X-Spam-Check-By: sourceware.org Date: Thu, 18 May 2006 00:04:57 -0400 (EDT) From: Igor Peshansky Reply-To: cygwin AT cygwin DOT com To: "Bryan D. Thomas" cc: cygwin AT cygwin DOT com Subject: Re: "fork problem" debugging In-Reply-To: <20060518023929.65449.qmail@web31310.mail.mud.yahoo.com> Message-ID: References: <20060518023929 DOT 65449 DOT qmail AT web31310 DOT mail DOT mud DOT yahoo DOT com> MIME-Version: 1.0 Content-Type: MULTIPART/MIXED; BOUNDARY="-559023410-1254324197-1147925097=:19815" Mailing-List: contact cygwin-help AT cygwin DOT com; run by ezmlm Precedence: bulk List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: cygwin-owner AT cygwin DOT com Mail-Followup-To: cygwin AT cygwin DOT com Delivered-To: mailing list cygwin AT cygwin DOT com ---559023410-1254324197-1147925097=:19815 Content-Type: TEXT/PLAIN; charset=US-ASCII On Wed, 17 May 2006, Bryan D. Thomas wrote: > I'm taking the risk of conflating several different > issues into one. On the other hand, this might be a > useful synthesis to help us bottom out on "fork > problems" so that we can turn a snapshot into a stable > release[1]? I've been plagued by these problems for a while (since you didn't provide full links in your message, I don't know whether you cited my message among them without a lot of cutting-and-pasting). I would like to help, but all information I have at this point is rather negative... One definite data point is that unloading and reloading just Cygwin1.dll (by exiting all Cygwin processes) fixes the problem for me (until the next time I run that resource-intensive script that reproduces the problem). > I've been trying to figure out strace incantations. > Hopefully someone more wizardly can help? Is strace > the best/only attack vector on this? I haven't found the strace to be all that useful, especially because the information printed in the strace doesn't reflect what's actually happening. The errno value is bogus (from inspecting the code). I have a patch (attached) that makes it print out more of the seemingly relevant information (pretty verbosely, basically dumping the whole pinfo structure plus printing the Windows error code) whenever a fork error occurs, but I haven't been able to follow through on actually using that information to debug the problem. > In [2] Torfinn Ottesen wrote: > > I find that my loops are OK until after about 80 > > cases, each loop increases my memory usage by about > > 3.2 MB > > I am aware of the following information: > [3],[4],[5] > > I have strace but do not know what to do with it > > I wonder if some strace like [6] would help? > > Perhaps someone could suggest a helpful "cheatsheet" of what we might > want to focus on in strace output of these processes? > > If it would be helpful to run strace against the processes in the > weather.sh fork example[7] , or in the nonsense testcase example[8] > ...what should the command line be, and what would we be looking for in > output? > > In [2], Larry Hall wrote: > > Sounds to me like the situation you found closely mirrors the behavior > > the MS KB article describes. I think it's worthwhile for you to > > experiment with the workaround proposed to see if it helps. It would > > be beneficial if you reported any results you saw back to this list. > > Torfinn, any luck on SharedSection parameter tweaking > per the MS KB? I'm not Torfinn, but I can say that I've been running with SharedSection=2048,6144,1024 (double my original values), which had no noticeable effect on the frequency of the fork errors (i.e., I still get them reproducibly). > http://sourceware.org/ml/cygwin/ > [1] 2006-05/msg00402.html > [2] 2006-05/msg00127.html > [3] 2006-04/msg00390.html > [4] 2005-09/msg00945.html > [5] http://support.microsoft.com/kb/824422 > http://sourceware.org/ml/cygwin/ > [6] 2006-05/msg00364.html > [7] 2006-04/msg00718.html > [8] 2006-05/msg00422.html Sorry I couldn't be of more help, but perhaps the info printed in the patch gives someone some idea... Igor -- http://cs.nyu.edu/~pechtcha/ |\ _,,,---,,_ pechtcha AT cs DOT nyu DOT edu | igor AT watson DOT ibm DOT com ZZZzz /,`.-'`' -. ;-;;,_ Igor Peshansky, Ph.D. (name changed!) |,4- ) )-,_. ,\ ( `'-' old name: Igor Pechtchanski '---''(_/--' `-'\_) fL a.k.a JaguaR-R-R-r-r-r-.-.-. Meow! "Las! je suis sot... -Mais non, tu ne l'es pas, puisque tu t'en rends compte." 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