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-rw-r--r--eth/downloader/queue.go416
1 files changed, 282 insertions, 134 deletions
diff --git a/eth/downloader/queue.go b/eth/downloader/queue.go
index 1b63a5ffb..eae567052 100644
--- a/eth/downloader/queue.go
+++ b/eth/downloader/queue.go
@@ -1,201 +1,349 @@
package downloader
import (
+ "errors"
"fmt"
- "math"
"sync"
"time"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/core/types"
- "gopkg.in/fatih/set.v0"
+ "gopkg.in/karalabe/cookiejar.v2/collections/prque"
)
+const (
+ blockCacheLimit = 4096 // Maximum number of blocks to cache before throttling the download
+)
+
+// fetchRequest is a currently running block retrieval operation.
+type fetchRequest struct {
+ Peer *peer // Peer to which the request was sent
+ Hashes map[common.Hash]int // Requested hashes with their insertion index (priority)
+ Time time.Time // Time when the request was made
+}
+
// queue represents hashes that are either need fetching or are being fetched
type queue struct {
- hashPool *set.Set
- fetchPool *set.Set
- blockHashes *set.Set
+ hashPool map[common.Hash]int // Pending hashes, mapping to their insertion index (priority)
+ hashQueue *prque.Prque // Priority queue of the block hashes to fetch
+ hashCounter int // Counter indexing the added hashes to ensure retrieval order
+
+ pendPool map[string]*fetchRequest // Currently pending block retrieval operations
+ pendCount int // Number of pending block fetches (to throttle the download)
- mu sync.Mutex
- fetching map[string]*chunk
+ blockPool map[common.Hash]int // Hash-set of the downloaded data blocks, mapping to cache indexes
+ blockCache []*types.Block // Downloaded but not yet delivered blocks
+ blockOffset int // Offset of the first cached block in the block-chain
- blockOffset int
- blocks []*types.Block
+ lock sync.RWMutex
}
-func newqueue() *queue {
+// newQueue creates a new download queue for scheduling block retrieval.
+func newQueue() *queue {
return &queue{
- hashPool: set.New(),
- fetchPool: set.New(),
- blockHashes: set.New(),
- fetching: make(map[string]*chunk),
+ hashPool: make(map[common.Hash]int),
+ hashQueue: prque.New(),
+ pendPool: make(map[string]*fetchRequest),
+ blockPool: make(map[common.Hash]int),
}
}
-func (c *queue) reset() {
- c.mu.Lock()
- defer c.mu.Unlock()
+// Reset clears out the queue contents.
+func (q *queue) Reset() {
+ q.lock.Lock()
+ defer q.lock.Unlock()
- c.resetNoTS()
+ q.hashPool = make(map[common.Hash]int)
+ q.hashQueue.Reset()
+ q.hashCounter = 0
+
+ q.pendPool = make(map[string]*fetchRequest)
+ q.pendCount = 0
+
+ q.blockPool = make(map[common.Hash]int)
+ q.blockOffset = 0
+ q.blockCache = nil
}
-func (c *queue) resetNoTS() {
- c.blockOffset = 0
- c.hashPool.Clear()
- c.fetchPool.Clear()
- c.blockHashes.Clear()
- c.blocks = nil
- c.fetching = make(map[string]*chunk)
+
+// Done checks if all the downloads have been retrieved, wiping the queue.
+func (q *queue) Done() {
+ q.lock.Lock()
+ defer q.lock.Unlock()
+
+ if len(q.blockCache) == 0 {
+ q.Reset()
+ }
}
-func (c *queue) size() int {
- return c.hashPool.Size() + c.blockHashes.Size() + c.fetchPool.Size()
+// Size retrieves the number of hashes in the queue, returning separately for
+// pending and already downloaded.
+func (q *queue) Size() (int, int) {
+ q.lock.RLock()
+ defer q.lock.RUnlock()
+
+ return len(q.hashPool), len(q.blockPool)
}
-// reserve a `max` set of hashes for `p` peer.
-func (c *queue) get(p *peer, max int) *chunk {
- c.mu.Lock()
- defer c.mu.Unlock()
+// Pending retrieves the number of hashes pending for retrieval.
+func (q *queue) Pending() int {
+ q.lock.RLock()
+ defer q.lock.RUnlock()
- // return nothing if the pool has been depleted
- if c.hashPool.Size() == 0 {
- return nil
- }
+ return q.hashQueue.Size()
+}
- limit := int(math.Min(float64(max), float64(c.hashPool.Size())))
- // Create a new set of hashes
- hashes, i := set.New(), 0
- c.hashPool.Each(func(v interface{}) bool {
- // break on limit
- if i == limit {
- return false
- }
- // skip any hashes that have previously been requested from the peer
- if p.ignored.Has(v) {
- return true
- }
+// InFlight retrieves the number of fetch requests currently in flight.
+func (q *queue) InFlight() int {
+ q.lock.RLock()
+ defer q.lock.RUnlock()
- hashes.Add(v)
- i++
+ return len(q.pendPool)
+}
+// Throttle checks if the download should be throttled (active block fetches
+// exceed block cache).
+func (q *queue) Throttle() bool {
+ q.lock.RLock()
+ defer q.lock.RUnlock()
+
+ return q.pendCount >= len(q.blockCache)-len(q.blockPool)
+}
+
+// Has checks if a hash is within the download queue or not.
+func (q *queue) Has(hash common.Hash) bool {
+ q.lock.RLock()
+ defer q.lock.RUnlock()
+
+ if _, ok := q.hashPool[hash]; ok {
+ return true
+ }
+ if _, ok := q.blockPool[hash]; ok {
return true
- })
- // if no hashes can be requested return a nil chunk
- if hashes.Size() == 0 {
- return nil
}
+ return false
+}
- // remove the fetchable hashes from hash pool
- c.hashPool.Separate(hashes)
- c.fetchPool.Merge(hashes)
+// Insert adds a set of hashes for the download queue for scheduling.
+func (q *queue) Insert(hashes []common.Hash) {
+ q.lock.Lock()
+ defer q.lock.Unlock()
- // Create a new chunk for the seperated hashes. The time is being used
- // to reset the chunk (timeout)
- chunk := &chunk{p, hashes, time.Now()}
- // register as 'fetching' state
- c.fetching[p.id] = chunk
+ // Insert all the hashes prioritized in the arrival order
+ for i, hash := range hashes {
+ index := q.hashCounter + i
- // create new chunk for peer
- return chunk
+ q.hashPool[hash] = index
+ q.hashQueue.Push(hash, float32(index)) // Highest gets schedules first
+ }
+ // Update the hash counter for the next batch of inserts
+ q.hashCounter += len(hashes)
}
-func (c *queue) has(hash common.Hash) bool {
- return c.hashPool.Has(hash) || c.fetchPool.Has(hash) || c.blockHashes.Has(hash)
+// GetHeadBlock retrieves the first block from the cache, or nil if it hasn't
+// been downloaded yet (or simply non existent).
+func (q *queue) GetHeadBlock() *types.Block {
+ q.lock.RLock()
+ defer q.lock.RUnlock()
+
+ if len(q.blockCache) == 0 {
+ return nil
+ }
+ return q.blockCache[0]
}
-func (c *queue) getBlock(hash common.Hash) *types.Block {
- c.mu.Lock()
- defer c.mu.Unlock()
+// GetBlock retrieves a downloaded block, or nil if non-existent.
+func (q *queue) GetBlock(hash common.Hash) *types.Block {
+ q.lock.RLock()
+ defer q.lock.RUnlock()
- if !c.blockHashes.Has(hash) {
+ // Short circuit if the block hasn't been downloaded yet
+ index, ok := q.blockPool[hash]
+ if !ok {
return nil
}
-
- for _, block := range c.blocks {
- if block.Hash() == hash {
- return block
- }
+ // Return the block if it's still available in the cache
+ if q.blockOffset <= index && index < q.blockOffset+len(q.blockCache) {
+ return q.blockCache[index-q.blockOffset]
}
return nil
}
-// deliver delivers a chunk to the queue that was requested of the peer
-func (c *queue) deliver(id string, blocks []*types.Block) (err error) {
- c.mu.Lock()
- defer c.mu.Unlock()
-
- chunk := c.fetching[id]
- // If the chunk was never requested simply ignore it
- if chunk != nil {
- delete(c.fetching, id)
- // check the length of the returned blocks. If the length of blocks is 0
- // we'll assume the peer doesn't know about the chain.
- if len(blocks) == 0 {
- // So we can ignore the blocks we didn't know about
- chunk.peer.ignored.Merge(chunk.hashes)
- }
+// TakeBlocks retrieves and permanently removes a batch of blocks from the cache.
+// The head parameter is required to prevent a race condition where concurrent
+// takes may fail parent verifications.
+func (q *queue) TakeBlocks(head *types.Block) types.Blocks {
+ q.lock.Lock()
+ defer q.lock.Unlock()
- // Add the blocks
- for i, block := range blocks {
- // See (1) for future limitation
- n := int(block.NumberU64()) - c.blockOffset
- if n > len(c.blocks) || n < 0 {
- // set the error and set the blocks which could be processed
- // abort the rest of the blocks (FIXME this could be improved)
- err = fmt.Errorf("received block which overflow (N=%v O=%v)", block.Number(), c.blockOffset)
- blocks = blocks[:i]
- break
- }
- c.blocks[n] = block
+ // Short circuit if the head block's different
+ if len(q.blockCache) == 0 || q.blockCache[0] != head {
+ return nil
+ }
+ // Otherwise accumulate all available blocks
+ var blocks types.Blocks
+ for _, block := range q.blockCache {
+ if block == nil {
+ break
}
- // seperate the blocks and the hashes
- blockHashes := chunk.fetchedHashes(blocks)
- // merge block hashes
- c.blockHashes.Merge(blockHashes)
- // Add back whatever couldn't be delivered
- c.hashPool.Merge(chunk.hashes)
- // Remove the hashes from the fetch pool
- c.fetchPool.Separate(chunk.hashes)
+ blocks = append(blocks, block)
+ delete(q.blockPool, block.Hash())
+ }
+ // Delete the blocks from the slice and let them be garbage collected
+ // without this slice trick the blocks would stay in memory until nil
+ // would be assigned to q.blocks
+ copy(q.blockCache, q.blockCache[len(blocks):])
+ for k, n := len(q.blockCache)-len(blocks), len(q.blockCache); k < n; k++ {
+ q.blockCache[k] = nil
}
+ q.blockOffset += len(blocks)
- return
+ return blocks
}
-func (c *queue) alloc(offset, size int) {
- c.mu.Lock()
- defer c.mu.Unlock()
+// Reserve reserves a set of hashes for the given peer, skipping any previously
+// failed download.
+func (q *queue) Reserve(p *peer, max int) *fetchRequest {
+ q.lock.Lock()
+ defer q.lock.Unlock()
- if c.blockOffset < offset {
- c.blockOffset = offset
+ // Short circuit if the pool has been depleted
+ if q.hashQueue.Empty() {
+ return nil
}
-
- // (1) XXX at some point we could limit allocation to memory and use the disk
- // to store future blocks.
- if len(c.blocks) < size {
- c.blocks = append(c.blocks, make([]*types.Block, size)...)
+ // Retrieve a batch of hashes, skipping previously failed ones
+ send := make(map[common.Hash]int)
+ skip := make(map[common.Hash]int)
+
+ for len(send) < max && !q.hashQueue.Empty() {
+ hash, priority := q.hashQueue.Pop()
+ if p.ignored.Has(hash) {
+ skip[hash.(common.Hash)] = int(priority)
+ } else {
+ send[hash.(common.Hash)] = int(priority)
+ }
+ }
+ // Merge all the skipped hashes back
+ for hash, index := range skip {
+ q.hashQueue.Push(hash, float32(index))
+ }
+ // Assemble and return the block download request
+ if len(send) == 0 {
+ return nil
}
+ request := &fetchRequest{
+ Peer: p,
+ Hashes: send,
+ Time: time.Now(),
+ }
+ q.pendPool[p.id] = request
+ q.pendCount += len(request.Hashes)
+
+ return request
}
-// puts puts sets of hashes on to the queue for fetching
-func (c *queue) put(hashes *set.Set) {
- c.mu.Lock()
- defer c.mu.Unlock()
+// Cancel aborts a fetch request, returning all pending hashes to the queue.
+func (q *queue) Cancel(request *fetchRequest) {
+ q.lock.Lock()
+ defer q.lock.Unlock()
- c.hashPool.Merge(hashes)
+ for hash, index := range request.Hashes {
+ q.hashQueue.Push(hash, float32(index))
+ }
+ delete(q.pendPool, request.Peer.id)
+ q.pendCount -= len(request.Hashes)
}
-type chunk struct {
- peer *peer
- hashes *set.Set
- itime time.Time
+// Expire checks for in flight requests that exceeded a timeout allowance,
+// canceling them and returning the responsible peers for penalization.
+func (q *queue) Expire(timeout time.Duration) []string {
+ q.lock.Lock()
+ defer q.lock.Unlock()
+
+ // Iterate over the expired requests and return each to the queue
+ peers := []string{}
+ for id, request := range q.pendPool {
+ if time.Since(request.Time) > timeout {
+ for hash, index := range request.Hashes {
+ q.hashQueue.Push(hash, float32(index))
+ }
+ q.pendCount -= len(request.Hashes)
+ peers = append(peers, id)
+ }
+ }
+ // Remove the expired requests from the pending pool
+ for _, id := range peers {
+ delete(q.pendPool, id)
+ }
+ return peers
}
-func (ch *chunk) fetchedHashes(blocks []*types.Block) *set.Set {
- fhashes := set.New()
+// Deliver injects a block retrieval response into the download queue.
+func (q *queue) Deliver(id string, blocks []*types.Block) (err error) {
+ q.lock.Lock()
+ defer q.lock.Unlock()
+
+ // Short circuit if the blocks were never requested
+ request := q.pendPool[id]
+ if request == nil {
+ return errors.New("no fetches pending")
+ }
+ delete(q.pendPool, id)
+
+ // Mark all the hashes in the request as non-pending
+ q.pendCount -= len(request.Hashes)
+
+ // If no blocks were retrieved, mark them as unavailable for the origin peer
+ if len(blocks) == 0 {
+ for hash, _ := range request.Hashes {
+ request.Peer.ignored.Add(hash)
+ }
+ }
+ // Iterate over the downloaded blocks and add each of them
+ errs := make([]error, 0)
for _, block := range blocks {
- fhashes.Add(block.Hash())
+ // Skip any blocks that fall outside the cache range
+ index := int(block.NumberU64()) - q.blockOffset
+ if index >= len(q.blockCache) || index < 0 {
+ //fmt.Printf("block cache overflown (N=%v O=%v, C=%v)", block.Number(), q.blockOffset, len(q.blockCache))
+ continue
+ }
+ // Skip any blocks that were not requested
+ hash := block.Hash()
+ if _, ok := request.Hashes[hash]; !ok {
+ errs = append(errs, fmt.Errorf("non-requested block %v", hash))
+ continue
+ }
+ // Otherwise merge the block and mark the hash block
+ q.blockCache[index] = block
+
+ delete(request.Hashes, hash)
+ delete(q.hashPool, hash)
+ q.blockPool[hash] = int(block.NumberU64())
}
- ch.hashes.Separate(fhashes)
+ // Return all failed fetches to the queue
+ for hash, index := range request.Hashes {
+ q.hashQueue.Push(hash, float32(index))
+ }
+ if len(errs) != 0 {
+ return fmt.Errorf("multiple failures: %v", errs)
+ }
+ return nil
+}
- return fhashes
+// Alloc ensures that the block cache is the correct size, given a starting
+// offset, and a memory cap.
+func (q *queue) Alloc(offset int) {
+ q.lock.Lock()
+ defer q.lock.Unlock()
+
+ if q.blockOffset < offset {
+ q.blockOffset = offset
+ }
+ size := len(q.hashPool)
+ if size > blockCacheLimit {
+ size = blockCacheLimit
+ }
+ if len(q.blockCache) < size {
+ q.blockCache = append(q.blockCache, make([]*types.Block, size-len(q.blockCache))...)
+ }
}