From c7c82f1b44e07ad0906dde563cce46ea87b6fc83 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?P=C3=A9ter=20Szil=C3=A1gyi?= Date: Fri, 22 Jul 2016 17:55:46 +0300 Subject: [PATCH] eth/downloader: fix the stall checks/drops during sync --- eth/downloader/downloader.go | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/eth/downloader/downloader.go b/eth/downloader/downloader.go index 01c0818a0..a10253b8e 100644 --- a/eth/downloader/downloader.go +++ b/eth/downloader/downloader.go @@ -1555,7 +1555,14 @@ func (d *Downloader) fetchParts(errCancel error, deliveryCh chan dataPack, deliv // Check for fetch request timeouts and demote the responsible peers for pid, fails := range expire() { if peer := d.peers.Peer(pid); peer != nil { - if fails > 1 { + // If a lot of retrieval elements expired, we might have overestimated the remote peer or perhaps + // ourselves. Only reset to minimal throughput but don't drop just yet. If even the minimal times + // out that sync wise we need to get rid of the peer. + // + // The reason the minimum threshold is 2 is because the downloader tries to estimate the bandwidth + // and latency of a peer separately, which requires pushing the measures capacity a bit and seeing + // how response times reacts, to it always requests one more than the minimum (i.e. min 2). + if fails > 2 { glog.V(logger.Detail).Infof("%s: %s delivery timeout", peer, strings.ToLower(kind)) setIdle(peer, 0) } else {