From 0d9b834624f5c74200c7d7f5ba42b0d8557c674b Mon Sep 17 00:00:00 2001 From: Eric Wong Date: Wed, 18 Feb 2015 09:22:56 +0000 Subject: explain 11 byte magic number for self-pipe Oops, this should've been explained long ago but apparently not. In response to a comment on http://www.sitepoint.com/the-self-pipe-trick-explained/ > Does anybody know why both unicorn and foreman read 11 bytes from > self-pipe? Unfortunately I couldn't find a way to comment on the site on a JavaScript-free browser nor does it seem possible without registering. Again, anybody can send plain-text mail to: unicorn-public@bogomips.org No registration, no real name policy, no terms-of-service, just plain-text. Feel free to use Tor, mixmaster or any anonymity service, too. --- lib/unicorn/http_server.rb | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/lib/unicorn/http_server.rb b/lib/unicorn/http_server.rb index 509fb36..329c5bf 100644 --- a/lib/unicorn/http_server.rb +++ b/lib/unicorn/http_server.rb @@ -389,6 +389,10 @@ class Unicorn::HttpServer # wait for a signal hander to wake us up and then consume the pipe def master_sleep(sec) + # 11 bytes is the maximum string length which can be embedded within + # the Ruby itself and not require a separate malloc (on 32-bit MRI 1.9+). + # Most reads are only one byte here and uncommon, so it's not worth a + # persistent buffer, either: IO.select([ SELF_PIPE[0] ], nil, nil, sec) or return SELF_PIPE[0].kgio_tryread(11) end -- cgit v1.2.3-24-ge0c7