[mpich-discuss] stdin redirection
thakur at mcs.anl.gov
Wed Jun 8 08:02:19 CDT 2016
You could read the input parameters by storing them in a text file and then using fopen and fscanf.
> On Jun 8, 2016, at 7:50 AM, Filippone, Salvatore <Salvatore.Filippone at cranfield.ac.uk> wrote:
> The key term here is "larg(ish)", which I used in my original email to
> mean something larger than the limit I was hitting (64KB) but not
> *really* large (in my original case I was using a file of around 300KB).
> I naturally moved to normal file I/O; MPI I/O was not quite called for,
> because these were just the control parameters for a series of benchmark
> runs, not actual input data (which was read and handled separately).
> On Wed, 2016-06-08 at 12:46 +0000, Balaji, Pavan wrote:
>> If you want to read large files, you should really use MPI-I/O, not
>> stdin. We support reading from stdin for users who migrate from
>> sequential programs to parallel programming, but that's not meant to be
>> the real mechanism to read files. I'm not supportive of trying to
>> modify mpich for such use cases.
>> -- Pavan
>>> On Jun 5, 2016, at 11:18 AM, Seo, Sangmin <sseo at anl.gov> wrote:
>>> Hello Salvatore,
>>> The current MPICH uses pipe to redirect stdin to processes, but pipe
>> has a limited capacity (e.g., 64KB in Linux. Please refer to
>> http://man7.org/linux/man-pages/man7/pipe.7.html). Therefore, if we
>> redirect a file, which is larger than the pipe capacity, to stdin, the
>> current MPICH implementation is not handling it properly because write()
>> does not succeed to write a large data (> the pipe capacity) to the pipe
>> for stdin.
>>> I created a ticket for this issue
>> (https://trac.mpich.org/projects/mpich/ticket/2336), but I'd recommend
>> you to use file I/O in order to handle a large file instead of using
>> stdin redirection.
>>> — Sangmin
> discuss mailing list discuss at mpich.org
> To manage subscription options or unsubscribe:
discuss mailing list discuss at mpich.org
To manage subscription options or unsubscribe:
More information about the discuss