Hi Phil, > > I did find one odd result, although it is somewhat unrelated. In an > earlier email on this topic I mentioned that I was able to find a > temporary workaround for the bug by setting PVFS2_BUFMAP_DESC_COUNT to > 1, which limits pvfs2-client-core to only performing one I/O operation > at a time. A surprising side effect of this was that (regardless of the > flow post order) this configuration substantially increased performance > for a 5 process I/O benchmark. > > In this particular test there are 5 processes, each both reading and > writing large files on the same PVFS2 file system. The results are > counter-intuitive, because the whole point of having multiple buffers > was to allow more concurrent activity when multiple processes perform > I/O. However, the test went faster when only one I/O operation was > allowed to proceed at a time.
Wow.. That is interesting indeed. I will see if I can trigger this behavior as well..Thanks for the info! Murali _______________________________________________ Pvfs2-developers mailing list [email protected] http://www.beowulf-underground.org/mailman/listinfo/pvfs2-developers
