[mpich-discuss] executing time

[bob ilgner]

Hi WL,

Had a quick look at the code and note that you can NOT run this as a serial
process, i.e. using only 1 node. You will need to change code for that. -n 1
does not run anything.

I've added a few printf comments and wall clock timings to show when the
code is running, and not running, i.e. with -n 1 it does not run. Try it out
with these markers and see how it works out.

Regards, bob



On Tue, Jul 14, 2009 at 4:00 PM, samantha lin <wl8150 at googlemail.com> wrote:

> Hi Bob,
>
> Yes, that was the command I executed. Apart from '2' processes, I also
> tried a variety of numbers
> and found '-n 1' is the fastest. I also made another similar C program
> without using the MPI libraries.
> The result was faster than '-n 1'. I didn't put a timing marks in the
> program; instead, I use 'time' command
> prefixing the executing command, e.g. "time mpiexec -n 2 myprog". (should
> be okay?)
> I added my program to this email. Hope that helps.
>
> Regards,
> WL
>
> On Tue, Jul 14, 2009 at 2:25 PM, bob ilgner <bobilgner at gmail.com> wrote:
>
>> Hi WL,
>>
>> What mpiexec command are you using to run your program ? i.e. "mpiexec -n
>> 2 xprogy"
>> where xprogy is the name of your program ?
>>
>> What is your timing for the serial case and the timing for the multiple
>> core case ? Is it a short program that you can list here so we can have a
>> look at it ? Have you tried to place timing marks in the program to analyse
>> what is happening ?
>>
>> Regards, bob
>>
>>
>> On Tue, Jul 14, 2009 at 1:42 PM, samantha lin <wl8150 at googlemail.com>wrote:
>>
>>> Hi bob,
>>>
>>> It's running on a macbook pro(intel cpu 2 cores); just one laptop and
>>> filesystem
>>> is local.
>>>
>>> Regards,
>>> WL
>>> On Tue, Jul 14, 2009 at 5:37 AM, bob ilgner <bobilgner at gmail.com> wrote:
>>>
>>>> Hi WL,
>>>>
>>>> What hardware are you running the mpiexec on and what sort of process is
>>>> this ? A little description please.
>>>>
>>>> Regards, bob
>>>>
>>>> On Tue, Jul 14, 2009 at 12:49 AM, samantha lin <wl8150 at googlemail.com>wrote:
>>>>
>>>>> Hi there,
>>>>> I am new to MPICH. I just finished a test program which does
>>>>> matrix multiplication. When I used 'mpiexec' to execute the
>>>>> program, I found that the more processes, the longer it takes.
>>>>> Not sure if the result is correct or not? Or I should do some
>>>>> things more to improve it?
>>>>>
>>>>> WL
>>>>>
>>>>
>>>>
>>>
>>
>
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