|author||Eric Wong <firstname.lastname@example.org>||2011-04-29 16:01:35 -0700|
|committer||Eric Wong <email@example.com>||2011-04-29 16:01:35 -0700|
It seems people are still confused about it...
2 files changed, 24 insertions, 8 deletions
@@ -1,13 +1,32 @@
-= Tuning Unicorn
+= Tuning \Unicorn
-Unicorn performance is generally as good as a (mostly) Ruby web server
+\Unicorn performance is generally as good as a (mostly) Ruby web server
can provide. Most often the performance bottleneck is in the web
application running on Unicorn rather than Unicorn itself.
-== Unicorn Configuration
+== \Unicorn Configuration
See Unicorn::Configurator for details on the config file format.
+* worker_processes should be scaled to the number of processes your
+ backend system(s) can support. DO NOT scale it to the number of
+ external network clients your application expects to be serving.
+ \Unicorn is NOT for serving slow clients, that is the job of nginx.
+* worker_processes should be *at* *least* the number of CPU cores on
+ a dedicated server. If your application has occasionally slow
+ responses that are /not/ CPU-intensive, you may increase this to
+ workaround those inefficiencies.
+* worker_processes may be increased for Unicorn::OobGC users to provide
+ more consistent response times.
+* Never, ever, increase worker_processes to the point where the system
+ runs out of physical memory and hits swap. Production servers should
+ never see heavy swap activity.
* Setting a very low value for the :backlog parameter in "listen"
directives can allow failover to happen more quickly if your
cluster is configured for it.
@@ -42,11 +61,6 @@ See Unicorn::Configurator for details on the config file format.
have them unbuffered (File#sync = true) or they are
record(line)-buffered in userspace before any writes.
-* worker_processes should be scaled to the number of processes your
- backend system(s) can support. DO NOT scale it to the number of
- external network clients your application expects to be serving.
- Unicorn is NOT for serving slow clients, that is the job of nginx.
== Kernel Parameters (Linux sysctl)
WARNING: Do not change system parameters unless you know what you're doing!
diff --git a/lib/unicorn/configurator.rb b/lib/unicorn/configurator.rb
index bed3abe..b6ad022 100644
@@ -8,6 +8,8 @@ require 'logger'
# example configuration files. An example config file for use with
# nginx is also available at
+# See the link:/TUNING.html document for more information on tuning unicorn.