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authorgary rong <garyrong0905@gmail.com>2018-08-03 16:33:37 +0800
committerPéter Szilágyi <peterke@gmail.com>2018-08-03 16:33:37 +0800
commit51db5975cc5fb88db6a0dba1826b534fd4df29d7 (patch)
tree930f5a66d52c9bdcecd5596d7630fb48b0982cfd /consensus/ethash
parent70176cda0eedbb4ec9cde867e8f6cde63efa5a12 (diff)
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consensus/ethash: move remote agent logic to ethash internal (#15853)
* consensus/ethash: start remote ggoroutine to handle remote mining * consensus/ethash: expose remote miner api * consensus/ethash: expose submitHashrate api * miner, ethash: push empty block to sealer without waiting execution * consensus, internal: add getHashrate API for ethash * consensus: add three method for consensus interface * miner: expose consensus engine running status to miner * eth, miner: specify etherbase when miner created * miner: commit new work when consensus engine is started * consensus, miner: fix some logics * all: delete useless interfaces * consensus: polish a bit
Diffstat (limited to 'consensus/ethash')
-rw-r--r--consensus/ethash/algorithm_test.go1
-rw-r--r--consensus/ethash/api.go117
-rw-r--r--consensus/ethash/ethash.go132
-rw-r--r--consensus/ethash/ethash_test.go92
-rw-r--r--consensus/ethash/sealer.go149
5 files changed, 475 insertions, 16 deletions
diff --git a/consensus/ethash/algorithm_test.go b/consensus/ethash/algorithm_test.go
index f0c6465fd..e7625f7c0 100644
--- a/consensus/ethash/algorithm_test.go
+++ b/consensus/ethash/algorithm_test.go
@@ -730,6 +730,7 @@ func TestConcurrentDiskCacheGeneration(t *testing.T) {
go func(idx int) {
defer pend.Done()
ethash := New(Config{cachedir, 0, 1, "", 0, 0, ModeNormal})
+ defer ethash.Close()
if err := ethash.VerifySeal(nil, block.Header()); err != nil {
t.Errorf("proc %d: block verification failed: %v", idx, err)
}
diff --git a/consensus/ethash/api.go b/consensus/ethash/api.go
new file mode 100644
index 000000000..a04ea235d
--- /dev/null
+++ b/consensus/ethash/api.go
@@ -0,0 +1,117 @@
+// Copyright 2018 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package ethash
+
+import (
+ "errors"
+
+ "github.com/ethereum/go-ethereum/common"
+ "github.com/ethereum/go-ethereum/common/hexutil"
+ "github.com/ethereum/go-ethereum/core/types"
+)
+
+var errEthashStopped = errors.New("ethash stopped")
+
+// API exposes ethash related methods for the RPC interface.
+type API struct {
+ ethash *Ethash // Make sure the mode of ethash is normal.
+}
+
+// GetWork returns a work package for external miner.
+//
+// The work package consists of 3 strings:
+// result[0] - 32 bytes hex encoded current block header pow-hash
+// result[1] - 32 bytes hex encoded seed hash used for DAG
+// result[2] - 32 bytes hex encoded boundary condition ("target"), 2^256/difficulty
+func (api *API) GetWork() ([3]string, error) {
+ if api.ethash.config.PowMode != ModeNormal && api.ethash.config.PowMode != ModeTest {
+ return [3]string{}, errors.New("not supported")
+ }
+
+ var (
+ workCh = make(chan [3]string, 1)
+ errc = make(chan error, 1)
+ )
+
+ select {
+ case api.ethash.fetchWorkCh <- &sealWork{errc: errc, res: workCh}:
+ case <-api.ethash.exitCh:
+ return [3]string{}, errEthashStopped
+ }
+
+ select {
+ case work := <-workCh:
+ return work, nil
+ case err := <-errc:
+ return [3]string{}, err
+ }
+}
+
+// SubmitWork can be used by external miner to submit their POW solution.
+// It returns an indication if the work was accepted.
+// Note either an invalid solution, a stale work a non-existent work will return false.
+func (api *API) SubmitWork(nonce types.BlockNonce, hash, digest common.Hash) bool {
+ if api.ethash.config.PowMode != ModeNormal && api.ethash.config.PowMode != ModeTest {
+ return false
+ }
+
+ var errc = make(chan error, 1)
+
+ select {
+ case api.ethash.submitWorkCh <- &mineResult{
+ nonce: nonce,
+ mixDigest: digest,
+ hash: hash,
+ errc: errc,
+ }:
+ case <-api.ethash.exitCh:
+ return false
+ }
+
+ err := <-errc
+ return err == nil
+}
+
+// SubmitHashrate can be used for remote miners to submit their hash rate.
+// This enables the node to report the combined hash rate of all miners
+// which submit work through this node.
+//
+// It accepts the miner hash rate and an identifier which must be unique
+// between nodes.
+func (api *API) SubmitHashRate(rate hexutil.Uint64, id common.Hash) bool {
+ if api.ethash.config.PowMode != ModeNormal && api.ethash.config.PowMode != ModeTest {
+ return false
+ }
+
+ var done = make(chan struct{}, 1)
+
+ select {
+ case api.ethash.submitRateCh <- &hashrate{done: done, rate: uint64(rate), id: id}:
+ case <-api.ethash.exitCh:
+ return false
+ }
+
+ // Block until hash rate submitted successfully.
+ <-done
+
+ return true
+}
+
+// GetHashrate returns the current hashrate for local CPU miner and remote miner.
+func (api *API) GetHashrate() uint64 {
+ return uint64(api.ethash.Hashrate())
+}
diff --git a/consensus/ethash/ethash.go b/consensus/ethash/ethash.go
index f79dd6c36..0cb3059b9 100644
--- a/consensus/ethash/ethash.go
+++ b/consensus/ethash/ethash.go
@@ -33,7 +33,9 @@ import (
"unsafe"
mmap "github.com/edsrzf/mmap-go"
+ "github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/consensus"
+ "github.com/ethereum/go-ethereum/core/types"
"github.com/ethereum/go-ethereum/log"
"github.com/ethereum/go-ethereum/metrics"
"github.com/ethereum/go-ethereum/rpc"
@@ -389,6 +391,30 @@ type Config struct {
PowMode Mode
}
+// mineResult wraps the pow solution parameters for the specified block.
+type mineResult struct {
+ nonce types.BlockNonce
+ mixDigest common.Hash
+ hash common.Hash
+
+ errc chan error
+}
+
+// hashrate wraps the hash rate submitted by the remote sealer.
+type hashrate struct {
+ id common.Hash
+ ping time.Time
+ rate uint64
+
+ done chan struct{}
+}
+
+// sealWork wraps a seal work package for remote sealer.
+type sealWork struct {
+ errc chan error
+ res chan [3]string
+}
+
// Ethash is a consensus engine based on proof-of-work implementing the ethash
// algorithm.
type Ethash struct {
@@ -403,15 +429,25 @@ type Ethash struct {
update chan struct{} // Notification channel to update mining parameters
hashrate metrics.Meter // Meter tracking the average hashrate
+ // Remote sealer related fields
+ workCh chan *types.Block // Notification channel to push new work to remote sealer
+ resultCh chan *types.Block // Channel used by mining threads to return result
+ fetchWorkCh chan *sealWork // Channel used for remote sealer to fetch mining work
+ submitWorkCh chan *mineResult // Channel used for remote sealer to submit their mining result
+ fetchRateCh chan chan uint64 // Channel used to gather submitted hash rate for local or remote sealer.
+ submitRateCh chan *hashrate // Channel used for remote sealer to submit their mining hashrate
+
// The fields below are hooks for testing
shared *Ethash // Shared PoW verifier to avoid cache regeneration
fakeFail uint64 // Block number which fails PoW check even in fake mode
fakeDelay time.Duration // Time delay to sleep for before returning from verify
- lock sync.Mutex // Ensures thread safety for the in-memory caches and mining fields
+ lock sync.Mutex // Ensures thread safety for the in-memory caches and mining fields
+ closeOnce sync.Once // Ensures exit channel will not be closed twice.
+ exitCh chan chan error // Notification channel to exiting backend threads
}
-// New creates a full sized ethash PoW scheme.
+// New creates a full sized ethash PoW scheme and starts a background thread for remote mining.
func New(config Config) *Ethash {
if config.CachesInMem <= 0 {
log.Warn("One ethash cache must always be in memory", "requested", config.CachesInMem)
@@ -423,19 +459,43 @@ func New(config Config) *Ethash {
if config.DatasetDir != "" && config.DatasetsOnDisk > 0 {
log.Info("Disk storage enabled for ethash DAGs", "dir", config.DatasetDir, "count", config.DatasetsOnDisk)
}
- return &Ethash{
- config: config,
- caches: newlru("cache", config.CachesInMem, newCache),
- datasets: newlru("dataset", config.DatasetsInMem, newDataset),
- update: make(chan struct{}),
- hashrate: metrics.NewMeter(),
+ ethash := &Ethash{
+ config: config,
+ caches: newlru("cache", config.CachesInMem, newCache),
+ datasets: newlru("dataset", config.DatasetsInMem, newDataset),
+ update: make(chan struct{}),
+ hashrate: metrics.NewMeter(),
+ workCh: make(chan *types.Block),
+ resultCh: make(chan *types.Block),
+ fetchWorkCh: make(chan *sealWork),
+ submitWorkCh: make(chan *mineResult),
+ fetchRateCh: make(chan chan uint64),
+ submitRateCh: make(chan *hashrate),
+ exitCh: make(chan chan error),
}
+ go ethash.remote()
+ return ethash
}
// NewTester creates a small sized ethash PoW scheme useful only for testing
// purposes.
func NewTester() *Ethash {
- return New(Config{CachesInMem: 1, PowMode: ModeTest})
+ ethash := &Ethash{
+ config: Config{PowMode: ModeTest},
+ caches: newlru("cache", 1, newCache),
+ datasets: newlru("dataset", 1, newDataset),
+ update: make(chan struct{}),
+ hashrate: metrics.NewMeter(),
+ workCh: make(chan *types.Block),
+ resultCh: make(chan *types.Block),
+ fetchWorkCh: make(chan *sealWork),
+ submitWorkCh: make(chan *mineResult),
+ fetchRateCh: make(chan chan uint64),
+ submitRateCh: make(chan *hashrate),
+ exitCh: make(chan chan error),
+ }
+ go ethash.remote()
+ return ethash
}
// NewFaker creates a ethash consensus engine with a fake PoW scheme that accepts
@@ -489,6 +549,22 @@ func NewShared() *Ethash {
return &Ethash{shared: sharedEthash}
}
+// Close closes the exit channel to notify all backend threads exiting.
+func (ethash *Ethash) Close() error {
+ var err error
+ ethash.closeOnce.Do(func() {
+ // Short circuit if the exit channel is not allocated.
+ if ethash.exitCh == nil {
+ return
+ }
+ errc := make(chan error)
+ ethash.exitCh <- errc
+ err = <-errc
+ close(ethash.exitCh)
+ })
+ return err
+}
+
// cache tries to retrieve a verification cache for the specified block number
// by first checking against a list of in-memory caches, then against caches
// stored on disk, and finally generating one if none can be found.
@@ -561,14 +637,44 @@ func (ethash *Ethash) SetThreads(threads int) {
// Hashrate implements PoW, returning the measured rate of the search invocations
// per second over the last minute.
+// Note the returned hashrate includes local hashrate, but also includes the total
+// hashrate of all remote miner.
func (ethash *Ethash) Hashrate() float64 {
- return ethash.hashrate.Rate1()
+ // Short circuit if we are run the ethash in normal/test mode.
+ if ethash.config.PowMode != ModeNormal && ethash.config.PowMode != ModeTest {
+ return ethash.hashrate.Rate1()
+ }
+ var res = make(chan uint64, 1)
+
+ select {
+ case ethash.fetchRateCh <- res:
+ case <-ethash.exitCh:
+ // Return local hashrate only if ethash is stopped.
+ return ethash.hashrate.Rate1()
+ }
+
+ // Gather total submitted hash rate of remote sealers.
+ return ethash.hashrate.Rate1() + float64(<-res)
}
-// APIs implements consensus.Engine, returning the user facing RPC APIs. Currently
-// that is empty.
+// APIs implements consensus.Engine, returning the user facing RPC APIs.
func (ethash *Ethash) APIs(chain consensus.ChainReader) []rpc.API {
- return nil
+ // In order to ensure backward compatibility, we exposes ethash RPC APIs
+ // to both eth and ethash namespaces.
+ return []rpc.API{
+ {
+ Namespace: "eth",
+ Version: "1.0",
+ Service: &API{ethash},
+ Public: true,
+ },
+ {
+ Namespace: "ethash",
+ Version: "1.0",
+ Service: &API{ethash},
+ Public: true,
+ },
+ }
}
// SeedHash is the seed to use for generating a verification cache and the mining
diff --git a/consensus/ethash/ethash_test.go b/consensus/ethash/ethash_test.go
index 31116da43..ccdd30fb0 100644
--- a/consensus/ethash/ethash_test.go
+++ b/consensus/ethash/ethash_test.go
@@ -23,7 +23,10 @@ import (
"os"
"sync"
"testing"
+ "time"
+ "github.com/ethereum/go-ethereum/common"
+ "github.com/ethereum/go-ethereum/common/hexutil"
"github.com/ethereum/go-ethereum/core/types"
)
@@ -32,6 +35,7 @@ func TestTestMode(t *testing.T) {
head := &types.Header{Number: big.NewInt(1), Difficulty: big.NewInt(100)}
ethash := NewTester()
+ defer ethash.Close()
block, err := ethash.Seal(nil, types.NewBlockWithHeader(head), nil)
if err != nil {
t.Fatalf("failed to seal block: %v", err)
@@ -52,6 +56,7 @@ func TestCacheFileEvict(t *testing.T) {
}
defer os.RemoveAll(tmpdir)
e := New(Config{CachesInMem: 3, CachesOnDisk: 10, CacheDir: tmpdir, PowMode: ModeTest})
+ defer e.Close()
workers := 8
epochs := 100
@@ -77,3 +82,90 @@ func verifyTest(wg *sync.WaitGroup, e *Ethash, workerIndex, epochs int) {
e.VerifySeal(nil, head)
}
}
+
+func TestRemoteSealer(t *testing.T) {
+ ethash := NewTester()
+ defer ethash.Close()
+ api := &API{ethash}
+ if _, err := api.GetWork(); err != errNoMiningWork {
+ t.Error("expect to return an error indicate there is no mining work")
+ }
+
+ head := &types.Header{Number: big.NewInt(1), Difficulty: big.NewInt(100)}
+ block := types.NewBlockWithHeader(head)
+
+ // Push new work.
+ ethash.Seal(nil, block, nil)
+
+ var (
+ work [3]string
+ err error
+ )
+ if work, err = api.GetWork(); err != nil || work[0] != block.HashNoNonce().Hex() {
+ t.Error("expect to return a mining work has same hash")
+ }
+
+ if res := api.SubmitWork(types.BlockNonce{}, block.HashNoNonce(), common.Hash{}); res {
+ t.Error("expect to return false when submit a fake solution")
+ }
+
+ // Push new block with same block number to replace the original one.
+ head = &types.Header{Number: big.NewInt(1), Difficulty: big.NewInt(1000)}
+ block = types.NewBlockWithHeader(head)
+ ethash.Seal(nil, block, nil)
+
+ if work, err = api.GetWork(); err != nil || work[0] != block.HashNoNonce().Hex() {
+ t.Error("expect to return the latest pushed work")
+ }
+
+ // Push block with higher block number.
+ newHead := &types.Header{Number: big.NewInt(2), Difficulty: big.NewInt(100)}
+ newBlock := types.NewBlockWithHeader(newHead)
+ ethash.Seal(nil, newBlock, nil)
+
+ if res := api.SubmitWork(types.BlockNonce{}, block.HashNoNonce(), common.Hash{}); res {
+ t.Error("expect to return false when submit a stale solution")
+ }
+}
+
+func TestHashRate(t *testing.T) {
+ var (
+ ethash = NewTester()
+ api = &API{ethash}
+ hashrate = []hexutil.Uint64{100, 200, 300}
+ expect uint64
+ ids = []common.Hash{common.HexToHash("a"), common.HexToHash("b"), common.HexToHash("c")}
+ )
+
+ defer ethash.Close()
+
+ if tot := ethash.Hashrate(); tot != 0 {
+ t.Error("expect the result should be zero")
+ }
+
+ for i := 0; i < len(hashrate); i += 1 {
+ if res := api.SubmitHashRate(hashrate[i], ids[i]); !res {
+ t.Error("remote miner submit hashrate failed")
+ }
+ expect += uint64(hashrate[i])
+ }
+ if tot := ethash.Hashrate(); tot != float64(expect) {
+ t.Error("expect total hashrate should be same")
+ }
+}
+
+func TestClosedRemoteSealer(t *testing.T) {
+ ethash := NewTester()
+ // Make sure exit channel has been listened
+ time.Sleep(1 * time.Second)
+ ethash.Close()
+
+ api := &API{ethash}
+ if _, err := api.GetWork(); err != errEthashStopped {
+ t.Error("expect to return an error to indicate ethash is stopped")
+ }
+
+ if res := api.SubmitHashRate(hexutil.Uint64(100), common.HexToHash("a")); res {
+ t.Error("expect to return false when submit hashrate to a stopped ethash")
+ }
+}
diff --git a/consensus/ethash/sealer.go b/consensus/ethash/sealer.go
index b5e742d8b..a9449d406 100644
--- a/consensus/ethash/sealer.go
+++ b/consensus/ethash/sealer.go
@@ -18,11 +18,13 @@ package ethash
import (
crand "crypto/rand"
+ "errors"
"math"
"math/big"
"math/rand"
"runtime"
"sync"
+ "time"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/consensus"
@@ -30,6 +32,11 @@ import (
"github.com/ethereum/go-ethereum/log"
)
+var (
+ errNoMiningWork = errors.New("no mining work available yet")
+ errInvalidSealResult = errors.New("invalid or stale proof-of-work solution")
+)
+
// Seal implements consensus.Engine, attempting to find a nonce that satisfies
// the block's difficulty requirements.
func (ethash *Ethash) Seal(chain consensus.ChainReader, block *types.Block, stop <-chan struct{}) (*types.Block, error) {
@@ -45,7 +52,6 @@ func (ethash *Ethash) Seal(chain consensus.ChainReader, block *types.Block, stop
}
// Create a runner and the multiple search threads it directs
abort := make(chan struct{})
- found := make(chan *types.Block)
ethash.lock.Lock()
threads := ethash.threads
@@ -64,12 +70,16 @@ func (ethash *Ethash) Seal(chain consensus.ChainReader, block *types.Block, stop
if threads < 0 {
threads = 0 // Allows disabling local mining without extra logic around local/remote
}
+ // Push new work to remote sealer
+ if ethash.workCh != nil {
+ ethash.workCh <- block
+ }
var pend sync.WaitGroup
for i := 0; i < threads; i++ {
pend.Add(1)
go func(id int, nonce uint64) {
defer pend.Done()
- ethash.mine(block, id, nonce, abort, found)
+ ethash.mine(block, id, nonce, abort, ethash.resultCh)
}(i, uint64(ethash.rand.Int63()))
}
// Wait until sealing is terminated or a nonce is found
@@ -78,7 +88,7 @@ func (ethash *Ethash) Seal(chain consensus.ChainReader, block *types.Block, stop
case <-stop:
// Outside abort, stop all miner threads
close(abort)
- case result = <-found:
+ case result = <-ethash.resultCh:
// One of the threads found a block, abort all others
close(abort)
case <-ethash.update:
@@ -150,3 +160,136 @@ search:
// during sealing so it's not unmapped while being read.
runtime.KeepAlive(dataset)
}
+
+// remote starts a standalone goroutine to handle remote mining related stuff.
+func (ethash *Ethash) remote() {
+ var (
+ works = make(map[common.Hash]*types.Block)
+ rates = make(map[common.Hash]hashrate)
+ currentWork *types.Block
+ )
+
+ // getWork returns a work package for external miner.
+ //
+ // The work package consists of 3 strings:
+ // result[0], 32 bytes hex encoded current block header pow-hash
+ // result[1], 32 bytes hex encoded seed hash used for DAG
+ // result[2], 32 bytes hex encoded boundary condition ("target"), 2^256/difficulty
+ getWork := func() ([3]string, error) {
+ var res [3]string
+ if currentWork == nil {
+ return res, errNoMiningWork
+ }
+ res[0] = currentWork.HashNoNonce().Hex()
+ res[1] = common.BytesToHash(SeedHash(currentWork.NumberU64())).Hex()
+
+ // Calculate the "target" to be returned to the external sealer.
+ n := big.NewInt(1)
+ n.Lsh(n, 255)
+ n.Div(n, currentWork.Difficulty())
+ n.Lsh(n, 1)
+ res[2] = common.BytesToHash(n.Bytes()).Hex()
+
+ // Trace the seal work fetched by remote sealer.
+ works[currentWork.HashNoNonce()] = currentWork
+ return res, nil
+ }
+
+ // submitWork verifies the submitted pow solution, returning
+ // whether the solution was accepted or not (not can be both a bad pow as well as
+ // any other error, like no pending work or stale mining result).
+ submitWork := func(nonce types.BlockNonce, mixDigest common.Hash, hash common.Hash) bool {
+ // Make sure the work submitted is present
+ block := works[hash]
+ if block == nil {
+ log.Info("Work submitted but none pending", "hash", hash)
+ return false
+ }
+
+ // Verify the correctness of submitted result.
+ header := block.Header()
+ header.Nonce = nonce
+ header.MixDigest = mixDigest
+ if err := ethash.VerifySeal(nil, header); err != nil {
+ log.Warn("Invalid proof-of-work submitted", "hash", hash, "err", err)
+ return false
+ }
+
+ // Make sure the result channel is created.
+ if ethash.resultCh == nil {
+ log.Warn("Ethash result channel is empty, submitted mining result is rejected")
+ return false
+ }
+
+ // Solutions seems to be valid, return to the miner and notify acceptance.
+ select {
+ case ethash.resultCh <- block.WithSeal(header):
+ delete(works, hash)
+ return true
+ default:
+ log.Info("Work submitted is stale", "hash", hash)
+ return false
+ }
+ }
+
+ ticker := time.NewTicker(5 * time.Second)
+ defer ticker.Stop()
+
+ for {
+ select {
+ case block := <-ethash.workCh:
+ if currentWork != nil && block.ParentHash() != currentWork.ParentHash() {
+ // Start new round mining, throw out all previous work.
+ works = make(map[common.Hash]*types.Block)
+ }
+ // Update current work with new received block.
+ // Note same work can be past twice, happens when changing CPU threads.
+ currentWork = block
+
+ case work := <-ethash.fetchWorkCh:
+ // Return current mining work to remote miner.
+ miningWork, err := getWork()
+ if err != nil {
+ work.errc <- err
+ } else {
+ work.res <- miningWork
+ }
+
+ case result := <-ethash.submitWorkCh:
+ // Verify submitted PoW solution based on maintained mining blocks.
+ if submitWork(result.nonce, result.mixDigest, result.hash) {
+ result.errc <- nil
+ } else {
+ result.errc <- errInvalidSealResult
+ }
+
+ case result := <-ethash.submitRateCh:
+ // Trace remote sealer's hash rate by submitted value.
+ rates[result.id] = hashrate{rate: result.rate, ping: time.Now()}
+ close(result.done)
+
+ case req := <-ethash.fetchRateCh:
+ // Gather all hash rate submitted by remote sealer.
+ var total uint64
+ for _, rate := range rates {
+ // this could overflow
+ total += rate.rate
+ }
+ req <- total
+
+ case <-ticker.C:
+ // Clear stale submitted hash rate.
+ for id, rate := range rates {
+ if time.Since(rate.ping) > 10*time.Second {
+ delete(rates, id)
+ }
+ }
+
+ case errc := <-ethash.exitCh:
+ // Exit remote loop if ethash is closed and return relevant error.
+ errc <- nil
+ log.Trace("Ethash remote sealer is exiting")
+ return
+ }
+ }
+}