iic.cc

来自「M5,一个功能强大的多处理器系统模拟器.很多针对处理器架构,性能的研究都使用它作」· CC 代码 · 共 707 行 · 第 1/2 页

    assert(tag_ptr->isValid());

    DPRINTF(Cache, "Replacing %x in IIC: %s\n",
            regenerateBlkAddr(tag_ptr->tag,0),
            tag_ptr->isDirty() ? "writeback" : "clean");
    /* write back replaced block data */
    if (tag_ptr && (tag_ptr->isValid())) {
        replacements[0]++;
        totalRefs += tag_ptr->refCount;
        ++sampledRefs;
        tag_ptr->refCount = 0;

        if (tag_ptr->isDirty()) {
/*	    PacketPtr writeback =
                buildWritebackReq(regenerateBlkAddr(tag_ptr->tag, 0),
                                  tag_ptr->req->asid, tag_ptr->xc, blkSize,
                                  tag_ptr->data,
                                  tag_ptr->size);
*/
            Request *writebackReq = new Request(regenerateBlkAddr(tag_ptr->tag, 0),
                                           blkSize, 0);
            PacketPtr writeback = new Packet(writebackReq, MemCmd::Writeback,
                                             -1);
            writeback->allocate();
            memcpy(writeback->getPtr<uint8_t>(), tag_ptr->data, blkSize);

            writebacks.push_back(writeback);
        }
    }

    // free the data blocks
    for (int i = 0; i < tag_ptr->numData; ++i) {
        data_ptr = tag_ptr->data_ptr[i];
        assert(dataReferenceCount[data_ptr]>0);
        if (--dataReferenceCount[data_ptr] == 0) {
            freeDataBlock(data_ptr);
        }
    }
    freeTag(tag_ptr);
}

unsigned long
IIC::getFreeDataBlock(PacketList & writebacks)
{
    struct IICTag *tag_ptr;
    unsigned long data_ptr;

    tag_ptr = NULL;
    /* find data block */
    while (blkFreelist.empty()) {
        freeReplacementBlock(writebacks);
    }

    data_ptr = blkFreelist.front();
    blkFreelist.pop_front();
    DPRINTF(IICMore,"Found free data at %d\n",data_ptr);
    return data_ptr;
}



IICTag*
IIC::getFreeTag(int set, PacketList & writebacks)
{
    unsigned long tag_index;
    IICTag *tag_ptr;
    // Add new tag
    tag_ptr = sets[set].findFree();
    // if no free in primary, and secondary exists
    if (!tag_ptr && numSecondary) {
        // need to spill a tag into secondary storage
        while (freelist == tagNull) {
            // get replacements until one is in secondary
            freeReplacementBlock(writebacks);
        }

        tag_index = freelist;
        freelist = tagStore[freelist].chain_ptr;
        freeSecond--;

        assert(tag_index != tagNull);
        tagSwap(tag_index, sets[set].tags[assoc-1] - tagStore);
        tagStore[tag_index].chain_ptr = sets[set].chain_ptr;
        sets[set].chain_ptr = tag_index;

        tag_ptr = sets[set].tags[assoc-1];
    }
    DPRINTF(IICMore,"Found free tag at %d\n",tag_ptr - tagStore);
    tagsInUse++;
    if (!warmedUp && tagsInUse.value() >= warmupBound) {
        warmedUp = true;
        warmupCycle = curTick;
    }

    return tag_ptr;
}

void
IIC::freeTag(IICTag *tag_ptr)
{
    unsigned long tag_index, tmp_index;
    // Fix tag_ptr
    if (tag_ptr) {
        // we have a tag to clear
        DPRINTF(IICMore,"Freeing Tag for %x\n",
                regenerateBlkAddr(tag_ptr->tag,0));
        tagsInUse--;
        tag_ptr->status = 0;
        tag_ptr->numData = 0;
        tag_ptr->re = NULL;
        tag_index = tag_ptr - tagStore;
        if (tag_index >= primaryBound) {
            // tag_ptr points to secondary store
            assert(tag_index < tagNull); // remove this?? egh
            if (tag_ptr->chain_ptr == tagNull) {
                // need to fix chain list
                unsigned tmp_set = hash(tag_ptr->tag << tagShift);
                if (sets[tmp_set].chain_ptr == tag_index) {
                    sets[tmp_set].chain_ptr = tagNull;
                } else {
                    tmp_index = sets[tmp_set].chain_ptr;
                    while (tmp_index != tagNull
                           && tagStore[tmp_index].chain_ptr != tag_index) {
                        tmp_index = tagStore[tmp_index].chain_ptr;
                    }
                    assert(tmp_index != tagNull);
                    tagStore[tmp_index].chain_ptr = tagNull;
                }
                tag_ptr->chain_ptr = freelist;
                freelist = tag_index;
                freeSecond++;
            } else {
                // copy next chained entry to this tag location
                tmp_index = tag_ptr->chain_ptr;
                tagSwap(tmp_index, tag_index);
                tagStore[tmp_index].chain_ptr = freelist;
                freelist = tmp_index;
                freeSecond++;
            }
        } else {
            // tag_ptr in primary hash table
            assert(tag_index < primaryBound);
            tag_ptr->status = 0;
            unsigned tmp_set = hash(tag_ptr->tag << tagShift);
            if (sets[tmp_set].chain_ptr != tagNull) { // collapse chain
                tmp_index = sets[tmp_set].chain_ptr;
                tagSwap(tag_index, tmp_index);
                tagStore[tmp_index].chain_ptr = freelist;
                freelist = tmp_index;
                freeSecond++;
                sets[tmp_set].chain_ptr = tag_ptr->chain_ptr;
                sets[tmp_set].moveToTail(tag_ptr);
            }
        }
    }
}

void
IIC::freeDataBlock(unsigned long data_ptr)
{
    assert(dataReferenceCount[data_ptr] == 0);
    DPRINTF(IICMore, "Freeing data at %d\n", data_ptr);
    blkFreelist.push_front(data_ptr);
}

/** Use a simple modulo hash. */
#define SIMPLE_HASH 0

unsigned
IIC::hash(Addr addr) const {
#if SIMPLE_HASH
    return extractTag(addr) % iic_hash_size;
#else
    Addr tag, mask, x, y;
    tag = extractTag(addr);
    mask = hashSets-1; /* assumes iic_hash_size is a power of 2 */
    x = tag & mask;
    y = (tag >> (int)(::log((double)hashSets)/::log((double)2))) & mask;
    assert (x < hashSets && y < hashSets);
    return x ^ y;
#endif
}


void
IICSet::moveToHead(IICTag *tag)
{
    if (tags[0] == tag)
        return;

    // write 'next' block into blks[i], moving up from MRU toward LRU
    // until we overwrite the block we moved to head.

    // start by setting up to write 'blk' into blks[0]
    int i = 0;
    IICTag *next = tag;

    do {
        assert(i < assoc);
        // swap blks[i] and next
        IICTag *tmp = tags[i];
        tags[i] = next;
        next = tmp;
        ++i;
    } while (next != tag);
}

void
IICSet::moveToTail(IICTag *tag)
{
    if (tags[assoc-1] == tag)
        return;

    // write 'next' block into blks[i], moving up from MRU toward LRU
    // until we overwrite the block we moved to head.

    // start by setting up to write 'blk' into blks[0]
    int i = assoc - 1;
    IICTag *next = tag;

    do {
        assert(i >= 0);
        // swap blks[i] and next
        IICTag *tmp = tags[i];
        tags[i] = next;
        next = tmp;
        --i;
    } while (next != tag);
}

void
IIC::tagSwap(unsigned long index1, unsigned long index2)
{
    DPRINTF(IIC,"Swapping tag[%d]=%x for tag[%d]=%x\n",index1,
            tagStore[index1].tag<<tagShift, index2,
            tagStore[index2].tag<<tagShift);
    IICTag tmp_tag;
    tmp_tag = tagStore[index1];
    tagStore[index1] = tagStore[index2];
    tagStore[index2] = tmp_tag;
    if (tagStore[index1].isValid())
        repl->fixTag(tagStore[index1].re, index2, index1);
    if (tagStore[index2].isValid())
        repl->fixTag(tagStore[index2].re, index1, index2);
}


IICTag *
IIC::secondaryChain(Addr tag, unsigned long chain_ptr,
                    int *_depth) const
{
    int depth = 0;
    while (chain_ptr != tagNull) {
        DPRINTF(IIC,"Searching secondary at %d for %x\n", chain_ptr,
                tag<<tagShift);
        if (tagStore[chain_ptr].tag == tag &&
            (tagStore[chain_ptr].isValid())) {
            *_depth = depth;
            return &tagStore[chain_ptr];
        }
        depth++;
        chain_ptr = tagStore[chain_ptr].chain_ptr;
    }
    *_depth = depth;
    return NULL;
}

void
IIC::invalidateBlk(IIC::BlkType *tag_ptr)
{
    if (tag_ptr) {
        for (int i = 0; i < tag_ptr->numData; ++i) {
            dataReferenceCount[tag_ptr->data_ptr[i]]--;
            if (dataReferenceCount[tag_ptr->data_ptr[i]] == 0) {
                freeDataBlock(tag_ptr->data_ptr[i]);
            }
        }
        repl->removeEntry(tag_ptr->re);
        freeTag(tag_ptr);
    }
}

void
IIC::readData(IICTag *blk, uint8_t *data)
{
    assert(blk->size <= trivialSize || blk->numData > 0);
    int data_size = blk->size;
    if (data_size > trivialSize) {
        for (int i = 0; i < blk->numData; ++i){
            memcpy(data+i*subSize,
                   &(dataBlks[blk->data_ptr[i]][0]),
                   (data_size>subSize)?subSize:data_size);
            data_size -= subSize;
        }
    } else {
        memcpy(data,blk->trivialData,data_size);
    }
}

void
IIC::writeData(IICTag *blk, uint8_t *write_data, int size,
               PacketList & writebacks)
{
    DPRINTF(IIC, "Writing %d bytes to %x\n", size,
            blk->tag<<tagShift);
    // Find the number of subblocks needed, (round up)
    int num_subs = (size + (subSize -1))/subSize;
    if (size <= trivialSize) {
        num_subs = 0;
    }
    assert(num_subs <= numSub);
    if (num_subs > blk->numData) {
        // need to allocate more data blocks
        for (int i = blk->numData; i < num_subs; ++i){
            blk->data_ptr[i] = getFreeDataBlock(writebacks);
            dataReferenceCount[blk->data_ptr[i]] += 1;
        }
    } else if (num_subs < blk->numData){
        // can free data blocks
        for (int i=num_subs; i < blk->numData; ++i){
            // decrement reference count and compare to zero
            if (--dataReferenceCount[blk->data_ptr[i]] == 0) {
                freeDataBlock(blk->data_ptr[i]);
            }
        }
    }

    blk->numData = num_subs;
    blk->size = size;
    assert(size <= trivialSize || blk->numData > 0);
    if (size > trivialSize){
        for (int i = 0; i < blk->numData; ++i){
            memcpy(&dataBlks[blk->data_ptr[i]][0], write_data + i*subSize,
                   (size>subSize)?subSize:size);
            size -= subSize;
        }
    } else {
        memcpy(blk->trivialData,write_data,size);
    }
}


void
IIC::cleanupRefs()
{
    for (int i = 0; i < numTags; ++i) {
        if (tagStore[i].isValid()) {
            totalRefs += tagStore[i].refCount;
            ++sampledRefs;
        }
    }
}