frozen editor while panning or zooming of the map

Stephan Knauss osm at stephans-server.de
Sun Sep 9 23:11:51 UTC 2018


Hello,

I sometimes suffer delays of 10-15s when panning or zooming the map.

I had the impression it started to become worse when tile serving was 
switched over to https, but switching back to http did not fully fix it.
With JOSM being updated in parallel all not that great to track down 
such issues. Just seeing in the terminal window large gaps between tile 
requests. Hiding imagery tiles always makes it fast. So it is certainly 
related.

So today I tried again to reproduce it, this time with YourKit Profiler 
connected.

I noticed some shorter delays, but couldn't fully reproduce the extreme 
delays.

Majority of time (about 60%) was spent in what I guess is tile loading:
HttpClient.java:91 
org.openstreetmap.josm.tools.HttpClient.connect(ProgressMonitor)

I have typically the two DG layers active sometimes also esri and bing 
to compare the images and alignment. With my large screen having 4k 
resolution, I might have a significant larger window visible than the 
average user.
I sometimes feared that mapbox might throttle the tile delivery. My 
connection itself is a fast 50 MBit link which typically is fast towards 
mapbox.

I then thought to make it a bit harder for JOSM and reduced the maximum 
connections per host down from 12 connections to 6 connections.

I got multiple seconds of frozen map now. After panning or zooming the 
view is frozen. Mouse still moves, but the line I am currently painting 
no longer follows the cursor. Just jumps back after five to ten seconds.

Now the majority of time is spent here:

HostLimitQueue.java:30 
org.openstreetmap.josm.data.cache.HostLimitQueue.poll(long, TimeUnit)

Can you please give some high-level explanation on how the GUI is 
connected to tile loading?

My expectation would be that tile loading happens in the background. In 
case of a blocked download (for whatever reason) my expectation would be 
that just the background tiles are not updated. panning, zooming or 
editing should not wait on it.
Is there a critical section somewhere which would be better not shared 
between the editor and tile loading?

How much personal details is recorded in the profiler snapshots? Would 
it help if I share one? Anyone more experienced interested in running a 
profiling session via skype?


If I read the call tree correctly, then below:
HttpClient.java:91 
org.openstreetmap.josm.tools.HttpClient.connect(ProgressMonitor)
the routines
HttpClient.java:149 <...> 
sun.net.www.protocol.https.HttpsURLConnectionImpl.getResponseCode()
and
HttpClient.java:149 <...> java.net.HttpURLConnection.getResponseCode()

use 40% of the time there. Do I get it right that this is only used for 
logging? Maybe only do this then in case log-level is at least info

### Eclipse Workspace Patch 1.0
#P JOSM
Index: src/org/openstreetmap/josm/tools/HttpClient.java
===================================================================
--- src/org/openstreetmap/josm/tools/HttpClient.java	(revision 14108)
+++ src/org/openstreetmap/josm/tools/HttpClient.java	(working copy)
@@ -144,13 +144,15 @@
              try {
                  connection.connect();
                  final boolean hasReason = reasonForRequest != null && 
!reasonForRequest.isEmpty();
-                Logging.info("{0} {1}{2} -> {3}{4}",
-                        requestMethod, url, hasReason ? (" (" + 
reasonForRequest + ')') : "",
-                        connection.getResponseCode(),
-                        connection.getContentLengthLong() > 0
-                                ? (" (" + 
Utils.getSizeString(connection.getContentLengthLong(), 
Locale.getDefault()) + ')')
-                                : ""
-                );
+                if (Logging.isLoggingEnabled(Logging.LEVEL_INFO)) {
+                    Logging.info("{0} {1}{2} -> {3}{4}",
+                            requestMethod, url, hasReason ? (" (" + 
reasonForRequest + ')') : "",
+                            connection.getResponseCode(),
+                            connection.getContentLengthLong() > 0
+                                    ? (" (" + 
Utils.getSizeString(connection.getContentLengthLong(), 
Locale.getDefault()) + ')')
+                                    : ""
+                    );
+                }
                  if (Logging.isDebugEnabled()) {
                      Logging.debug("RESPONSE: {0}", 
connection.getHeaderFields());
                  }



Stephan




More information about the josm-dev mailing list