userlibandfileserver/fileserver/sfile/sf_file_cache_defs.h
author Dremov Kirill (Nokia-D-MSW/Tampere) <kirill.dremov@nokia.com>
Mon, 18 Jan 2010 21:31:10 +0200
changeset 36 538db54a451d
parent 0 a41df078684a
child 80 597aaf25e343
permissions -rw-r--r--
Revision: 201003 Kit: 201003
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// Copyright (c) 2006-2009 Nokia Corporation and/or its subsidiary(-ies).
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// All rights reserved.
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// This component and the accompanying materials are made available
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// under the terms of the License "Eclipse Public License v1.0"
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// which accompanies this distribution, and is available
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// at the URL "http://www.eclipse.org/legal/epl-v10.html".
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//
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// Initial Contributors:
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// Nokia Corporation - initial contribution.
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//
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// Contributors:
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//
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// Description:
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// f32\sfile\sf_file_cache_defs.h
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// This file contains default settings for file caching. 
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// Some of these settings may be overriden by appropriate entries in the estart.txt file
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// Sizes / lengths specified in kilobytes, timeouts in miliseconds
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// 
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//
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/**
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 @file
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 @internalTechnology
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*/
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// Global file-cache settings 
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const TBool KDefaultGlobalCacheEnabled			= ETrue; 
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const TInt KDefaultGlobalCacheSize				= (32*1024);	// 32768 K = 32 MBytes - the maximum for all files
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// The maximum amount of locked data allowed for all files
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const TInt KDefaultGlobalCacheMaxLockedSize	= (1*1024);		// 1 Mb maximum locked data
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// Low memory threshold as a percentage of total RAM.
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// If the amount of RAM drops below this value, attempts to allocate memory for a file caching will fail
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const TInt KDefaultLowMemoryThreshold			= 10;			// 10 % of total RAM
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// per-drive file-cache settings. 
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const TInt KDefaultFileCacheMaxReadAheadLen	= (128);	// 128K	// NB non-configurable by estart
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const TInt KDefaultFileCacheSize				= (256);	// 256K
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const TInt KDefaultFairSchedulingLen			= (128);	// 128K
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enum {EFileCacheFlagOff, EFileCacheFlagEnabled, EFileCacheFlagOn};
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// default drive cache settings - these may be overridden by estart.txt settings or file open mode 
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const TInt KDefaultFileCacheRead				= EFileCacheFlagEnabled;
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const TInt KDefaultFileCacheReadAhead			= EFileCacheFlagOn;		// NB only enabled if read caching also enabled
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const TInt KDefaultFileCacheWrite				= EFileCacheFlagEnabled;
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/**
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If set to ETrue, media driver reads on this drive are considered to be asynchronous 
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i.e. interrupt driven. This results in read-aheads being issued before completing a client read request.
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If set to EFalse, media driver reads on this drive are considered to be synchronous 
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i.e. issuing a read-ahead is likely to block any client thread which will normally be running at
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lower priority than the media driver's thread. In this case read-aheads only happen during periods 
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of inactivity so as to improve latency: this is achieved by lowering the process of the drive thread
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if there is only one read-ahead request in the drive thread's queue.
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*/
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const TInt KDefaultFileCacheReadAsync			= ETrue;
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// time after which a file will be removed from closed file queue
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const TInt KDefaultClosedFileKeepAliveTime = 3000;			// 3,000 ms = 3 seconds
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// time after which a file containing dirty data will be flushed
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const TInt KDefaultDirtyDataFlushTime = 3000;				// 3,000 ms = 3 seconds
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