From: Eric Wong <email@example.com> To: firstname.lastname@example.org Subject: Re: raindrops tests fail on smp, fork is to blame Date: Fri, 22 Jun 2012 15:29:20 -0700 Message-ID: <20120622222920.GA32552@dcvr.yhbt.net> (raw) In-Reply-To: <CAAB-Kc=wfr0EQJ7h=YJ1J5NmAogEYbXmzy9f9Q6H21+-mntJ9w@mail.gmail.com> Hleb Valoshka <email@example.com> wrote: > Hello! > > Raindrops build hangs on debian's build servers, but not on my local > box. This occurs when tests are run under ruby1.9.1. You can see > example of build log in . It took a lot of time to understand that > the main difference between build and my box is number of CPUs: > debian's servers are smp, my kvm box had only 1 cpu. > > Today I decided to start kvm with option -smp 2, and voila! build > hung. The more tests with fork() you have the higher probability build > will hang. When all tests are enabled, the probability of hang is > about 100% when tests are run by gem2deb (it loads all test files > simultaneously) and about 5-10% with "make test". When test_concurrect > from test_middleware.rb and test_incr_shared, test_incr_decr and > test_evaporate_with_fork from test_raindrops.rb are disabled build > runs without hangs. > > Any ideas? This is only on GNU/kFreeBSD, right? I managed to reproduce this on my older Debian GNU/kFreeBSD 6.0 KVM instance, too. I suspect it's a bad interaction with the internal timer thread of Ruby 1.9 and fork(). Probably some mutex is held when the fork() happens and attempting to acquire it in the child process causes a deadlock. Even without loading raindrops, the following code locks up for me with ruby1.9.1 220.127.116.11-2 on my Debian GNU/kFreeBSD 6.0 instance: 1000.times do pid = fork do 1 + 1 end Process.waitpid2(pid) end Can you try it on 1.9.3-p194 on your newer wheezy/sid install? I think some libc folks will need to be roped into this fix this.
next prev parent reply index Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top 2012-06-22 21:06 Hleb Valoshka 2012-06-22 22:29 ` Eric Wong [this message] 2012-06-23 11:59 ` Hleb Valoshka
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style List information: https://yhbt.net/raindrops/ * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=20120622222920.GA32552@dcvr.yhbt.net \ --firstname.lastname@example.org \ --email@example.com \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: link
raindrops RubyGem user+dev discussion/patches/pulls/bugs/help Archives are clonable: git clone --mirror https://yhbt.net/raindrops-public git clone --mirror http://ou63pmih66umazou.onion/raindrops-public Example config snippet for mirrors Newsgroups are available over NNTP: nntp://news.public-inbox.org/inbox.comp.lang.ruby.raindrops nntp://ou63pmih66umazou.onion/inbox.comp.lang.ruby.raindrops note: .onion URLs require Tor: https://www.torproject.org/ AGPL code for this site: git clone https://public-inbox.org/public-inbox.git