1. devstack
  2. Commit 8cf9acd577a30bf9e6a54a9d82b9b7fc9ae769fb
Browse code

Tune apache connection limits down

We are facing memory pressure in gate testing. Apache is fairly large so
tune its connection limits down to try and squeeze out more useable
memory. THis should be fine for dev envs, also tlsproxy is not enabled
by default so we can check that this tuning works well on a subset of
jobs before making it default everywhere.

Data comparisons done with gate-tempest-dsvm-neutron-full-ubuntu-xenial
jobs.

Old: http://logs.openstack.org/37/447037/2/check/gate-tempest-dsvm-neutron-full-ubuntu-xenial/721fc6f/logs/screen-peakmem_tracker.txt.gz
PID %MEM RSS PPID TIME NLWP WCHAN COMMAND
20504 0.2 16660 19589 00:00:00 34 - /usr/sbin/apache2 -k start
20505 0.2 16600 19589 00:00:00 34 - /usr/sbin/apache2 -k start
20672 0.2 16600 19589 00:00:00 34 - /usr/sbin/apache2 -k start
20503 0.1 14388 19589 00:00:00 34 - /usr/sbin/apache2 -k start
19589 0.1 9964 1 00:00:00 1 - /usr/sbin/apache2 -k start
Total RSS: 74212

New: http://logs.openstack.org/41/446741/1/check/gate-tempest-dsvm-neutron-full-ubuntu-xenial/fa4d2e6/logs/screen-peakmem_tracker.txt.gz
PID %MEM RSS PPID TIME NLWP WCHAN COMMAND
8036 0.1 15316 8018 00:00:01 34 - /usr/sbin/apache2 -k start
8037 0.1 15228 8018 00:00:01 34 - /usr/sbin/apache2 -k start
8018 0.1 8584 1 00:00:00 1 - /usr/sbin/apache2 -k start
Total RSS: 39128

Note RSS here is in KB. Total difference is 35084KB or about
34MB. Not the biggest change, but we seem to be functional and it
almost halves the apache overhead.

Change-Id: If82fa347db140021197a215113df4ce38fb4fd17

Clark Boylan authored on 2017/03/17 06:06:58
Showing 1 changed files
lib/tls
History View file @ 8cf9acd
... ... 
@@ -457,29 +457,30 @@ function tune_apache_connections {
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 # MaxClients: maximum number of simultaneous client connections
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 # MaxRequestsPerChild: maximum number of requests a server process serves
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 #
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-# The apache defaults are too conservative if we want reliable tempest
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-# testing. Bump these values up from ~400 max clients to 1024 max clients.
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+# We want to be memory thrifty so tune down apache to allow 256 total
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+# connections. This should still be plenty for a dev env yet lighter than
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+# apache defaults.
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 <IfModule mpm_worker_module>
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 # Note that the next three conf values must be changed together.
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 # MaxClients = ServerLimit * ThreadsPerChild
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-ServerLimit          32
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+ServerLimit           8
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 ThreadsPerChild      32
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-MaxClients         1024
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-StartServers          3
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-MinSpareThreads      96
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-MaxSpareThreads     192
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+MaxClients          256
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+StartServers          2
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+MinSpareThreads      32
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+MaxSpareThreads      96
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 ThreadLimit          64
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 MaxRequestsPerChild   0
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 </IfModule>
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 <IfModule mpm_event_module>
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 # Note that the next three conf values must be changed together.
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 # MaxClients = ServerLimit * ThreadsPerChild
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-ServerLimit          32
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+ServerLimit           8
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 ThreadsPerChild      32
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-MaxClients         1024
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-StartServers          3
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-MinSpareThreads      96
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-MaxSpareThreads     192
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+MaxClients          256
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+StartServers          2
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+MinSpareThreads      32
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+MaxSpareThreads      96
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 ThreadLimit          64
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 MaxRequestsPerChild   0
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 </IfModule>