Change filesystem concurrency to number of cpus

Makes the EventEmitter warning show up less often, and avoids running potentially 100s or 1000s of chunkStore.get() calls concurrently in _verifyPieces

2 files changed, 6 insertions, 4 deletions

diff --git a/lib/torrent.js b/lib/torrent.js
index 970eab4..db3bebe 100644
--- a/lib/torrent.js
+++ b/lib/torrent.js
@@ -3,6 +3,7 @@
 const addrToIPPort = require('addr-to-ip-port')
 const BitField = require('bitfield').default
 const ChunkStoreWriteStream = require('chunk-store-stream/write')
+const cpus = require('cpus')
 const debug = require('debug')('webtorrent:torrent')
 const Discovery = require('torrent-discovery')
 const EventEmitter = require('events').EventEmitter
@@ -19,13 +20,13 @@ const parseTorrent = require('parse-torrent')
 const path = require('path')
 const Piece = require('torrent-piece')
 const pump = require('pump')
+const queueMicrotask = require('queue-microtask')
 const randomIterate = require('random-iterate')
 const sha1 = require('simple-sha1')
 const speedometer = require('speedometer')
 const utMetadata = require('ut_metadata')
-const utPex = require('ut_pex') // browser exclude
 const utp = require('utp-native') // browser exclude
-const queueMicrotask = require('queue-microtask')
+const utPex = require('ut_pex') // browser exclude
 
 const File = require('./file')
 const Peer = require('./peer')
@@ -44,8 +45,8 @@ const PIPELINE_MAX_DURATION = 1
 const RECHOKE_INTERVAL = 10000 // 10 seconds
 const RECHOKE_OPTIMISTIC_DURATION = 2 // 30 seconds
 
-// IndexedDB chunk stores used in the browser benefit from maximum concurrency
-const FILESYSTEM_CONCURRENCY = process.browser ? Infinity : 2
+// IndexedDB chunk stores used in the browser benefit from high concurrency
+const FILESYSTEM_CONCURRENCY = process.browser ? cpus().length : 2
 
 const RECONNECT_WAIT = [1000, 5000, 15000]
 
diff --git a/package.json b/package.json
index d660477..851696d 100644
--- a/package.json
+++ b/package.json
@@ -42,6 +42,7 @@
     "bittorrent-protocol": "^3.2.0",
     "chrome-net": "^3.3.4",
     "chunk-store-stream": "^4.2.0",
+    "cpus": "^1.0.3",
     "create-torrent": "^4.4.4",
     "debug": "^4.3.1",
     "end-of-stream": "^1.4.4",