> > P.S. In case of no compression customization of Streamers can significantly improve > > the I/O performance (I saw improvements by a factor of 3), so it seems to be a > > very reasonable option to consider. > > Rene Brun wrote: > I am surprised by your statement about the factor 3. Could you send me > an example of a class where you obtain this result? > > Hi Rene, take a look at http://ncdf41.fnal.gov/murat/Stntuple/html/TCalDataBlock.html. For this class, after turning off compression, I saw a factor of 3 difference between the I/O rate in split (4.2 MBytes/sec on read) and non-split (14 MBytes/sec on read) modes on FCDFSGI2.FNAL.GOV using ROOT 2.26.x (FNAL nomenclature) compiled with KCC-4.0 in debug mode. I attribute the difference to the customized TCalTower::Streamer - see http://ncdf41.fnal.gov/murat/Stntuple/html/src/TCalTower.cxx.html#TCalTower:Streamer -best, Pasha
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