[Opensim-dev] Memory cache
Melanie
melanie at t-data.com
Thu May 21 18:55:44 UTC 2009
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
>>> > > >
>>> > > >
>>> > > >
>>> > > > ---------------------------------------------------------------------
>>> > > ---
>>> > > >
>>> > > > _______________________________________________
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