.
> >>>
> >>> http://msdn.microsoft.com/en-us/magazine/cc534993.aspx
> >>>
> >>> The solution would then be to break the binaries apart into byte cucks
> >>> smaller than the LOH trshold.
> >>>
> >>> Best regards,
> >>> Stefan Andersson
> >>>
> >>>
> >>>
> >>>
> >>>  > From: adam at deepthink.com.au
> >>>  > To: opensim-dev at lists.berlios.de
> >>>  > Date: Wed, 20 May 2009 17:21:51 -0400
> >>>  > Subject: Re: [Opensim-dev] Memory cache
> >>>  >
> >>>  > We are using an external caching library I believe, it could be
> >>> sitting in there.
> >>>  >
> >>>  > Adam
> >>>  >
> >>>  > > -----Original Message-----
> >>>  > > From: opensim-dev-bounces at lists.berlios.de [mailto:opensim-dev-
> >>>  > > bounces at lists.berlios.de] On Behalf Of Melanie
> >>>  > > Sent: Wednesday, 20 May 2009 1:56 PM
> >>>  > > To: opensim-dev at lists.berlios.de
> >>>  > > Subject: Re: [Opensim-dev] Memory cache
> >>>  > >
> >>>  > > The surprise really is that the cache would be a performance loss
> >>>  > > instead of a performance gain. What is there that makes it so
> slow?
> >>>  > >
> >>>  > > Melanie
> >>>  > >
> >>>  > > Frisby, Adam wrote:
> >>>  > > > As chief engineer aboard the USS OSgrid, I might want to
> recommend
> >>>  > > against this.
> >>>  > > >
> >>>  > > > Not having the sims cache assets will mean that every asset
> request
> >>>  > > will hit the core asset server which in turn will result in higher
> >>>  > > bandwidth requirements for it in the long run. It doesn't appear
> to
> >>>  > > have made a huge impact on our bandwidth charts for this week yet
> -
> >>>  > > however I wouldn't be surprised if it did if everyone did this.
> >>>  > > >
> >>>  > > > Adam
> >>>  > > >
> >>>  > > > From: opensim-dev-bounces at lists.berlios.de [mailto:opensim-dev-
> >>>  > > bounces at lists.berlios.de] On Behalf Of Nebadon Izumi
> >>>  > > > Sent: Wednesday, 20 May 2009 10:19 AM
> >>>  > > > To: diva at metaverseink.com; opensim-dev at lists.berlios.de
> >>>  > > > Subject: Re: [Opensim-dev] Memory cache
> >>>  > > >
> >>>  > > > Yay for mistakes that end in gains!!! of course if anyone asks i
> >>>  > > planned this ;P anyway i thought people would like to see my ini
> >>>  > > changes.. this is what lead to the discovery:
> >>>  > > >
> >>>  > > > [OpenSim.ini]
> >>>  > > > ; The following is the configuration section for the new style
> >>>  > > grid servers
> >>>  > > > ; If you don't know what this is, don't enable it. It will eat
> >>>  > > your data,
> >>>  > > > ; format your hard drive and make all meat in your fridge spoil.
> >>>  > > > ; You have been warned.
> >>>  > > > ; Some of this is starting to work!
> >>>  > > > [Modules]
> >>>  > > > ; Choose one
> >>>  > > > ;AssetServices = "LocalAssetServicesConnector"
> >>>  > > > AssetServices = "RemoteAssetServicesConnector"
> >>>  > > > ;AssetServices = "HGAssetBroker"
> >>>  > > >
> >>>  > > > ; If you don't want asset caching in the regions, comment this
> >>>  > > > AssetCaching = "CoreAssetCache" ;<<<---*** SEE ERROR HERE ***---
> >>>  > > ->>>
> >>>  > > >
> >>>  > > > ; Choose one
> >>>  > > > ;UserServices = "LocalUserServicesConnector"
> >>>  > > > UserServices = "RemoteUserServicesConnector"
> >>>  > > >
> >>>  > > >
> >>>  > > > [AssetService]
> >>>  > > > ; Parameters for local assets, formerly known as "standalone"
> >>>  > > > LocalServiceModule =
> >>>  > > "OpenSim.Services.AssetService.dll:AssetService"
> >>>  > > > StorageProvider = "OpenSim.Data.SQLite.dll"
> >>>  > > > ;StorageProvider = "OpenSim.Data.MySQL.dll"
> >>>  > > > ;ConnectionString = "Data Source=localhost;Database=opensim;User
> >>>  > > ID=opensim;Password=opensim;"
> >>>  > > > DefaultAssetLoader =
> >>>  > > "OpenSim.Framework.AssetLoader.Filesystem.dll"
> >>>  > > > AssetLoaderArgs = "assets/AssetSets.xml"
> >>>  > > >
> >>>  > > > ; Parameters for remote assets, formerly known as "grid"
> >>>  > > > AssetServerURI = "http://assets.osgrid.org:8003/"
> >>>  > > >
> >>>  > > > ; Paremeters for the Hypergrid connector
> >>>  > > >
> >>>  > > > ;; Parameters for the HG Broker
> >>>  > > > ; Use this one if you have a standalone grid
> >>>  > > > ;LocalGridAssetService =
> >>>  > > "OpenSim.Services.AssetService.dll:AssetService"
> >>>  > > > ; Use this one if this sim is connected to a grid-wide asset
> >>>  > > server
> >>>  > > > ;LocalGridAssetService =
> >>>  > > "OpenSim.Services.Connectors.dll:AssetServiceConnector"
> >>>  > > > ;HypergridAssetService =
> >>>  > > "OpenSim.Services.AssetService.dll:HGAssetService"
> >>>  > > >
> >>>  > > > [AssetCache]
> >>>  > > > ; Number of buckets for assets
> >>>  > > > CacheBuckets = 32768
> >>>  > > >
> >>>  > > > [UserService]
> >>>  > > > ;LocalServiceModule =
> >>>  > > "OpenSim.Services.UserService.dll:UserService"
> >>>  > > >
> >>>  > > > [/OpenSim.ini]
> >>>  > > >
> >>>  > > > Please test this out and see if you see gains too and let us
> know.
> >>>  > > >
> >>>  > > > Neb
> >>>  > > >
> >>>  > > >
> >>>  > > >
> >>>  > > >
> ---------------------------------------------------------------------
> >>>  > > ---
> >>>  > > >
> >>>  > > > _______________________________________________
> >>>  > > > Opensim-dev mailing list
> >>>  > > > Opensim-dev at lists.berlios.de
> >>>  > > > https://lists.berlios.de/mailman/listinfo/opensim-dev
> >>>  > > _______________________________________________
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> >>>  > > Opensim-dev at lists.berlios.de
> >>>  > > https://lists.berlios.de/mailman/listinfo/opensim-dev
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> >>>
> >>>
> >>>
> ------------------------------------------------------------------------
> >>>
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-- 
Michael Emory Cerquoni - Nebadon Izumi @ http://osgrid.org
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