[mapguide-internals] Raster provider problems...

[Traian Stanev]

Yes I agree about rasters being IO bound for the most part. On the other hand, single threading things hurts me deep inside.
 
Traian
 

	-----Original Message----- 
	From: mapguide-internals-bounces at lists.osgeo.org on behalf of Frank Warmerdam (External) 
	Sent: Sat 4/7/2007 2:05 PM 
	To: MapGuide Internals Mail List 
	Cc: 
	Subject: Re: [mapguide-internals] Raster provider problems...
	
	

	Traian Stanev wrote:
	> Yes I understand all that.
	>
	> But mostly working is way better than none at all. That's all I was trying
	> to say.
	>
	> That, or every request for a raster -- even for formats that would work fine
	> -- will have to pass through the same critical section in order to
	> synchronize access. I wouldn't call that an enterprise class solution
	> either.
	
	Traian,
	
	Frankly I don't see this as a major impediment.  Raster access is generally
	io limited, so having two threads accessing rasters off the same physical
	disk is likely to result in seek-thrashing as much as it is likely to help
	performance.
	
	So, in my not-so-humble-opinion, single threading the fdogdal provider is
	not going to appreciably reduce throughput - assuming that other non-fdogdal
	activity in mapguide can continue for other requests.
	
	In some circumstances - for instance with raster data spread over multiple
	physical disks, or for compressed formats where there is a lot of processor
	overhead to decompress, multi-threading might help significantly on a multi
	processor system.
	
	Best regards,
	--
	---------------------------------------+--------------------------------------
	I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
	light and sound - activate the windows | http://pobox.com/~warmerdam
	and watch the world go round - Rush    | President OSGeo, http://osgeo.org <http://osgeo.org/> 
	
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