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<div>Hi Cormac,<br>
<br>
That's strange. The -i 2 and -m options are making IOR attempt to read two files: testfile.0 and testfile.1. Darshan is definitely aware of those files, but not only are the read counters missing but also the open counters. It only shows a stat from each
rank for the files in question.<br>
<br>
Can you confirm that both of the files exist and are big enough to accommodate the requested read volume? I wonder if IOR might stat the files up front and exit early if they aren't the correct size?<br>
<br>
Could you also share the output of "ldd ior"? I'm curious to make sure there isn't anything unusual about the libraries linked in, but usually if that were a problem you wouldn't get a log at all.<br>
<br>
Also one last idea, does the behavior change if you remove the -B (O_DIRECT) option? That shouldn't matter from Darshan's perspective, but it might not hurt to check.<br>
<br>
thanks,<br>
-Phil<br>
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<p>On 2018-11-20 19:59:55-05:00 Darshan-users wrote:</p>
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<div dir="ltr">Hello,
<div>I recently installed Darshan 3.1.6 on Microsoft Azure VM running Centos 7.4.</div>
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<div>I got an unexpected result using Darshan to characterize the I/O for an IOR benchmark</div>
<div>experiment. </div>
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<div>export LD_PRELOAD=/avere/apps/spack/linux-centos7-x86_64/gcc-4.8.5/darshan-runtime-3.1.6-daohky4yevagxajjl33lwk472lcgn6g4/lib/libdarshan.so</div>
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<div>BLOCKSIZE=256M</div>
<div>mpirun -np 8 ior -a POSIX -B -r -k -z -v -o $FILEPATH -i 2 -m -t 32m -b 256M -d 1 </div>
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<div>After the job completed, a Darshan log file was created, the resulting text report (darshan-parser_ior_read_shared.out, its attached) was generated using the following command</div>
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<div>darshan-parser --all testuser_ior_id22-20-80229-14589323501426222819_1.darshan >& darshan-parser_ior_read_shared.out</div>
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<div>The above IOR benchmark is a read only benchmark to a shared file system, but the resulting darshan report indicates there are no READ operations?</div>
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<div>Any ideas why the resulting Darshan resport has no read operations? (Note if I add a -w option to the above IOR benchmark (i.e do a write and read to a shared filesystem, darshan only</div>
<div>reports the writes and not reads?)</div>
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<div>Any help would be appreciated,</div>
<div>Thanks for your support,</div>
<div>Cormac.</div>
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