[Darshan-users] getting plots
Burlen Loring
bloring at lbl.gov
Tue Mar 15 11:18:01 CDT 2016
I let darshan job summary run all night, still going but no indication
of progress.
This is my first experience with darshan, let me ask a naive question:
is it possible to extract time series for a single process? write
bandwidth over time for instance? and time for file open (or close) vs time?
Thanks for all your help
Burlen
On 03/14/2016 09:53 PM, Burlen Loring wrote:
> Yes, you are correct, it's file per process on 6496 processes, and the
> simulation runs for 100 time steps, plus there are some header files
> and directories created (I think by rank 0). It doesn't seem like too
> extreme of a case to me. We will also run 50k cores for 100 time
> steps. It sounds like darshan can't analyze this type of i/o, but
> please let me know if you have any ideas!
>
> On the size discrepancy. My fault. Darshan had the size correct. I was
> looking at the wrong output file, 200G is the size of the smaller run
> (812 procs). I apologize that I didn't notice that sooner!
>
> On 03/14/2016 08:55 PM, Shane Snyder wrote:
>> Maybe the reason the job summary graphs are hanging might be due to
>> the number of files the application is opening? It looks like there
>> are over 500,000 files (100 each for 6,496 processes). I haven't
>> tried generating graphs for any logs that large myself, but that
>> might be beyond what the graphing utilities can realistically handle.
>> It takes forever for me to even parse the logs in text form.
>>
>> As for the discrepancy in size, that may just be due to what the 'du'
>> utility is actually reporting. 'du' measures the size of a given file
>> based on the underlying file system block size. If the file is 1
>> byte, and the block size is 1 MiB, the file is reported as 1 MiB.
>> Additionally, if you run 'du' on a directory containing numerous
>> subdirectories (as you have, 100 subdirectories), it counts the sizes
>> of the directories as well. Darshan will only report the I/O observed
>> at the application level, so it does not account for file system
>> blocks or directories. You can use 'du -b' to show the "actual"
>> (i.e., not rounded up to block sizes) of individual files, though it
>> still counts subdirectory sizes when determining the size of a given
>> directory. If you do that, is it closer to what Darshan reports?
>>
>> --Shane
>>
>> On 03/14/2016 06:44 PM, Burlen Loring wrote:
>>> sure, here is the link
>>> https://drive.google.com/open?id=0B3y5yyus32lveHljWkExal9TVmM
>>>
>>> On 03/14/2016 03:56 PM, Shane Snyder wrote:
>>>> Hi Burlen,
>>>>
>>>> Would you mind sharing your Darshan log with us? If you prefer, you
>>>> can send it to me off-list, or if it contains sensitive information
>>>> we can give you details on how to anonymize parts of it (e.g., file
>>>> names, etc.).
>>>>
>>>> I don't know for sure what the historical reason the "(may be
>>>> incorrect)" caveat is given with the total bytes read and written.
>>>> Someone correct me if I'm wrong, but I suspect that is to warn
>>>> against the possibility that the code actually wrote/read more data
>>>> than expected from the application's point of view? For instance,
>>>> an I/O optimization called data sieving is possible at the MPI-IO
>>>> layer which results in more data being read than expected from the
>>>> application's point of view to improve performance. That shouldn't
>>>> account for the drastic discrepancy you are seeing, though, so
>>>> perhaps something else is up.
>>>>
>>>> Thanks,
>>>> --Shane
>>>>
>>>> On 03/14/2016 05:29 PM, Burlen Loring wrote:
>>>>> Hi, I'd like to analyze our runs with darshan. I'm able to get the
>>>>> log files, but so far no luck plotting them.
>>>>>
>>>>> In the terminal after a while I see the following output, but then
>>>>> the program appears to hang. After ~20 min of no output and no
>>>>> evidence of it running in top, I killed it, and I didn't see any
>>>>> newly created files.
>>>>>
>>>>> I'm also wondering about the total bytes report and warning that
>>>>> it may be wrong. it does indeed seem way off, du reports 1.6T, but
>>>>> darshan only reports ~200G.
>>>>>
>>>>> Please, let me know what I did wrong! and if I should I be
>>>>> concerned about the numbers being so far off.
>>>>>
>>>>> Thanks
>>>>> Burlen
>>>>>
>>>>> $/work/apps/darshan/3.0.0-pre/bin/darshan-job-summary.pl
>>>>> loring_oscillator_id1336621_3-14-37256-5315836542621785504_1.darshan
>>>>> Slowest unique file time: 25.579892
>>>>> Slowest shared file time: 0
>>>>> Total bytes read and written by app (may be incorrect): 214218545937
>>>>> Total absolute I/O time: 25.579892
>>>>> **NOTE: above shared and unique file times calculated using MPI-IO
>>>>> timers if MPI-IO interface used on a given file, POSIX timers
>>>>> otherwise.
>>>>> _______________________________________________
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>>>>> Darshan-users at lists.mcs.anl.gov
>>>>> https://lists.mcs.anl.gov/mailman/listinfo/darshan-users
>>>>
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>>
>
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