A silly bug in io-bm
By joe
- 1 minutes read - 108 wordsIt wasn’t enough to impact results, but it was enough to cause questioning my results (and sanity).
Part of the IO operation is having N processes write to 1 file. To make this happen correctly, each process has to compute their offset into the file, and start operations from there.
There is a seek involved. Now if I am smart, it won’t be
lseek(file_descriptor,0,SEEK_SET);
Nope … that would be wrong (the zero).
Having the line like this would mean that 128 GB sized files … might not look like 256 GB sized files.
[root@jr5 ~]# ls -alF /data/file
-rwx------ 1 root root 274877906944 Jul 21 20:43 /data/file*
grrrr….