Optimized PoS header downloader (ledgerwatch#4775)

* optimized PoS header downloader

* removed println

* comments

* ops

* Restore schedulePoSDownload params + simplify

Co-authored-by: giuliorebuffo <giuliorebuffo@system76-pc.localdomain>
Co-authored-by: yperbasis <andrey.ashikhmin@gmail.com>

eth/stagedsync/stage_headers.go

@@ -305,9 +305,8 @@ func startHandlingForkChoice(
 
 	if header == nil {
 		log.Info(fmt.Sprintf("[%s] Fork choice missing header with hash %x", s.LogPrefix(), headerHash))
-		hashToDownload := headerHash
 		cfg.hd.SetPoSDownloaderTip(headerHash)
-		schedulePoSDownload(requestId, hashToDownload, 0 /* header height is unknown, setting to 0 */, s, cfg)
+		schedulePoSDownload(requestId, headerHash, 0 /* header height is unknown, setting to 0 */, s, cfg)
 		return &privateapi.PayloadStatus{Status: remote.EngineStatus_SYNCING}, nil
 	}
 
@@ -487,10 +486,8 @@ func handleNewPayload(
 	}
 	if parent == nil {
 		log.Info(fmt.Sprintf("[%s] New payload missing parent", s.LogPrefix()))
-		hashToDownload := header.ParentHash
-		heightToDownload := headerNumber - 1
 		cfg.hd.SetPoSDownloaderTip(headerHash)
-		schedulePoSDownload(requestId, hashToDownload, heightToDownload, s, cfg)
+		schedulePoSDownload(requestId, header.ParentHash, headerNumber-1, s, cfg)
 		return &privateapi.PayloadStatus{Status: remote.EngineStatus_SYNCING}, nil
 	}
 
@@ -629,7 +626,7 @@ func schedulePoSDownload(
 
 	cfg.hd.SetRequestId(requestId)
 	cfg.hd.SetHeaderToDownloadPoS(hashToDownload, heightToDownload)
-	cfg.hd.SetPOSSync(true) // This needs to be called afrer SetHeaderToDownloadPOS because SetHeaderToDownloadPOS sets `posAnchor` member field which is used by ProcessHeadersPOS
+	cfg.hd.SetPOSSync(true) // This needs to be called after SetHeaderToDownloadPOS because SetHeaderToDownloadPOS sets `posAnchor` member field which is used by ProcessHeadersPOS
 
 	//nolint
 	headerCollector := etl.NewCollector(s.LogPrefix(), cfg.tmpdir, etl.NewSortableBuffer(etl.BufferOptimalSize))

turbo/engineapi/fork_validator.go

@@ -228,7 +228,6 @@ func (fv *ForkValidator) ValidatePayload(tx kv.RwTx, header *types.Header, body
 	// if the block is not in range of maxForkDepth from head then we do not validate it.
 	if abs64(int64(fv.currentHeight)-header.Number.Int64()) > maxForkDepth {
 		status = remote.EngineStatus_ACCEPTED
-		fmt.Println("not in range")
 		return
 	}
 	// Let's assemble the side fork backwards

turbo/stages/headerdownload/header_algos.go

@@ -437,7 +437,7 @@ func (hd *HeaderDownload) requestMoreHeadersForPOS(currentTime time.Time) (timeo
 	request = &HeaderRequest{
 		Anchor:  anchor,
 		Hash:    anchor.parentHash,
-		Number:  0, // Since posAnchor may be an estimate, do not specify it here
+		Number:  anchor.blockHeight - 1,
 		Length:  192,
 		Skip:    0,
 		Reverse: true,