Hi,
there have been quite some performance tuning measures on ptolemy:
(1) number of render processes has been reduced from 8/6 to 4
(2) Kolossos modified expire.rb to render low zoom tiles with low
probability
(3) indexes have been added to the DB for geometry,hstore and osm-id
(4) clustering
Is there a good way that we can monitor the results? Especially
(1) should be carefully tracked. I can see no significant changes
in IO throughput
http://munin.toolserver.org/OSM/ptolemy/iostat.html or IO
http://munin.toolserver.org/OSM/ptolemy/io_bytes_sd.html
and not even in postgres connections
http://munin.toolserver.org/OSM/ptolemy/postgres_connections_osm_mapnik.html
The load and CPU usage has been decreased a bit. My guess would
be that more processes would result in a better CPU utilization
(and thus faster overall rendering).
To monitor this we need two figures: (a) average tile rendering
time (per process) and (b) tiles rendered per second (by all
processes). Can we set up munin to track it?
BTW:
http://munin.toolserver.org/OSM/ptolemy/tirex_status_queued_requests.html has
not been updated for 13 h now,
how can that happen?
And another question: earlier, two slots have been reserved for
prio 1 queue requests (i.e. missing tiles). Is there a reserve
available currently? Otherwise one would have to wait in that
case.
Kind regards,
Kay