annotate base/StorageAdviser.cpp @ 335:02d2ad95ea52 spectrogram-cache-rejig

* Get storage advice for each cache in an FFT data server.  Allows us to be
  more confident about the actual memory situation and cut over from memory
  to disc part way through an FFT calculation if necessary.  StorageAdviser
  is now a bit too optimistic though (it's too keen to allocate large numbers
  of small blocks in memory).

/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */

/*
    Sonic Visualiser
    An audio file viewer and annotation editor.
    Centre for Digital Music, Queen Mary, University of London.
    This file copyright 2006 QMUL.
    
    This program is free software; you can redistribute it and/or
    modify it under the terms of the GNU General Public License as
    published by the Free Software Foundation; either version 2 of the
    License, or (at your option) any later version.  See the file
    COPYING included with this distribution for more information.
*/

#include "StorageAdviser.h"

#include "Exceptions.h"
#include "TempDirectory.h"

#include "system/System.h"

#include <iostream>

long StorageAdviser::m_discPlanned = 0;
long StorageAdviser::m_memoryPlanned = 0;

StorageAdviser::Recommendation
StorageAdviser::recommend(Criteria criteria,
			  int minimumSize,
			  int maximumSize)
{
    std::cerr << "StorageAdviser::recommend: Criteria " << criteria 
              << ", minimumSize " << minimumSize
              << ", maximumSize " << maximumSize << std::endl;

    QString path = TempDirectory::getInstance()->getPath();
    int discFree = GetDiscSpaceMBAvailable(path.toLocal8Bit());
    int memoryFree, memoryTotal;
    GetRealMemoryMBAvailable(memoryFree, memoryTotal);

    if (discFree > m_discPlanned / 1024 + 1) {
        discFree -= m_discPlanned / 1024 + 1;
    } else if (discFree > 0) { // can also be -1 for unknown
        discFree = 0;
    }

    if (memoryFree > m_memoryPlanned / 1024 + 1) {
        memoryFree -= m_memoryPlanned / 1024 + 1;
    } else if (memoryFree > 0) { // can also be -1 for unknown
        memoryFree = 0;
    }

    std::cerr << "Disc space: " << discFree << ", memory free: " << memoryFree << ", memory total: " << memoryTotal << ", min " << minimumSize << ", max " << maximumSize << std::endl;

    //!!! We have a potentially serious problem here if multiple
    //recommendations are made in advance of any of the resulting
    //allocations, as the allocations that have been recommended for
    //won't be taken into account in subsequent recommendations.

    enum StorageStatus {
        Unknown,
        Insufficient,
        Marginal,
        Sufficient
    };

    StorageStatus memoryStatus = Unknown;
    StorageStatus discStatus = Unknown;

    int minmb = minimumSize / 1024 + 1;
    int maxmb = maximumSize / 1024 + 1;

    if (memoryFree == -1) memoryStatus = Unknown;
    else if (minmb > (memoryFree * 3) / 4) memoryStatus = Insufficient;
    else if (maxmb > (memoryFree * 3) / 4) memoryStatus = Marginal;
    else if (minmb > (memoryFree / 3)) memoryStatus = Marginal;
    else if (memoryTotal == -1 ||
             minmb > (memoryTotal / 10)) memoryStatus = Marginal;
    else if (memoryFree < memoryTotal / 4) memoryStatus = Marginal;
    else memoryStatus = Sufficient;

    if (discFree == -1) discStatus = Unknown;
    else if (minmb > (discFree * 3) / 4) discStatus = Insufficient;
    else if (maxmb > (discFree / 4)) discStatus = Marginal;
    else if (minmb > (discFree / 10)) discStatus = Marginal;
    else discStatus = Sufficient;

    std::cerr << "Memory status: " << memoryStatus << ", disc status "
              << discStatus << std::endl;

    int recommendation = NoRecommendation;

    if (memoryStatus == Insufficient || memoryStatus == Unknown) {

        recommendation |= UseDisc;

        if (discStatus == Insufficient && minmb > discFree) {
            throw InsufficientDiscSpace(path, minmb, discFree);
        }

        if (discStatus == Insufficient || discStatus == Marginal) {
            recommendation |= ConserveSpace;
        } else if (discStatus == Unknown && !(criteria & PrecisionCritical)) {
            recommendation |= ConserveSpace;
        } else {
            recommendation |= UseAsMuchAsYouLike;
        }

    } else if (memoryStatus == Marginal) {

        if (((criteria & SpeedCritical) ||
             (criteria & FrequentLookupLikely)) &&
            !(criteria & PrecisionCritical) &&
            !(criteria & LongRetentionLikely)) {

            // requirements suggest a preference for memory

            if (discStatus != Insufficient) {
                recommendation |= PreferMemory;
            } else {
                recommendation |= UseMemory;
            }

            recommendation |= ConserveSpace;

        } else {

            if (discStatus == Insufficient) {
                recommendation |= (UseMemory | ConserveSpace);
            } else if (discStatus == Marginal) {
                recommendation |= (PreferMemory | ConserveSpace);
            } else if (discStatus == Unknown) {
                recommendation |= (PreferDisc | ConserveSpace);
            } else {
                recommendation |= (UseDisc | UseAsMuchAsYouLike);
            }
        }    

    } else {

        if (discStatus == Insufficient) {
            recommendation |= (UseMemory | ConserveSpace);
        } else if (discStatus != Sufficient) {
            recommendation |= (PreferMemory | ConserveSpace);
        } else {

            if ((criteria & SpeedCritical) ||
                (criteria & FrequentLookupLikely)) {
                recommendation |= PreferMemory;
                if (criteria & PrecisionCritical) {
                    recommendation |= UseAsMuchAsYouLike;
                } else {
                    recommendation |= ConserveSpace;
                }
            } else {
                recommendation |= PreferDisc;
                recommendation |= UseAsMuchAsYouLike;
            }
        }
    }

    return Recommendation(recommendation);
}

void
StorageAdviser::notifyPlannedAllocation(AllocationArea area, int size)
{
    if (area == MemoryAllocation) m_memoryPlanned += size;
    else if (area == DiscAllocation) m_discPlanned += size;
//    std::cerr << "storage planned up: memory: " << m_memoryPlanned << ", disc "
//              << m_discPlanned << std::endl;
}

void
StorageAdviser::notifyDoneAllocation(AllocationArea area, int size)
{
    if (area == MemoryAllocation) {
        if (m_memoryPlanned > size) m_memoryPlanned -= size;
        else m_memoryPlanned = 0;
    } else if (area == DiscAllocation) {
        if (m_discPlanned > size) m_discPlanned -= size; 
        else m_discPlanned = 0;
    }
//    std::cerr << "storage planned down: memory: " << m_memoryPlanned << ", disc "
//              << m_discPlanned << std::endl;
}