diff --git a/remotefilelog/fileserverclient.py b/remotefilelog/fileserverclient.py
--- a/remotefilelog/fileserverclient.py
+++ b/remotefilelog/fileserverclient.py
@@ -9,6 +9,7 @@
 
 import hashlib, os, time, io, struct
 import itertools
+import threading
 
 from mercurial.i18n import _
 from mercurial.node import hex, bin, nullid
@@ -220,29 +221,26 @@
 def _getfiles(
     remote, receivemissing, progresstick, missed, idmap, step):
     remote._callstream("getfiles")
-    i = 0
     pipeo = shallowutil.trygetattr(remote, ('_pipeo', 'pipeo'))
     pipei = shallowutil.trygetattr(remote, ('_pipei', 'pipei'))
-    while i < len(missed):
-        # issue a batch of requests
-        start = i
-        end = min(len(missed), start + step)
-        i = end
-        for missingid in missed[start:end]:
-            # issue new request
+
+    def writer():
+        for missingid in missed:
             versionid = missingid[-40:]
             file = idmap[missingid]
             sshrequest = "%s%s\n" % (versionid, file)
             pipeo.write(sshrequest)
         pipeo.flush()
+    writerthread = threading.Thread(target=writer)
+    writerthread.start()
 
-        # receive batch results
-        for missingid in missed[start:end]:
-            versionid = missingid[-40:]
-            file = idmap[missingid]
-            receivemissing(pipei, file, versionid)
-            progresstick()
+    for missingid in missed:
+        versionid = missingid[-40:]
+        file = idmap[missingid]
+        receivemissing(pipei, file, versionid)
+        progresstick()
 
+    writerthread.join()
     # End the command
     pipeo.write('\n')
     pipeo.flush()