From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.3.2 (2011-06-06) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: X-Spam-Status: No, score=-2.8 required=3.0 tests=ALL_TRUSTED,AWL,BAYES_00, URIBL_BLOCKED shortcircuit=no autolearn=unavailable version=3.3.2 X-Original-To: unicorn-public@bogomips.org Received: from localhost (dcvr.yhbt.net [127.0.0.1]) by dcvr.yhbt.net (Postfix) with ESMTP id E9DE11F7C2; Wed, 18 Feb 2015 09:36:00 +0000 (UTC) Date: Wed, 18 Feb 2015 09:36:00 +0000 From: Eric Wong To: unicorn-public@bogomips.org Cc: Steven Stewart-Gallus , Jesse Storimer Subject: [PATCH] explain 11 byte magic number for self-pipe Message-ID: <20150218093600.GA30065@dcvr.yhbt.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline List-Id: 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 015bd94..683eb82 100644 --- a/lib/unicorn/http_server.rb +++ b/lib/unicorn/http_server.rb @@ -370,6 +370,10 @@ class Unicorn::HttpServer # wait for a signal hander to wake us up and then consume the pipe def master_sleep(sec) IO.select([ @self_pipe[0] ], nil, nil, sec) or return + # 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: @self_pipe[0].kgio_tryread(11) end -- EW