From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 111696 invoked by alias); 21 Mar 2017 07:29:16 -0000 Mailing-List: contact cygwin-help@cygwin.com; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: cygwin-owner@cygwin.com Mail-Followup-To: cygwin@cygwin.com Received: (qmail 111638 invoked by uid 89); 21 Mar 2017 07:29:10 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.9 required=5.0 tests=BAYES_00,FREEMAIL_FROM,RCVD_IN_DNSWL_NONE,SPF_PASS autolearn=ham version=3.3.2 spammy=million, Misch, misch, Noah X-HELO: mail-wr0-f169.google.com Received: from mail-wr0-f169.google.com (HELO mail-wr0-f169.google.com) (209.85.128.169) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with ESMTP; Tue, 21 Mar 2017 07:29:06 +0000 Received: by mail-wr0-f169.google.com with SMTP id u48so106242898wrc.0 for ; Tue, 21 Mar 2017 00:29:07 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-transfer-encoding; bh=RZE7CJHwgZfLkC1HY0f9e3lEjBWxG7buemtXnRQP61M=; b=IAN3KtU4ymTgvCCeh+p8ZAX46OCDfAOdDcjxzeSk4Thzg5zgXmjF9Vo4NiHQTpavcQ +jzTHiC6TonCLKpXPFrGol/cZUaKKoXNtSyOXx9FLauKH08/siojHK/rVeceqIOVS0Ga py7Jz7p7QMN0b+31/1H/fn2RFNcX3cEiItF1S8vu/JJ472CcfxJG2s6jwwJjbhEAhv8Z 59VqQ/J5q3q3iBvAIEpsNjpcDx4zyshNGB3ukFEk6L1iXu1CwHboekqOlTCrPGrhmOXE f7PCGgbZojJXrmGdDOue4lT4M7RaKbhO6Tb+28vtHII7JHHddhSfV63jypoS4dNxAqj+ z8XA== X-Gm-Message-State: AFeK/H2cDNCMD/VipqelOdeLRORNHcINQVNGSWOSiZIVHxjxvA65hOnIVLrwpsA2LmrXqA== X-Received: by 10.223.134.157 with SMTP id 29mr28340011wrx.33.1490081345755; Tue, 21 Mar 2017 00:29:05 -0700 (PDT) Received: from [172.21.188.226] ([62.154.173.198]) by smtp.googlemail.com with ESMTPSA id w12sm10155905wra.21.2017.03.21.00.29.04 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 21 Mar 2017 00:29:04 -0700 (PDT) Subject: Re: cygserver - Postgres Multiple connection Load Testing - Inifinte Loop To: cygwin@cygwin.com References: <200408030333.i733XEXn023894@mx3.redhat.com> <20040803100612.GP31522@cygbert.vinschen.de> <20170321025614.GA2100214@tornado.leadboat.com> From: Marco Atzeri Message-ID: <8fd6c531-0fdc-3c81-c932-e601cddec714@gmail.com> Date: Tue, 21 Mar 2017 07:29:00 -0000 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.8.0 MIME-Version: 1.0 In-Reply-To: <20170321025614.GA2100214@tornado.leadboat.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit X-IsSubscribed: yes X-SW-Source: 2017-03/txt/msg00219.txt.bz2 On 21/03/2017 03:56, Noah Misch wrote: > On Tue, Aug 03, 2004 at 12:06:12PM +0200, Corinna Vinschen wrote: >> On Aug 2 20:33, sarbx-cygwin6344@mailblocks.com wrote: >>> This time around, cygserver does not eat CPU. But after 5 to 6 >>> concurrent >>> connections nothing seem to work, looks kind of hung. There is no >>> activity in the Postgres >>> log file. Opening a new database connection also hangs. There is no >>> activity on the machine. > >> Any chance to create a simple testcase which uncovers that behaviour >> without involving a whole database system? > > Attached test program reproduces it on Cygwin 2.7.0, Cygwin 1.7.5, and a few > intermediate versions. The program creates sixteen processes that each > perform a tight loop over the following: same on x86_64 2.8.0-0.1 > > - select one of four semaphores > - reduce semaphore's value from 1 to 0 ("lock" it) > - raise semaphore's value from 0 to 1 ("unlock" it) > > On GNU/Linux, AIX, and Solaris, the processes keep busy and finish one million > lock/unlock cycles apiece in a few minutes. On Cygwin, they hang within a few > seconds and under one hundred cycles apiece. At that point, cygserver is > unresponsive to other clients; for example, "strace /bin/true", opening a new > Cygwin terminal, "cat /proc/sysvipc/sem" and "cygserver -S" all hang. In most > tests, cygserver was not consuming CPU while unresponsive. confirmed > Thanks, > nm > Regards Marco -- Problem reports: http://cygwin.com/problems.html FAQ: http://cygwin.com/faq/ Documentation: http://cygwin.com/docs.html Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple