path: root/doc/src/manual/cowboy_websocket.asciidoc
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authorLoïc Hoguin <[email protected]>2019-12-04 11:17:34 +0100
committerLoïc Hoguin <[email protected]>2020-01-06 12:58:14 +0100
commitdb0d6f8d254f2cc01bd458dc41969e0b96991cc3 (patch)
tree5d77236bc703223fcb36e45cbf3de72de1763d50 /doc/src/manual/cowboy_websocket.asciidoc
parent592029070dea7c1f7b85d465e250ef6842e1a46b (diff)
Use active,N
This reduces the number of times we need to ask for more packets, and as a result we get a fairly large boost in performance, especially with HTTP/1.1. Unfortunately this makes Cowboy require at least Erlang/OTP 21.3+ because the ssl application did not have active,N. For simplicity the version required will be Erlang/OTP 22+. In addition this change improves hibernate handling in cowboy_websocket. Hibernate will now work for HTTP/2 transport as well, and stray or unrelated messages will no longer cancel hibernate (the process will handle the message and go back into hibernation). Thanks go to Stressgrid for benchmarking an early version of this commit: https://stressgrid.com/blog/cowboy_performance_part_2/
Diffstat (limited to 'doc/src/manual/cowboy_websocket.asciidoc')
1 files changed, 12 insertions, 0 deletions
diff --git a/doc/src/manual/cowboy_websocket.asciidoc b/doc/src/manual/cowboy_websocket.asciidoc
index a11ca18..5b1558c 100644
--- a/doc/src/manual/cowboy_websocket.asciidoc
+++ b/doc/src/manual/cowboy_websocket.asciidoc
@@ -198,6 +198,7 @@ Cowboy does it automatically for you.
opts() :: #{
+ active_n => pos_integer(),
compress => boolean(),
deflate_opts => cow_ws:deflate_opts()
idle_timeout => timeout(),
@@ -221,6 +222,16 @@ init(Req, State) ->
The default value is given next to the option name:
+active_n (100)::
+The number of packets Cowboy will request from the socket at once.
+This can be used to tweak the performance of the server. Higher
+values reduce the number of times Cowboy need to request more
+packets from the port driver at the expense of potentially
+higher memory being used.
+This option does not apply to Websocket over HTTP/2.
compress (false)::
Whether to enable the Websocket frame compression
@@ -274,6 +285,7 @@ normal circumstances if necessary.
== Changelog
+* *2.8*: The `active_n` option was added.
* *2.7*: The commands based interface has been documented.
The old interface is now deprecated.
* *2.7*: The command `shutdown_reason` was introduced.