On Fri, 25 Sep 2015 18:58:57 +0200, Marco Atzeri wrote:
>> "Bad file descriptor" just arose recently in another problem
>> https://cygwin.com/ml/cygwin/2015-09/msg00374.html
>> https://cygwin.com/ml/cygwin/2015-09/msg00436.html
>>
I don't think this applies to our case. We use massive parallel processing, and 
the problem is related to that as the test case shows in our environment. In 
single thread operation we don't have any problems at all. I don't use fork or 
other of the tools mentioned. We don't have Chrome or Comodo or so installed. 
We have an encapsulated environment with not even an anti-virus sw running in 
the power workstations and as little stuff as possible because computing speed 
is our main issue.

>> Have you by chance some potential suspect like usual ones
>>   https://cygwin.com/faq/faq.html#faq.using.bloda
I did not find there anything that seems related to our problem.

>> On your cygcheck output I notice nothing strange.
I do not think there is anything strange. I have been using Cygwin for 15+ 
years now. We started parallelizing our jobs some 12 years ago. Of course, 
hardware was not comparable then to what we have today. But the Bad File 
Descriptor issues only started some 3 or 4 years ago with an update of Cygwin 
(I really don't remember when; there must have been some major change in the 
Cygwin-dll: E. g., since then the type-ahead buffer of cmd.exe is no longer 
useable when Cygwin programs run in the shell). Since these errors were fairly 
rare (say, 1 in >1000 tiles), we did not dig into it deeper. However, it is an 
ongoing issue.

With raising workload at the file server and new workstations with more cores 
(allowing for more parallel processes) it became more frequent during last 
years. A server upgrade last winter reduced the problem, but with recently 
massively increasing work load it raise again.

>> Can you provide the type of network disk with
>> /usr/lib/csih/getVolInfo <volumename>
I am sorry, I have a very small installation of Cygwin running with no 
getVolInfo. In which package can I find that? We have MS Windows Server 2008 
that provides network shares.


Again I want to stress: Running the jobs in single thread we never experienced 
any such problems at all. Only with several jobs running in parallel (the same 
batch job is started in several cmd-shell windows independently) we have these 
errors. The reason is obviously when by chance two processes try to access the 
same file at the same time which happens not often, but it happens. I assume 
access to local files is better synchronized by the CPU, whereas at the server 
there may arise these conflicts.

The major question is, what is the underlying access problem within Cygwin? As 
mentioned, the MS programs (e. g. copy) never show a similar problem.
 
Thanks for your help,
Wolfgang


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